kernel: tracepoints: add support for relative references

To avoid the need for relocating absolute references to tracepoint
structures at boot time when running relocatable kernels (which may
take a disproportionate amount of space), add the option to emit
these tables as relative references instead.

Link: http://lkml.kernel.org/r/20180704083651.24360-7-ard.biesheuvel@linaro.org
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <james.morris@microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PCI: Add support for relative addressing in quirk tables

Allow the PCI quirk tables to be emitted in a way that avoids absolute
references to the hook functions. This reduces the size of the entries,
and, more importantly, makes them invariant under runtime relocation
(e.g., for KASLR)

Link: http://lkml.kernel.org/r/20180704083651.24360-6-ard.biesheuvel@linaro.org
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <james.morris@microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

init: allow initcall tables to be emitted using relative references

Allow the initcall tables to be emitted using relative references that
are only half the size on 64-bit architectures and don't require fixups
at runtime on relocatable kernels.

Link: http://lkml.kernel.org/r/20180704083651.24360-5-ard.biesheuvel@linaro.org
Acked-by: James Morris <james.morris@microsoft.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

module: use relative references for __ksymtab entries

An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab entries,
each consisting of two 64-bit fields containing absolute references, to
the symbol itself and to a char array containing its name, respectively.

When we build the same configuration with KASLR enabled, we end up with an
additional ~192 KB of relocations in the .init section, i.e., one 24 byte
entry for each absolute reference, which all need to be processed at boot
time.

Given how the struct kernel_symbol that describes each entry is completely
local to module.c (except for the references emitted by EXPORT_SYMBOL()
itself), we can easily modify it to contain two 32-bit relative references
instead.  This reduces the size of the __ksymtab section by 50% for all
64-bit architectures, and gets rid of the runtime relocations entirely for
architectures implementing KASLR, either via standard PIE linking (arm64)
or using custom host tools (x86).

Note that the binary search involving __ksymtab contents relies on each
section being sorted by symbol name.  This is implemented based on the
input section names, not the names in the ksymtab entries, so this patch
does not interfere with that.

Given that the use of place-relative relocations requires support both in
the toolchain and in the module loader, we cannot enable this feature for
all architectures.  So make it dependent on whether
CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined.

Link: http://lkml.kernel.org/r/20180704083651.24360-4-ard.biesheuvel@linaro.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <james.morris@microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

module: allow symbol exports to be disabled

To allow existing C code to be incorporated into the decompressor or the
UEFI stub, introduce a CPP macro that turns all EXPORT_SYMBOL_xxx
declarations into nops, and #define it in places where such exports are
undesirable.  Note that this gets rid of a rather dodgy redefine of
linux/export.h's header guard.

Link: http://lkml.kernel.org/r/20180704083651.24360-3-ard.biesheuvel@linaro.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <james.morris@microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch: enable relative relocations for arm64, power and x86

Patch series "add support for relative references in special sections", v10.

This adds support for emitting special sections such as initcall arrays,
PCI fixups and tracepoints as relative references rather than absolute
references.  This reduces the size by 50% on 64-bit architectures, but
more importantly, it removes the need for carrying relocation metadata for
these sections in relocatable kernels (e.g., for KASLR) that needs to be
fixed up at boot time.  On arm64, this reduces the vmlinux footprint of
such a reference by 8x (8 byte absolute reference + 24 byte RELA entry vs
4 byte relative reference)

Patch #3 was sent out before as a single patch.  This series supersedes
the previous submission.  This version makes relative ksymtab entries
dependent on the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS rather
than trying to infer from kbuild test robot replies for which
architectures it should be blacklisted.

Patch #1 introduces the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS,
and sets it for the main architectures that are expected to benefit the
most from this feature, i.e., 64-bit architectures or ones that use
runtime relocations.

Patch #2 add support for #define'ing __DISABLE_EXPORTS to get rid of
ksymtab/kcrctab sections in decompressor and EFI stub objects when
rebuilding existing C files to run in a different context.

Patches #4 - #6 implement relative references for initcalls, PCI fixups
and tracepoints, respectively, all of which produce sections with order
~1000 entries on an arm64 defconfig kernel with tracing enabled.  This
means we save about 28 KB of vmlinux space for each of these patches.

[From the v7 series blurb, which included the jump_label patches as well]:

  For the arm64 kernel, all patches combined reduce the memory footprint
  of vmlinux by about 1.3 MB (using a config copied from Ubuntu that has
  KASLR enabled), of which ~1 MB is the size reduction of the RELA section
  in .init, and the remaining 300 KB is reduction of .text/.data.

This patch (of 6):

Before updating certain subsystems to use place relative 32-bit
relocations in special sections, to save space and reduce the number of
absolute relocations that need to be processed at runtime by relocatable
kernels, introduce the Kconfig symbol and define it for some architectures
that should be able to support and benefit from it.

Link: http://lkml.kernel.org/r/20180704083651.24360-2-ard.biesheuvel@linaro.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: James Morris <jmorris@namei.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Cc: James Morris <james.morris@microsoft.com>
Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

spelling.txt: add more spellings to spelling.txt

Here are some of the more common spelling mistakes and typos that I've
found while fixing up spelling mistakes in the kernel over the past 6
months.

Link: http://lkml.kernel.org/r/20180629150603.1159-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/hung_task.c: allow to set checking interval separately from timeout

Currently task hung checking interval is equal to timeout, as the result
hung is detected anywhere between timeout and 2*timeout.  This is fine for
most interactive environments, but this hurts automated testing setups
(syzbot).  In an automated setup we need to strictly order CPU lockup <
RCU stall < workqueue lockup < task hung < silent loss, so that RCU stall
is not detected as task hung and task hung is not detected as silent
machine loss.  The large variance in task hung detection timeout requires
setting silent machine loss timeout to a very large value (e.g.  if task
hung is 3 mins, then silent loss need to be set to ~7 mins).  The
additional 3 minutes significantly reduce testing efficiency because
usually we crash kernel within a minute, and this can add hours to bug
localization process as it needs to do dozens of tests.

Allow setting checking interval separately from timeout.  This allows to
set timeout to, say, 3 minutes, but checking interval to 10 secs.

The interval is controlled via a new hung_task_check_interval_secs sysctl,
similar to the existing hung_task_timeout_secs sysctl.  The default value
of 0 results in the current behavior: checking interval is equal to
timeout.

[akpm@linux-foundation.org: update hung_task_timeout_max's comment]
Link: http://lkml.kernel.org/r/20180611111004.203513-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/crash_core.c: print timestamp using time64_t

The get_seconds() call returns a 32-bit timestamp on some architectures,
and will overflow in the future.  The newer ktime_get_real_seconds()
always returns a 64-bit timestamp that does not suffer from this problem.

Link: http://lkml.kernel.org/r/20180618150329.941903-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Petr Tesarik <ptesarik@suse.cz>
Cc: Marc-Andr Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

linux/compiler.h: don't use bool

Appararently, it's possible to have a non-trivial TU include a few
headers, including linux/build_bug.h, without ending up with
linux/types.h.  So the 0day bot sent me

config: um-x86_64_defconfig (attached as .config)

>> include/linux/compiler.h:316:3: error: unknown type name 'bool'; did you mean '_Bool'?
      bool __cond = !(condition);    \

for something I'm working on.

Rather than contributing to the #include madness and including
linux/types.h from compiler.h, just use int.

Link: http://lkml.kernel.org/r/20180817101036.20969-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Christopher Li <sparse@chrisli.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

userns: use irqsave variant of refcount_dec_and_lock()

The irqsave variant of refcount_dec_and_lock handles irqsave/restore when
taking/releasing the spin lock.  With this variant the call of
local_irq_save/restore is no longer required.

[bigeasy@linutronix.de: s@atomic_dec_and_lock@refcount_dec_and_lock@g]
Link: http://lkml.kernel.org/r/20180703200141.28415-7-bigeasy@linutronix.de
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

userns: use refcount_t for reference counting instead atomic_t

refcount_t type and corresponding API should be used instead of atomic_t
wh en the variable is used as a reference counter.  This avoids accidental
refcounter overflows that might lead to use-after-free situations.

Link: http://lkml.kernel.org/r/20180703200141.28415-6-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bdi: use irqsave variant of refcount_dec_and_lock()

The irqsave variant of refcount_dec_and_lock handles irqsave/restore when
taking/releasing the spin lock.  With this variant the call of
local_irq_save/restore is no longer required.

