From b3b9c2932c32e0692018ed5f12f3fd8c70eea8ce Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Mon, 8 Oct 2012 16:28:34 -0700 Subject: [PATCH] mm, x86, pat: rework linear pfn-mmap tracking Replace the generic vma-flag VM_PFN_AT_MMAP with x86-only VM_PAT. We can toss mapping address from remap_pfn_range() into track_pfn_vma_new(), and collect all PAT-related logic together in arch/x86/. This patch also restores orignal frustration-free is_cow_mapping() check in remap_pfn_range(), as it was before commit v2.6.28-rc8-88-g3c8bb73 ("x86: PAT: store vm_pgoff for all linear_over_vma_region mappings - v3") is_linear_pfn_mapping() checks can be removed from mm/huge_memory.c, because it already handled by VM_PFNMAP in VM_NO_THP bit-mask. [suresh.b.siddha@intel.com: Reset the VM_PAT flag as part of untrack_pfn_vma()] Signed-off-by: Konstantin Khlebnikov Signed-off-by: Suresh Siddha Cc: Venkatesh Pallipadi Cc: H. Peter Anvin Cc: Nick Piggin Cc: Ingo Molnar Cc: Alexander Viro Cc: Carsten Otte Cc: Chris Metcalf Cc: Cyrill Gorcunov Cc: Eric Paris Cc: Hugh Dickins Cc: James Morris Cc: Jason Baron Cc: Kentaro Takeda Cc: Matt Helsley Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Robert Richter Cc: Tetsuo Handa Cc: Venkatesh Pallipadi Acked-by: Linus Torvalds Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/mm/pat.c | 17 ++++++++++++----- include/asm-generic/pgtable.h | 6 ++++-- include/linux/mm.h | 20 +------------------- mm/huge_memory.c | 19 +++---------------- mm/memory.c | 26 ++++++++++---------------- 5 files changed, 30 insertions(+), 58 deletions(-) diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 74a702674e86..0eb572eda406 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -677,7 +677,7 @@ int track_pfn_copy(struct vm_area_struct *vma) unsigned long vma_size = vma->vm_end - vma->vm_start; pgprot_t pgprot; - if (is_linear_pfn_mapping(vma)) { + if (vma->vm_flags & VM_PAT) { /* * reserve the whole chunk covered by vma. We need the * starting address and protection from pte. @@ -699,14 +699,20 @@ int track_