[bigeasy@linutronix.de: s@atomic_dec_and_lock@refcount_dec_and_lock@g]
Link: http://lkml.kernel.org/r/20180703200141.28415-5-bigeasy@linutronix.de
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bdi: use refcount_t for reference counting instead atomic_t

refcount_t type and corresponding API should be used instead of atomic_t
when the variable is used as a reference counter.  This permits avoiding
accidental refcounter overflows that might lead to use-after-free
situations.

Link: http://lkml.kernel.org/r/20180703200141.28415-4-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel.h: documentation for roundup() vs round_up()

Things like 3619dec5103d ("dh key: fix rounding up KDF output length")
expose the lack of explicit documentation for roundup() vs round_up().  At
least we can try to document it better if anyone goes looking.

Link: http://lkml.kernel.org/r/20180703041950.GA43464@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/bug.h: clarify valid uses of WARN()

Explicitly state that WARN*() should be used only for recoverable kernel
issues/bugs and that it should not be used for any kind of invalid
external inputs or transient conditions.

Motivation: it's a very useful capability to be able to understand if a
particular kernel splat means a kernel bug or simply an invalid user-space
program.  For the former one wants to notify kernel developers, while
notifying kernel developers for the latter is annoying.  Even a kernel
developer may not know what to do with a WARNING in an unfamiliar
subsystem.  This is especially critical for any automated testing systems
that may use panic_on_warn and mail kernel developers.

The clear separation also serves as an additional documentation: is it a
condition that must never occur because of additional checks/logic
elsewhere?  or is it simply a check for invalid inputs or unfortunate
conditions?

Use of pr_err() for user messages also leads to better error messages.
"Something is wrong in file foo on line X" is not particularly useful
message for end user.  pr_err() forces developers to write more meaningful
error messages for user.

As of now we are almost there.  We are doing systematic kernel testing
with panic_on_warn and are not seeing massive amounts of false positives.
But every now and then another WARN on ENOMEM or invalid inputs pops up
and leads to a lengthy argument each time.  The goal of this change is to
officially document the rules.

Link: http://lkml.kernel.org/r/20180620103716.61636-1-dvyukov@gmail.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/kcore: add vmcoreinfo note to /proc/kcore

The vmcoreinfo information is useful for runtime debugging tools, not just
for crash dumps.  A lot of this information can be determined by other
means, but this is much more convenient, and it only adds a page at most
to the file.

Link: http://lkml.kernel.org/r/fddbcd08eed76344863303878b12de1c1e2a04b6.1531953780.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

crash_core: use VMCOREINFO_SYMBOL_ARRAY() for swapper_pg_dir

This is preparation for allowing CRASH_CORE to be enabled for any
architecture.

swapper_pg_dir is always either an array or a macro expanding to NULL.
In the latter case, VMCOREINFO_SYMBOL() won't work, as it tries to take
the address of the given symbol:

#define VMCOREINFO_SYMBOL(name) \
vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)&name)

Instead, use VMCOREINFO_SYMBOL_ARRAY(), which uses the value:

#define VMCOREINFO_SYMBOL_ARRAY(name) \
vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)name)

This is the same thing for the array case but isn't an error for the macro
case.

Link: http://lkml.kernel.org/r/c05f9781ec204f40fc96f95086e7b6de6a3eb2c3.1532563124.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/kcore: optimize multiple page reads

The current code does a full search of the segment list every time for
every page.  This is wasteful, since it's almost certain that the next
page will be in the same segment.  Instead, check if the previous segment
covers the current page before doing the list search.

Link: http://lkml.kernel.org/r/fd346c11090cf93d867e01b8d73a6567c5ac6361.1531953780.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/kcore: clean up ELF header generation

Currently, the ELF file header, program headers, and note segment are
allocated all at once, in some icky code dating back to 2.3.  Programs
tend to read the file header, then the program headers, then the note
segment, all separately, so this is a waste of effort.  It's cleaner and
more efficient to handle the three separately.

Link: http://lkml.kernel.org/r/19c92cbad0e11f6103ff3274b2e7a7e51a1eb74b.1531953780.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/kcore: hold lock during read

Now that we're using an rwsem, we can hold it during the entirety of
read_kcore() and have a common return path.  This is preparation for the
next change.

[akpm@linux-foundation.org: fix locking bug reported by Tetsuo Handa]
Link: http://lkml.kernel.org/r/d7cfbc1e8a76616f3b699eaff9df0a2730380534.1531953780.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/kcore: fix memory hotplug vs multiple opens race

There's a theoretical race condition that will cause /proc/kcore to miss
a memory hotplug event:

CPU0                              CPU1
// hotplug event 1
kcore_need_update = 1

open_kcore()                      open_kcore()
    kcore_update_ram()                kcore_update_ram()
        // Walk RAM                       // Walk RAM
        __kcore_update_ram()              __kcore_update_ram()
            kcore_need_update = 0

// hotplug event 2
kcore_need_update = 1
                                              kcore_need_update = 0

Note that CPU1 set up the RAM kcore entries with the state after hotplug
event 1 but cleared the flag for hotplug event 2.  The RAM entries will
therefore be stale until there is another hotplug event.

This is an extremely unlikely sequence of events, but the fix makes the
synchronization saner, anyways: we serialize the entire update sequence,
which means that whoever clears the flag will always succeed in replacing
the kcore list.

Link: http://lkml.kernel.org/r/6106c509998779730c12400c1b996425df7d7089.1531953780.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/kcore: replace kclist_lock rwlock with rwsem

Now we only need kclist_lock from user context and at fs init time, and
the following changes need to sleep while holding the kclist_lock.

Link: http://lkml.kernel.org/r/521ba449ebe921d905177410fee9222d07882f0d.1531953780.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/kcore: don't grab lock for memory hotplug notifier

The memory hotplug notifier kcore_callback() only needs kclist_lock to
prevent races with __kcore_update_ram(), but we can easily eliminate that
race by using an atomic xchg() in __kcore_update_ram().  This is
preparation for converting kclist_lock to an rwsem.

Link: http://lkml.kernel.org/r/0a4bc89f4dbde8b5b2ea309f7b4fb6a85fe29df2.1531953780.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc/kcore: don't grab lock for kclist_add()

Patch series "/proc/kcore improvements", v4.

This series makes a few improvements to /proc/kcore.  It fixes a couple of
small issues in v3 but is otherwise the same.  Patches 1, 2, and 3 are
prep patches.  Patch 4 is a fix/cleanup.  Patch 5 is another prep patch.
Patches 6 and 7 are optimizations to ->read().  Patch 8 makes it possible
to enable CRASH_CORE on any architecture, which is needed for patch 9.
Patch 9 adds vmcoreinfo to /proc/kcore.

This patch (of 9):

kclist_add() is only called at init time, so there's no point in grabbing
any locks.  We're also going to replace the rwlock with a rwsem, which we
don't want to try grabbing during early boot.

While we're here, mark kclist_add() with __init so that we'll get a
warning if it's called from non-init code.

Link: http://lkml.kernel.org/r/98208db1faf167aa8b08eebfa968d95c70527739.1531953780.git.osandov@fb.com
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Tested-by: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/kcore.c: use __pa_symbol() for KCORE_TEXT list entries

elf_kcore_store_hdr() uses __pa() to find the physical address of
KCORE_RAM or KCORE_TEXT entries exported as program headers.

This trips CONFIG_DEBUG_VIRTUAL's checks, as the KCORE_TEXT entries are
not in the linear map.

Handle these two cases separately, using __pa_symbol() for the KCORE_TEXT
entries.

Link: http://lkml.kernel.org/r/20180711131944.15252-1-james.morse@arm.com
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Omar Sandoval <osandov@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/vmcore.c: use new typedef vm_fault_t

Use new return type vm_fault_t for fault handler in struct
vm_operations_struct.  For now, this is just documenting that the function
returns a VM_FAULT value rather than an errno.  Once all instances are
converted, vm_fault_t will become a distinct type.

See 1c8f422059ae ("mm: change return type to vm_fault_t") for reference.

Link: http://lkml.kernel.org/r/20180702153325.GA3875@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ganesh Goudar <ganeshgr@chelsio.com>
Cc: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: use "unsigned int" in /proc/stat hook

Number of CPUs is never high enough to force 64-bit arithmetic.
Save couple of bytes on x86_64.

Link: http://lkml.kernel.org/r/20180627200710.GC18434@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: spread "const" a bit

Link: http://lkml.kernel.org/r/20180627200614.GB18434@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: use macro in /proc/latency hook

->latency_record is defined as

struct latency_record[LT_SAVECOUNT];

so use the same macro whie iterating.

Link: http://lkml.kernel.org/r/20180627200534.GA18434@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: save 2 atomic ops on write to "/proc/*/attr/*"

Code checks if write is done by current to its own attributes.
For that get/put pair is unnecessary as it can be done under RCU.

Note: rcu_read_unlock() can be done even earlier since pointer to a task
is not dereferenced. It depends if /proc code should look scary or not:

rcu_read_lock();
task = pid_task(...);
rcu_read_unlock();
if (!task)
return -ESRCH;
if (task != current)
return -EACCESS:

P.S.: rename "length" variable. Code like this

length = -EINVAL;

should not exist.

Link: http://lkml.kernel.org/r/20180627200218.GF18113@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: put task earlier in /proc/*/fail-nth

Link: http://lkml.kernel.org/r/20180627195427.GE18113@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: smaller readlock section in readdir("/proc")

Readdir context is thread local, so ->pos is thread local,
move it out of readlock.

Link: http://lkml.kernel.org/r/20180627195339.GD18113@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: test /proc/thread-self symlink

Same story: I have WIP patch to make it faster, so better have a test
as well.

Link: http://lkml.kernel.org/r/20180627195209.GC18113@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: test /proc/self symlink

There are plans to change how /proc/self result is calculated,
for that a test is necessary.

Use direct system call because of this whole getpid caching story.

Link: http://lkml.kernel.org/r/20180627195103.GB18113@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/uptime.c: use ktime_get_boottime_ts64

get_monotonic_boottime() is deprecated and uses the old timespec type.
Let's convert /proc/uptime to use ktime_get_boottime_ts64().

Link: http://lkml.kernel.org/r/20180620081746.282742-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc: fixup PDE allocation bloat

24074a35c5c975 ("proc: Make inline name size calculation automatic")
started to put PDE allocations into kmalloc-256 which is unnecessary as
~40 character names are very rare.

Put allocation back into kmalloc-192 cache for 64-bit non-debug builds.

Put BUILD_BUG_ON to know when PDE size has gotten out of control.

[adobriyan@gmail.com: fix BUILD_BUG_ON breakage on powerpc64]
Link: http://lkml.kernel.org/r/20180703191602.GA25521@avx2
Link: http://lkml.kernel.org/r/20180617215732.GA24688@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: fix comment for NODEMASK_ALLOC

Currently, NODEMASK_ALLOC allocates a nodemask_t with kmalloc when
NODES_SHIFT is higher than 8, otherwise it declares it within the stack.

The comment says that the reasoning behind this, is that nodemask_t will
be 256 bytes when NODES_SHIFT is higher than 8, but this is not true.  For
example, NODES_SHIFT = 9 will give us a 64 bytes nodemask_t.  Let us fix
up the comment for that.

Another thing is that it might make sense to let values lower than
128bytes be allocated in the stack.  Although this all depends on the
depth of the stack (and this changes from function to function), I think
that 64 bytes is something we can easily afford.  So we could even bump
the limit by 1 (from > 8 to > 9).

Link: http://lkml.kernel.org/r/20180820085516.9687-1-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/block/zram/zram_drv.c: fix bug storing backing_dev

The call to strlcpy in backing_dev_store is incorrect. It should take
the size of the destination buffer instead of the size of the source
buffer.  Additionally, ignore the newline character (\n) when reading
the new file_name buffer. This makes it possible to set the backing_dev
as follows:

echo /dev/sdX > /sys/block/zram0/backing_dev

The reason it worked before was the fact that strlcpy() copies 'len - 1'
bytes, which is strlen(buf) - 1 in our case, so it accidentally didn't
copy the trailing new line symbol.  Which also means that "echo -n
/dev/sdX" most likely was broken.

Signed-off-by: Peter Kalauskas <peskal@google.com>
Link: http://lkml.kernel.org/r/20180813061623.GC64836@rodete-desktop-imager.corp.google.com
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: <stable@vger.kernel.org> [4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

/proc/meminfo: add percpu populated pages count

Currently, percpu memory only exposes allocation and utilization
information via debugfs.  This more or less is only really useful for
understanding the fragmentation and allocation information at a per-chunk
level with a few global counters.  This is also gated behind a config.
BPF and cgroup, for example, have seen an increase in use causing
increased use of percpu memory.  Let's make it easier for someone to
identify how much memory is being used.

This patch adds the "Percpu" stat to meminfo to more easily look up how
much percpu memory is in use.  This number includes the cost for all
allocated backing pages and not just insight at the per a unit, per chunk
level.  Metadata is excluded.  I think excluding metadata is fair because
the backing memory scales with the numbere of cpus and can quickly
outweigh the metadata.  It also makes this calculation light.

Link: http://lkml.kernel.org/r/20180807184723.74919-1-dennisszhou@gmail.com
Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, oom: introduce memory.oom.group

For some workloads an intervention from the OOM killer can be painful.
Killing a random task can bring the workload into an inconsistent state.

Historically, there are two common solutions for this
problem:
1) enabling panic_on_oom,
2) using a userspace daemon to monitor OOMs and kill
   all outstanding processes.

Both approaches have their downsides: rebooting on each OOM is an obvious
waste of capacity, and handling all in userspace is tricky and requires a
userspace agent, which will monitor all cgroups for OOMs.

In most cases an in-kernel after-OOM cleaning-up mechanism can eliminate
the necessity of enabling panic_on_oom.  Also, it can simplify the cgroup
management for userspace applications.

This commit introduces a new knob for cgroup v2 memory controller:
memory.oom.group.  The knob determines whether the cgroup should be
treated as an indivisible workload by the OOM killer.  If set, all tasks
belonging to the cgroup or to its descendants (if the memory cgroup is not
a leaf cgroup) are killed together or not at all.

To determine which cgroup has to be killed, we do traverse the cgroup
hierarchy from the victim task's cgroup up to the OOMing cgroup (or root)
and looking for the highest-level cgroup with memory.oom.group set.

Tasks with the OOM protection (oom_score_adj set to -1000) are treated as
an exception and are never killed.

This patch doesn't change the OOM victim selection algorithm.

Link: http://lkml.kernel.org/r/20180802003201.817-4-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, oom: refactor oom_kill_process()

Patch series "introduce memory.oom.group", v2.

This is a tiny implementation of cgroup-aware OOM killer, which adds an
ability to kill a cgroup as a single unit and so guarantee the integrity
of the workload.

Although it has only a limited functionality in comparison to what now
resides in the mm tree (it doesn't change the victim task selection
algorithm, doesn't look at memory stas on cgroup level, etc), it's also
much simpler and more straightforward.  So, hopefully, we can avoid having
long debates here, as we had with the full implementation.

As it doesn't prevent any futher development, and implements an useful and
complete feature, it looks as a sane way forward.

This patch (of 2):

oom_kill_process() consists of two logical parts: the first one is
responsible for considering task's children as a potential victim and
printing the debug information.  The second half is responsible for
sending SIGKILL to all tasks sharing the mm struct with the given victim.

This commit splits oom_kill_process() with an intention to re-use the the
second half: __oom_kill_process().

The cgroup-aware OOM killer will kill multiple tasks belonging to the
victim cgroup.  We don't need to print the debug information for the each
task, as well as play with task selection (considering task's children),
so we can't use the existing oom_kill_process().

Link: http://lkml.kernel.org/r/20171130152824.1591-2-guro@fb.com
Link: http://lkml.kernel.org/r/20180802003201.817-3-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/vm/: add MAP_POPULATE test

As with many other projects, we use some shmalloc allocator.  At some
point we need to make a part of allocated pages back private to process.
And it should be populated straight away.  Check that (MAP_PRIVATE |
MAP_POPULATE) actually copies the private page.

[akpm@linux-foundation.org: change message, per review discussion]
Link: http://lkml.kernel.org/r/20180801233636.29354-1-dima@arista.com
Signed-off-by: Dmitry Safonov <dima@arista.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Hua Zhong <hzhong@arista.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stuart Ritchie <sritchie@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc: Introduce free_area_init_core_hotplug

Currently, whenever a new node is created/re-used from the memhotplug
path, we call free_area_init_node()->free_area_init_core().  But there is
some code that we do not really need to run when we are coming from such
path.

free_area_init_core() performs the following actions:

1) Initializes pgdat internals, such as spinlock, waitqueues and more.
2) Account # nr_all_pages and # nr_kernel_pages. These values are used later on
   when creating hash tables.
3) Account number of managed_pages per zone, substracting dma_reserved and
   memmap pages.
4) Initializes some fields of the zone structure data
5) Calls init_currently_empty_zone to initialize all the freelists
6) Calls memmap_init to initialize all pages belonging to certain zone

When called from memhotplug path, free_area_init_core() only performs
actions #1 and #4.

Action #2 is pointless as the zones do not have any pages since either the
node was freed, or we are re-using it, eitherway all zones belonging to
this node should have 0 pages.  For the same reason, action #3 results
always in manages_pages being 0.

Action #5 and #6 are performed later on when onlining the pages:
 online_pages()->move_pfn_range_to_zone()->init_currently_empty_zone()
 online_pages()->move_pfn_range_to_zone()->memmap_init_zone()

This patch does two things:

First, moves the node/zone initializtion to their own function, so it
allows us to create a small version of free_area_init_core, where we only
perform:

1) Initialization of pgdat internals, such as spinlock, waitqueues and more
4) Initialization of some fields of the zone structure data

These two functions are: pgdat_init_internals() and zone_init_internals().

The second thing this patch does, is to introduce
free_area_init_core_hotplug(), the memhotplug version of
free_area_init_core():

Currently, we call free_area_init_node() from the memhotplug path.  In
there, we set some pgdat's fields, and call calculate_node_totalpages().
calculate_node_totalpages() calculates the # of pages the node has.

Since the node is either new, or we are re-using it, the zones belonging
to this node should not have any pages, so there is no point to calculate
this now.

Actually, we re-set these values to 0 later on with the calls to:

reset_node_managed_pages()
reset_node_present_pages()

The # of pages per node and the # of pages per zone will be calculated when
onlining the pages:

online_pages()->move_pfn_range()->move_pfn_range_to_zone()->resize_zone_range()
online_pages()->move_pfn_range()->move_pfn_range_to_zone()->resize_pgdat_range()

Also, since free_area_init_core/free_area_init_node will now only get called during early init, let us replace
__paginginit with __init, so their code gets freed up.

[osalvador@techadventures.net: fix section usage]
Link: http://lkml.kernel.org/r/20180731101752.GA473@techadventures.net
[osalvador@suse.de: v6]
Link: http://lkml.kernel.org/r/20180801122348.21588-6-osalvador@techadventures.net
Link: http://lkml.kernel.org/r/20180730101757.28058-5-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc: inline function to handle CONFIG_DEFERRED_STRUCT_PAGE_INIT

Let us move the code between CONFIG_DEFERRED_STRUCT_PAGE_INIT to an inline
function.  Not having an ifdef in the function makes the code more
readable.

Link: http://lkml.kernel.org/r/20180730101757.28058-4-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: remove __paginginit

__paginginit is the same thing as __meminit except for platforms without
sparsemem, there it is defined as __init.

Remove __paginginit and use __meminit.  Use __ref in one single function
that merges __meminit and __init sections: setup_usemap().

Link: http://lkml.kernel.org/r/20180801122348.21588-4-osalvador@techadventures.net
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: access zone->node via zone_to_nid() and zone_set_nid()

zone->node is configured only when CONFIG_NUMA=y, so it is a good idea to
have inline functions to access this field in order to avoid ifdef's in c
files.

Link: http://lkml.kernel.org/r/20180730101757.28058-3-osalvador@techadventures.net
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c: move ifdefery out of free_area_init_core

Patch series "Refactor free_area_init_core and add
free_area_init_core_hotplug", v6.

This patchset does three things:

 1) Clean up/refactor free_area_init_core/free_area_init_node
    by moving the ifdefery out of the functions.
 2) Move the pgdat/zone initialization in free_area_init_core to its
    own function.
 3) Introduce free_area_init_core_hotplug, a small subset of
    free_area_init_core, which is only called from memhotlug code path. In this
    way, we have:

    free_area_init_core: called during early initialization
    free_area_init_core_hotplug: called whenever a new node is allocated/re-used (memhotplug path)

This patch (of 5):

Moving the #ifdefs out of the function makes it easier to follow.

Link: http://lkml.kernel.org/r/20180730101757.28058-2-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: remove zone_id() and make use of zone_idx() in is_dev_zone()

is_dev_zone() is using zone_id() to check if the zone is ZONE_DEVICE.
zone_id() looks pretty much the same as zone_idx(), and while the use of
zone_idx() is quite spread in the kernel, zone_id() is only being used by
is_dev_zone().

This patch removes zone_id() and makes is_dev_zone() use zone_idx() to
check the zone, so we do not have two things with the same functionality
around.

Link: http://lkml.kernel.org/r/20180730133718.28683-1-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/sysctl/vm.txt: update __vm_enough_memory()'s path

__vm_enough_memory has moved to mm/util.c.

Link: http://lkml.kernel.org/r/E18EDF4A4FA4A04BBFA824B6D7699E532A7E5913@EXMBX-SZMAIL013.tencent.com
Signed-off-by: Juvi Liu <juviliu@tencent.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcg: reduce memcg tree traversals for stats collection

Currently cgroup-v1's memcg_stat_show traverses the memcg tree ~17 times
to collect the stats while cgroup-v2's memory_stat_show traverses the
memcg tree thrice.  On a large machine, a couple thousand memcgs is very
normal and if the churn is high and memcgs stick around during to several
reasons, tens of thousands of nodes in memcg tree can exist.  This patch
has refactored and shared the stat collection code between cgroup-v1 and
cgroup-v2 and has reduced the tree traversal to just one.

I ran a simple benchmark which reads the root_mem_cgroup's stat file
1000 times in the presense of 2500 memcgs on cgroup-v1. The results are:

Without the patch:
$ time ./read-root-stat-1000-times

real    0m1.663s
user    0m0.000s
sys     0m1.660s

With the patch:
$ time ./read-root-stat-1000-times

real    0m0.468s
user    0m0.000s
sys     0m0.467s

Link: http://lkml.kernel.org/r/20180724224635.143944-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Bruce Merry <bmerry@ska.ac.za>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: fix page_freeze_refs and page_unfreeze_refs in comments

page_freeze_refs/page_unfreeze_refs have already been relplaced by
page_ref_freeze/page_ref_unfreeze , but they are not modified in the
comments.

Link: http://lkml.kernel.org/r/1532590226-106038-1-git-send-email-jiang.biao2@zte.com.cn
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: clarify CONFIG_PAGE_POISONING and usage

The Kconfig text for CONFIG_PAGE_POISONING doesn't mention that it has to
be enabled explicitly.  This updates the documentation for that and adds a
note about CONFIG_PAGE_POISONING to the "page_poison" command line docs.
While here, change description of CONFIG_PAGE_POISONING_ZERO too, as it's
not "random" data, but rather the fixed debugging value that would be used
when not zeroing.  Additionally removes a stray "bool" in the Kconfig.

Link: http://lkml.kernel.org/r/20180725223832.GA43733@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: zero out the vma in vma_init()

Rather than in vm_area_alloc().  To ensure that the various oddball
stack-based vmas are in a good state.  Some of the callers were zeroing
them out, others were not.

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mempool.c: add missing parameter description

The kernel-doc for mempool_init function is missing the description of the
pool parameter.  Add it.

Link: http://lkml.kernel.org/r/1532336274-26228-1-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: /proc/pid/smaps_rollup: convert to single value seq_file

The /proc/pid/smaps_rollup file is currently implemented via the
m_start/m_next/m_stop seq_file iterators shared with the other maps files,
that iterate over vma's.  However, the rollup file doesn't print anything
for each vma, only accumulate the stats.

There are some issues with the current code as reported in [1] - the
accumulated stats can get skewed if seq_file start()/stop() op is called
multiple times, if show() is called multiple times, and after seeks to
non-zero position.

Patch [1] fixed those within existing design, but I believe it is
fundamentally wrong to expose the vma iterators to the seq_file mechanism
when smaps_rollup shows logically a single set of values for the whole
address space.

This patch thus refactors the code to provide a single "value" at offset
0, with vma iteration to gather the stats done internally.  This fixes the
situations where results are skewed, and simplifies the code, especially
in show_smap(), at the expense of somewhat less code reuse.

[1] https://marc.info/?l=linux-mm&m=151927723128134&w=2

[vbabka@suse.c: use seq_file infrastructure]
Link: http://lkml.kernel.org/r/bf4525b0-fd5b-4c4c-2cb3-adee3dd95a48@suse.cz
Link: http://lkml.kernel.org/r/20180723111933.15443-5-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Daniel Colascione <dancol@google.com>
Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: /proc/pid/smaps: factor out common stats printing

To prepare for handling /proc/pid/smaps_rollup differently from
/proc/pid/smaps factor out from show_smap() printing the parts of output
that are common for both variants, which is the bulk of the gathered
memory stats.

[vbabka@suse.cz: add const, per Alexey]
Link: http://lkml.kernel.org/r/b45f319f-cd04-337b-37f8-77f99786aa8a@suse.cz
Link: http://lkml.kernel.org/r/20180723111933.15443-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Daniel Colascione <dancol@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: /proc/pid/smaps: factor out mem stats gathering

To prepare for handling /proc/pid/smaps_rollup differently from
/proc/pid/smaps factor out vma mem stats gathering from show_smap() - it
will be used by both.

Link: http://lkml.kernel.org/r/20180723111933.15443-3-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Daniel Colascione <dancol@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: /proc/pid/*maps remove is_pid and related wrappers

Patch series "cleanups and refactor of /proc/pid/smaps*".

The recent regression in /proc/pid/smaps made me look more into the code.
Especially the issues with smaps_rollup reported in [1] as explained in
Patch 4, which fixes them by refactoring the code.  Patches 2 and 3 are
preparations for that.  Patch 1 is me realizing that there's a lot of
boilerplate left from times where we tried (unsuccessfuly) to mark thread
stacks in the output.

Originally I had also plans to rework the translation from
/proc/pid/*maps* file offsets to the internal structures.  Now the offset
means "vma number", which is not really stable (vma's can come and go
between read() calls) and there's an extra caching of last vma's address.
My idea was that offsets would be interpreted directly as addresses, which
would also allow meaningful seeks (see the ugly seek_to_smaps_entry() in
tools/testing/selftests/vm/mlock2.h).  However loff_t is (signed) long
long so that might be insufficient somewhere for the unsigned long
addresses.

So the result is fixed issues with skewed /proc/pid/smaps_rollup results,
simpler smaps code, and a lot of unused code removed.

[1] https://marc.info/?l=linux-mm&m=151927723128134&w=2

This patch (of 4):

Commit b76437579d13 ("procfs: mark thread stack correctly in
proc/<pid>/maps") introduced differences between /proc/PID/maps and
/proc/PID/task/TID/maps to mark thread stacks properly, and this was
also done for smaps and numa_maps.  However it didn't work properly and
was ultimately removed by commit b18cb64ead40 ("fs/proc: Stop trying to
report thread stacks").

Now the is_pid parameter for the related show_*() functions is unused
and we can remove it together with wrapper functions and ops structures
that differ for PID and TID cases only in this parameter.

Link: http://lkml.kernel.org/r/20180723111933.15443-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Daniel Colascione <dancol@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/oom_kill.c: clean up oom_reap_task_mm()

Andrew has noticed some inconsistencies in oom_reap_task_mm.  Notably

 - Undocumented return value.

 - comment "failed to reap part..." is misleading - sounds like it's
   referring to something which happened in the past, is in fact
   referring to something which might happen in the future.

 - fails to call trace_finish_task_reaping() in one case

 - code duplication.

 - Increases mmap_sem hold time a little by moving
   trace_finish_task_reaping() inside the locked region.  So sue me ;)

 - Sharing the finish: path means that the trace event won't
   distinguish between the two sources of finishing.

Add a short explanation for the return value and fix the rest by
reorganizing the function a bit to have unified function exit paths.

Link: http://lkml.kernel.org/r/20180724141747.GP28386@dhcp22.suse.cz
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, oom: describe task memory unit, larger PID pad

The default page memory unit of OOM task dump events might not be
intuitive and potentially misleading for the non-initiated when debugging
OOM events: These are pages and not kBs.  Add a small printk prior to the
task dump informing that the memory units are actually memory _pages_.

Also extends PID field to align on up to 7 characters.
Reference https://lkml.org/lkml/2018/7/3/1201

Link: http://lkml.kernel.org/r/c795eb5129149ed8a6345c273aba167ff1bbd388.1530715938.git.rfreire@redhat.com
Signed-off-by: Rodrigo Freire <rfreire@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, oom: remove oom_lock from oom_reaper

oom_reaper used to rely on the oom_lock since e2fe14564d33 ("oom_reaper:
close race with exiting task").  We do not really need the lock anymore
though.  212925802454 ("mm: oom: let oom_reap_task and exit_mmap run
concurrently") has removed serialization with the exit path based on the
mm reference count and so we do not really rely on the oom_lock anymore.

Tetsuo was arguing that at least MMF_OOM_SKIP should be set under the lock
to prevent from races when the page allocator didn't manage to get the
freed (reaped) memory in __alloc_pages_may_oom but it sees the flag later
on and move on to another victim.  Although this is possible in principle
let's wait for it to actually happen in real life before we make the
locking more complex again.

Therefore remove the oom_lock for oom_reaper paths (both exit_mmap and
oom_reap_task_mm).  The reaper serializes with exit_mmap by mmap_sem +
MMF_OOM_SKIP flag.  There is no synchronization with out_of_memory path
now.

[mhocko@kernel.org: oom_reap_task_mm should return false when __oom_reap_task_mm did]
Link: http://lkml.kernel.org/r/20180724141747.GP28386@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20180719075922.13784-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: David Rientjes <rientjes@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, oom: distinguish blockable mode for mmu notifiers

There are several blockable mmu notifiers which might sleep in
mmu_notifier_invalidate_range_start and that is a problem for the
oom_reaper because it needs to guarantee a forward progress so it cannot
depend on any sleepable locks.

Currently we simply back off and mark an oom victim with blockable mmu
notifiers as done after a short sleep.  That can result in selecting a new
oom victim prematurely because the previous one still hasn't torn its
memory down yet.

We can do much better though.  Even if mmu notifiers use sleepable locks
there is no reason to automatically assume those locks are held.  Moreover
majority of notifiers only care about a portion of the address space and
there is absolutely zero reason to fail when we are unmapping an unrelated
range.  Many notifiers do really block and wait for HW which is harder to
handle and we have to bail out though.

This patch handles the low hanging fruit.
__mmu_notifier_invalidate_range_start gets a blockable flag and callbacks
are not allowed to sleep if the flag is set to false.  This is achieved by
using trylock instead of the sleepable lock for most callbacks and
continue as long as we do not block down the call chain.

I think we can improve that even further because there is a common pattern
to do a range lookup first and then do something about that.  The first
part can be done without a sleeping lock in most cases AFAICS.

The oom_reaper end then simply retries if there is at least one notifier
which couldn't make any progress in !blockable mode.  A retry loop is
already implemented to wait for the mmap_sem and this is basically the
same thing.

The simplest way for driver developers to test this code path is to wrap
userspace code which uses these notifiers into a memcg and set the hard
limit to hit the oom.  This can be done e.g.  after the test faults in all
the mmu notifier managed memory and set the hard limit to something really
small.  Then we are looking for a proper process tear down.

[akpm@linux-foundation.org: coding style fixes]
[akpm@linux-foundation.org: minor code simplification]
Link: http://lkml.kernel.org/r/20180716115058.5559-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Christian König <christian.koenig@amd.com> # AMD notifiers
Acked-by: Leon Romanovsky <leonro@mellanox.com> # mlx and umem_odp
Reported-by: David Rientjes <rientjes@google.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>
Cc: Sudeep Dutt <sudeep.dutt@intel.com>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c: put_swap_page: share more between huge/normal code path

In this patch, locking related code is shared between huge/normal code
path in put_swap_page() to reduce code duplication. The `free_entries == 0`
case is merged into the more general `free_entries != SWAPFILE_CLUSTER`
case, because the new locking method makes it easy.

The added lines is same as the removed lines.  But the code size is
increased when CONFIG_TRANSPARENT_HUGEPAGE=n.

text    data     bss     dec     hex filename
base:        24123    2004     340   26467    6763 mm/swapfile.o
unified:       24485    2004     340   26829    68cd mm/swapfile.o

Dig on step deeper with `size -A mm/swapfile.o` for base and unified
kernel and compare the result, yields,

  -.text                                17723      0
  +.text                                17835      0
  -.orc_unwind_ip                        1380      0
  +.orc_unwind_ip                        1480      0
  -.orc_unwind                           2070      0
  +.orc_unwind                           2220      0
  -Total                                26686
  +Total                                27048

The total difference is the same.  The text segment difference is much
smaller: 112.  More difference comes from the ORC unwinder segments:
(1480 + 2220) - (1380 + 2070) = 250.  If the frame pointer unwinder is
used, this costs nothing.

Link: http://lkml.kernel.org/r/20180720071845.17920-9-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c: add __swap_entry_free_locked()

The part of __swap_entry_free() with lock held is separated into a new
function __swap_entry_free_locked().  Because we want to reuse that
piece of code in some other places.

Just mechanical code refactoring, there is no any functional change in
this function.

Link: http://lkml.kernel.org/r/20180720071845.17920-8-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, swap, get_swap_pages: use entry_size instead of cluster in parameter

As suggested by Matthew Wilcox, it is better to use "int entry_size"
instead of "bool cluster" as parameter to specify whether to operate for
huge or normal swap entries.  Because this improve the flexibility to
support other swap entry size.  And Dave Hansen thinks that this
improves code readability too.

So in this patch, the "bool cluster" parameter of get_swap_pages() is
replaced by "int entry_size".

And nr_swap_entries() trick is used to reduce the binary size when
!CONFIG_TRANSPARENT_HUGE_PAGE.

       text    data     bss     dec     hex filename
base  24215    2028     340   26583    67d7 mm/swapfile.o
head  24123    2004     340   26467    6763 mm/swapfile.o

Link: http://lkml.kernel.org/r/20180720071845.17920-7-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c: unify normal/huge code path in put_swap_page()

In this patch, the normal/huge code path in put_swap_page() and several
helper functions are unified to avoid duplicated code, bugs, etc.  and
make it easier to review the code.

The removed lines are more than added lines.  And the binary size is
kept exactly same when CONFIG_TRANSPARENT_HUGEPAGE=n.

Link: http://lkml.kernel.org/r/20180720071845.17920-6-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c: unify normal/huge code path in swap_page_trans_huge_swapped()

As suggested by Dave, we should unify the code path for normal and huge
swap support if possible to avoid duplicated code, bugs, etc.  and make
it easier to review code.

In this patch, the normal/huge code path in
swap_page_trans_huge_swapped() is unified, the added and removed lines
are same.  And the binary size is kept almost same when
CONFIG_TRANSPARENT_HUGEPAGE=n.

 text    data     bss     dec     hex filename
base: 24179    2028     340   26547    67b3 mm/swapfile.o
unified: 24215    2028     340   26583    67d7 mm/swapfile.o

Link: http://lkml.kernel.org/r/20180720071845.17920-5-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-and-acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c: use swap_count() in swap_page_trans_huge_swapped()

In swap_page_trans_huge_swapped(), to identify whether there's any page
table mapping for a 4k sized swap entry, "si->swap_map[i] !=
SWAP_HAS_CACHE" is used.  This works correctly now, because all users of
the function will only call it after checking SWAP_HAS_CACHE.  But as
pointed out by Daniel, it is better to use "swap_count(map[i])" here,
because it works for "map[i] == 0" case too.

And this makes the implementation more consistent between normal and
huge swap entry.

Link: http://lkml.kernel.org/r/20180720071845.17920-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-and-reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c: replace some #ifdef with IS_ENABLED()

In mm/swapfile.c, THP (Transparent Huge Page) swap specific code is
enclosed by #ifdef CONFIG_THP_SWAP/#endif to avoid code dilating when
THP isn't enabled.  But #ifdef/#endif in .c file hurt the code
readability, so Dave suggested to use IS_ENABLED(CONFIG_THP_SWAP)
instead and let compiler to do the dirty job for us.  This has potential
to remove some duplicated code too.  From output of `size`,

text    data     bss     dec     hex filename
THP=y:         26269    2076     340   28685    700d mm/swapfile.o
ifdef/endif:   24115    2028     340   26483    6773 mm/swapfile.o
IS_ENABLED:    24179    2028     340   26547    67b3 mm/swapfile.o

IS_ENABLED() based solution works quite well, almost as good as that of
#ifdef/#endif.  And from the diffstat, the removed lines are more than
added lines.

One #ifdef for split_swap_cluster() is kept.  Because it is a public
function with a stub implementation for CONFIG_THP_SWAP=n in swap.h.

Link: http://lkml.kernel.org/r/20180720071845.17920-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-and-acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: swap: add comments to lock_cluster_or_swap_info()

Patch series "swap: THP optimizing refactoring", v4.

Now the THP (Transparent Huge Page) swap optimizing is implemented in the
way like below,

  #ifdef CONFIG_THP_SWAP
  huge_function(...)
  {
  }
  #else
  normal_function(...)
  {
  }
  #endif

  general_function(...)
  {
   if (huge)
   return thp_function(...);
else
   return normal_function(...);
  }

As pointed out by Dave Hansen, this will,

1. Create a new, wholly untested code path for huge page
2. Create two places to patch bugs
3. Are not reusing code when possible

This patchset is to address these problems via merging huge/normal code
path/functions if possible.

One concern is that this may cause code size to dilate when
!CONFIG_TRANSPARENT_HUGEPAGE.  The data shows that most refactoring will
only cause quite slight code size increase.

This patch (of 8):

To improve code readability.

Link: http://lkml.kernel.org/r/20180720071845.17920-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-and-acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: struct shrinker: make flags of unsigned type

Currently, there are two flags only, so unsigned is more then enough.
Also, move int seeks to keep these fields together.

Link: http://lkml.kernel.org/r/153199748720.21131.6476256940113102483.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: struct shrink_control: keep int fields together

Patch series "Reorderings in struct shrinker and struct shrink_control".

These structures are intensively used during reclaim and, displace other
data in cache, so there is no a reason they have int fields not grouped
together.

This patch (of 2):

gfp_t is of unsigned type, so let's move nid to keep them together.

Link: http://lkml.kernel.org/r/153199747930.21131.861043607301997810.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: check shrinker is memcg-aware in register_shrinker_prepared()

There is a sad BUG introduced in patch adding SHRINKER_REGISTERING.
shrinker_idr business is only for memcg-aware shrinkers.  Only such type
of shrinkers have id and they must be finaly installed via idr_replace()
in this function.  For !memcg-aware shrinkers we never initialize
shrinker->id field.

But there are all types of shrinkers passed to idr_replace(), and every
!memcg-aware shrinker with random ID (most probably, its id is 0)
replaces memcg-aware shrinker pointed by the ID in IDR.

This patch fixes the problem.

Link: http://lkml.kernel.org/r/8ff8a793-8211-713a-4ed9-d6e52390c2fc@virtuozzo.com
Fixes: 7e010df53c80 "mm: use special value SHRINKER_REGISTERING instead of list_empty() check"
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reported-by: <syzbot+d5f648a1bfe15678786b@syzkaller.appspotmail.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <syzkaller-bugs@googlegroups.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

autofs: fix autofs_sbi() does not check super block type

autofs_sbi() does not check the superblock magic number to verify it has
been given an autofs super block.

Link: http://lkml.kernel.org/r/153475422934.17131.7563724552005298277.stgit@pluto.themaw.net
Reported-by: <syzbot+87c3c541582e56943277@syzkaller.appspotmail.com>
Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'please-pull-noboot' of git://git./linux/kernel/git/aegl/linux

Pull ia64 NO_BOOTMEM conversion from Tony Luck:
 "Mike Rapoport kindly fixed up ia64 to work with NO_BOOTMEM"

* tag 'please-pull-noboot' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  ia64: switch to NO_BOOTMEM
  ia64: use mem_data to detect nodes' minimal and maximal PFNs
  ia64: remove unused num_dma_physpages member from 'struct early_node_data'
  ia64: contig/paging_init: reduce code duplication

Merge tag 'linux-kselftest-4.19-rc1' of git://git./linux/kernel/git/shuah/linux-kselftest

Pull Kselftest update from Shuah Khan:

 - add cgroup core selftests

 - fix compile warnings in android ion test

 - fix to bugs in exclude and skip paths in vDSO test

 - remove obsolete config options

 - add missing .gitignore file

* tag 'linux-kselftest-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests/ftrace: Fix kprobe string testcase to not probe notrace function
  selftests: mount: remove no longer needed config option
  selftests: cgroup: add gitignore file
  Add cgroup core selftests
  selftests: vDSO - fix to return KSFT_SKIP when test couldn't be run
  selftests: vDSO - fix to exclude x86 test on non-x86 platforms
  selftests/android: initialize heap_type to avoid compiling warning

Merge tag 'trace-v4.19' of git://git./linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Restructure of lockdep and latency tracers

   This is the biggest change. Joel Fernandes restructured the hooks
   from irqs and preemption disabling and enabling. He got rid of a lot
   of the preprocessor #ifdef mess that they caused.

   He turned both lockdep and the latency tracers to use trace events
   inserted in the preempt/irqs disabling paths. But unfortunately,
   these started to cause issues in corner cases. Thus, parts of the
   code was reverted back to where lockdep and the latency tracers just
   get called directly (without using the trace events). But because the
   original change cleaned up the code very nicely we kept that, as well
   as the trace events for preempt and irqs disabling, but they are
   limited to not being called in NMIs.

 - Have trace events use SRCU for "rcu idle" calls. This was required
   for the preempt/irqs off trace events. But it also had to not allow
   them to be called in NMI context. Waiting till Paul makes an NMI safe
   SRCU API.

 - New notrace SRCU API to allow trace events to use SRCU.

 - Addition of mcount-nop option support

 - SPDX headers replacing GPL templates.

 - Various other fixes and clean ups.

 - Some fixes are marked for stable, but were not fully tested before
   the merge window opened.

* tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
  tracing: Fix SPDX format headers to use C++ style comments
  tracing: Add SPDX License format tags to tracing files
  tracing: Add SPDX License format to bpf_trace.c
  blktrace: Add SPDX License format header
  s390/ftrace: Add -mfentry and -mnop-mcount support
  tracing: Add -mcount-nop option support
  tracing: Avoid calling cc-option -mrecord-mcount for every Makefile
  tracing: Handle CC_FLAGS_FTRACE more accurately
  Uprobe: Additional argument arch_uprobe to uprobe_write_opcode()
  Uprobes: Simplify uprobe_register() body
  tracepoints: Free early tracepoints after RCU is initialized
  uprobes: Use synchronize_rcu() not synchronize_sched()
  tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()
  ftrace: Remove unused pointer ftrace_swapper_pid
  tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage"
  tracing/irqsoff: Handle preempt_count for different configs
  tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"
  tracing: irqsoff: Account for additional preempt_disable
  trace: Use rcu_dereference_raw for hooks from trace-event subsystem
  tracing/kprobes: Fix within_notrace_func() to check only notrace functions
  ...

Merge tag 'ceph-for-4.19-rc1' of git://github.com/ceph/ceph-client

Pull ceph updates from Ilya Dryomov:
 "The main things are support for cephx v2 authentication protocol and
  basic support for rbd images within namespaces (myself).

  Also included are y2038 conversion patches from Arnd, a pile of
  miscellaneous fixes from Chengguang and Zheng's feature bit
  infrastructure for the filesystem"

* tag 'ceph-for-4.19-rc1' of git://github.com/ceph/ceph-client: (40 commits)
  ceph: don't drop message if it contains more data than expected
  ceph: support cephfs' own feature bits
  crush: fix using plain integer as NULL warning
  libceph: remove unnecessary non NULL check for request_key
  ceph: refactor error handling code in ceph_reserve_caps()
  ceph: refactor ceph_unreserve_caps()
  ceph: change to void return type for __do_request()
  ceph: compare fsc->max_file_size and inode->i_size for max file size limit
  ceph: add additional size check in ceph_setattr()
  ceph: add additional offset check in ceph_write_iter()
  ceph: add additional range check in ceph_fallocate()
  ceph: add new field max_file_size in ceph_fs_client
  libceph: weaken sizeof check in ceph_x_verify_authorizer_reply()
  libceph: check authorizer reply/challenge length before reading
  libceph: implement CEPHX_V2 calculation mode
  libceph: add authorizer challenge
  libceph: factor out encrypt_authorizer()
  libceph: factor out __ceph_x_decrypt()
  libceph: factor out __prepare_write_connect()
  libceph: store ceph_auth_handshake pointer in ceph_connection
  ...

Merge tag 'rtc-4.19' of git://git./linux/kernel/git/abelloni/linux

Pull RTC updates from Alexandre Belloni:
 "It is now possible to add custom sysfs attributes while avoiding a
  possible race condition. Unused code has been removed resulting in a
  nice reduction of the code base. And more drivers have been switched
  to SPDX by their maintainers.

 Summary:

  Subsystem:
   - new helpers to add custom sysfs attributes
   - struct rtc_task removal along with rtc_irq_[un]register()
   - rtc_irq_set_state and rtc_irq_set_freq are not exported anymore

  Drivers:
   - armada38x: reset after rtc power loss
   - ds1307: now supports m41t11
   - isl1208: now supports isl1219 and tamper detection
   - pcf2127: internal SRAM support"

* tag 'rtc-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (34 commits)
  rtc: ds1307: simplify hwmon config
  rtc: s5m: Add SPDX license identifier
  rtc: maxim: Add SPDX license identifiers
  rtc: isl1219: add device tree documentation
  rtc: isl1208: set ev-evienb bit from device tree
  rtc: isl1208: Add "evdet" interrupt source for isl1219
  rtc: isl1208: add support for isl1219 with tamper detection
  rtc: sysfs: facilitate attribute add to rtc device
  rtc: remove struct rtc_task
  char: rtc: remove task handling
  rtc: pcf85063: preserve control register value between stop and start
  rtc: sh: remove unused variable rtc_dev
  rtc: unexport rtc_irq_set_*
  rtc: simplify rtc_irq_set_state/rtc_irq_set_freq
  rtc: remove irq_task and irq_task_lock
  rtc: remove rtc_irq_register/rtc_irq_unregister
  rtc: sh: remove dead code
  rtc: sa1100: don't set PIE frequency
  rtc: ds1307: support m41t11 variant
  rtc: ds1307: fix data pointer to m41t0
  ...

Merge branch 'for-linus' of git://git./linux/kernel/git/jikos/livepatching

Pull livepatching updates from Jiri Kosina:
 "Code cleanups from Kamalesh Babulal"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch: Validate module/old func name length
  livepatch: Remove reliable stacktrace check in klp_try_switch_task()

Merge branch 'for-linus' of git://git./linux/kernel/git/jikos/hid

Pull HID updates from Jiri Kosina:

 - touch_max detection improvements and quirk handling fixes in wacom
   driver from Jason Gerecke and Ping Cheng

 - Palm rejection from Dmitry Torokhov and _dial support from Benjamin
   Tissoires for hid-multitouch driver

 - Low voltage support for i2c-hid driver from Stephen Boyd

 - Guitar-Hero support from Nicolas Adenis-Lamarre

 - other assorted small fixes and device ID additions

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid: (40 commits)
  HID: intel_ish-hid: tx_buf memory leak on probe/remove
  HID: intel-ish-hid: Prevent loading of driver on Mehlow
  HID: cougar: Add support for the Cougar 500k Gaming Keyboard
  HID: cougar: make compare_device_paths reusable
  HID: intel-ish-hid: remove redundant variable num_frags
  HID: multitouch: handle palm for touchscreens
  HID: multitouch: touchscreens also use confidence reports
  HID: multitouch: report MT_TOOL_PALM for non-confident touches
  HID: microsoft: support the Surface Dial
  HID: core: do not upper bound the collection stack
  HID: input: enable Totem on the Dell Canvas 27
  HID: multitouch: remove one copy of values
  HID: multitouch: ditch mt_report_id
  HID: multitouch: store a per application quirks value
  HID: multitouch: Store per collection multitouch data
  HID: multitouch: make sure the static list of class is not changed
  input: add MT_TOOL_DIAL
  HID: elan: Add support for touchpad on the Toshiba Click Mini L9W
  HID: elan: Add USB-id for HP x2 10-n000nd touchpad
  HID: elan: Add a flag for selecting if the touchpad has a LED
  ...

Merge tag 'backlight-next-4.19' of git://git./linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "Core Framework:
   - Remove unused/obsolete code/comments

  New Functionality:
   - Allow less granular brightness specification for high-res PWMs; pwm_bl
   - Align brightness {inc,dec}rements with that perceived by the human-eye; pwm_bl

  Fix-ups:
   - Prepare for the introduction of -Wimplicit-fall-through; adp8860_bl

  Bug Fixes:
   - Fix uninitialised variable; pwm_bl"

* tag 'backlight-next-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: pwm_bl: Fix uninitialized variable
  backlight: adp8860: Mark expected switch fall-through
  backlight: Remove obsolete comment for ->state
  dt-bindings: pwm-backlight: Move brightness-levels to optional
  backlight: pwm_bl: Compute brightness of LED linearly to human eye
  dt-bindings: pwm-backlight: Add a num-interpolation-steps property
  backlight: pwm_bl: Linear interpolation between brightness-levels

Merge tag 'mfd-next-4.19' of git://git./linux/kernel/git/lee/mfd

Pull MFD updates from Lee Jones:
 "New Drivers:
   - Add Cirrus Logic Madera Codec (CS47L35, CS47L85 and CS47L90/91) driver
   - Add ChromeOS EC CEC driver
   - Add ROHM BD71837 PMIC driver

  New Device Support:
   - Add support for Dialog Semi DA9063L PMIC variant to DA9063
   - Add support for Intel Ice Lake to Intel-PLSS-PCI
   - Add support for X-Powers AXP806 to AXP20x

  New Functionality:
   - Add support for USB Charging to the ChromeOS Embedded Controller
   - Add support for HDMI CEC to the ChromeOS Embedded Controller
   - Add support for HDMI CEC to Intel HDMI
   - Add support for accessory detection to Madera devices
   - Allow individual pins to be configured via DT' wlf,csnaddr-pd
   - Provide legacy platform specific EEPROM/Watchdog commands; rave-sp

  Fix-upsL
   - Trivial renaming/spelling fixes; cros_ec, da9063-*
   - Convert to Managed Resources (devm_*); da9063-*, ti_am335x_tscadc
   - Transition to helper macros/functions; da9063-*
   - Constify; kempld-core
   - Improve error path/messages; wm8994-core
   - Disable IRQs locally instead of relying on USB subsystem; dln2
   - Remove unused code; rave-sp
   - New exports; sec-core

  Bug Fixes:
   - Fix possible false I2C transaction error; arizona-core
   - Fix declared memory area size; hi655x-pmic
   - Fix checksum type; rave-sp
   - Fix incorrect default serial port configuration: rave-sp
   - Fix incorrect coherent DMA mask for sub-devices; sm501"

* tag 'mfd-next-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd: (60 commits)
  mfd: madera: Add register definitions for accessory detect
  mfd: sm501: Set coherent_dma_mask when creating subdevices
  mfd: bd71837: Devicetree bindings for ROHM BD71837 PMIC
  mfd: bd71837: Core driver for ROHM BD71837 PMIC
  media: platform: cros-ec-cec: Fix dependency on MFD_CROS_EC
  mfd: sec-core: Export OF module alias table
  mfd: as3722: Disable auto-power-on when AC OK
  mfd: axp20x: Support AXP806 in I2C mode
  mfd: axp20x: Add self-working mode support for AXP806
  dt-bindings: mfd: axp20x: Add "self-working" mode for AXP806
  mfd: wm8994: Allow to configure CS/ADDR Pulldown from dts
  mfd: wm8994: Allow to configure Speaker Mode Pullup from dts
  mfd: rave-sp: Emulate CMD_GET_STATUS on device that don't support it
  mfd: rave-sp: Add legacy watchdog ping command translation
  mfd: rave-sp: Add legacy EEPROM access command translation
  mfd: rave-sp: Initialize flow control and parity of the port
  mfd: rave-sp: Fix incorrectly specified checksum type
  mfd: rave-sp: Remove unused defines
  mfd: hi655x: Fix regmap area declared size for hi655x
  mfd: ti_am335x_tscadc: Fix struct clk memory leak
  ...

Merge tag 'edac_fixes_for_4.19' of git://git./linux/kernel/git/bp/bp

Pull EDAC fix from Borislav Petkov:
 "An urgent fix for a NULL ptr deref on machines with LRDDR4 DIMMs, from
  Takashi Iwai"

* tag 'edac_fixes_for_4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp:
  EDAC: Add missing MEM_LRDDR4 entry in edac_mem_types[]

Raise the minimum required gcc version to 4.6

Various architectures fail to build properly with older versions of the
gcc compiler.

An example from Guenter Roeck in thread [1]:
>
>   In file included from ./include/linux/mm.h:17:0,
>                    from ./include/linux/pid_namespace.h:7,
>                    from ./include/linux/ptrace.h:10,
>                    from arch/openrisc/kernel/asm-offsets.c:32:
>   ./include/linux/mm_types.h:497:16: error: flexible array member in otherwise empty struct
>
> This is just an example with gcc 4.5.1 for or32. I have seen the problem
> with gcc 4.4 (for unicore32) as well.

So update the minimum required version of gcc to 4.6.

[1] https://lore.kernel.org/lkml/20180814170904.GA12768@roeck-us.net/

Miscellanea:

 - Update Documentation/process/changes.rst

 - Remove and consolidate version test blocks in compiler-gcc.h for
   versions lower than 4.6

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ia64: Fix kernel BUG at lib/ioremap.c:72!

Commit 0bbf47eab469 ("ia64: use asm-generic/io.h") results in a BUG
while booting ia64.  This is because asm-generic/io.h defines
PCI_IOBASE, which results in the function acpi_pci_root_remap_iospace()
doing a lot of unnecessary (and wrong) things.

I'd suggested an #if !CONFIG_IA64 in the functon, but Arnd suggested
keeping the fix inside the arch/ia64 tree.

Fixes: 0bbf47eab469 ("ia64: use asm-generic/io.h")
Suggested-by: Arnd Bergman <arnd@arndb.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'for-4.19/upstream' into for-linus

Merge branch 'for-4.19/wiimote' into for-linus

Guitar-Hero devices support for hid-wiimote

Merge branch 'for-4.19/wacom' into for-linus

Wacom driver updates:

- touch_max detection improvements
- quirk handling cleanup
- get rid of wacom custom usages

Merge branch 'for-4.19/upstream' into for-linus

Assorted small driver/core fixes.

Merge branch 'for-4.19/sony' into for-linus

devm_* API conversion for hid-sony

Merge branch 'for-4.19/multitouch-multiaxis' into for-linus

Multitouch updates:

- Dial support
- Palm rejection for touchscreens
- a few small assorted fixes

Merge branch 'for-4.19/intel-ish' into for-linus

Device-specific fixes for hid-intel-ish

Merge branch 'for-4.19/i2c-hid' into for-linus

Low voltage support for i2c-hid

Merge branch 'for-4.19/elan' into for-linus

Resolution/pressure fixes and new device support for hid-elan

Merge branch 'for-4.19/cougar' into for-linus

New device support for hid-cougar

Merge branch 'for-next' of git://git./linux/kernel/git/gerg/m68knommu

Pull m68knommu updates from Greg Ungerer:
 "Only two changes.

  One cleans up warnings in the ColdFire DMA code, the other stubs out
  (with warnings) ColdFire clock api functions not normally used"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  m68knommu: Fix typos in Coldfire 5272 DMA debug code
  m68k: coldfire: Normalize clk API

Merge git://git./linux/kernel/git/davem/net

Pull networking fixes from David Miller:

 1) Fix races in IPVS, from Tan Hu.

 2) Missing unbind in matchall classifier, from Hangbin Liu.

 3) Missing act_ife action release, from Vlad Buslov.

 4) Cure lockdep splats in ila, from Cong Wang.

 5) veth queue leak on link delete, from Toshiaki Makita.

 6) Disable isdn's IIOCDBGVAR ioctl, it exposes kernel addresses. From
    Kees Cook.

 7) RCU usage fixup in XDP, from Tariq Toukan.

 8) Two TCP ULP fixes from Daniel Borkmann.

 9) r8169 needs REALTEK_PHY as a Kconfig dependency, from Heiner
    Kallweit.

10) Always take tcf_lock with BH disabled, otherwise we can deadlock
    with rate estimator code paths. From Vlad Buslov.

11) Don't use MSI-X on RTL8106e r8169 chips, they don't resume properly.
    From Jian-Hong Pan.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (41 commits)
  ip6_vti: fix creating fallback tunnel device for vti6
  ip_vti: fix a null pointer deferrence when create vti fallback tunnel
  r8169: don't use MSI-X on RTL8106e
  net: lan743x_ptp: convert to ktime_get_clocktai_ts64
  net: sched: always disable bh when taking tcf_lock
  ip6_vti: simplify stats handling in vti6_xmit
  bpf: fix redirect to map under tail calls
  r8169: add missing Kconfig dependency
  tools/bpf: fix bpf selftest test_cgroup_storage failure
  bpf, sockmap: fix sock_map_ctx_update_elem race with exist/noexist
  bpf, sockmap: fix map elem deletion race with smap_stop_sock
  bpf, sockmap: fix leakage of smap_psock_map_entry
  tcp, ulp: fix leftover icsk_ulp_ops preventing sock from reattach
  tcp, ulp: add alias for all ulp modules
  bpf: fix a rcu usage warning in bpf_prog_array_copy_core()
  samples/bpf: all XDP samples should unload xdp/bpf prog on SIGTERM
  net/xdp: Fix suspicious RCU usage warning
  net/mlx5e: Delete unneeded function argument
  Documentation: networking: ti-cpsw: correct cbs parameters for Eth1 100Mb
  isdn: Disable IIOCDBGVAR
  ...

ip6_vti: fix creating fallback tunnel device for vti6

When set fb_tunnels_only_for_init_net to 1, don't create fallback tunnel
device for vti6 when a new namespace is created.

Tested:
[root@builder2 ~]# modprobe ip6_tunnel
[root@builder2 ~]# modprobe ip6_vti
[root@builder2 ~]# echo 1 > /proc/sys/net/core/fb_tunnels_only_for_init_net
[root@builder2 ~]# unshare -n
[root@builder2 ~]# ip link
1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT group
default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>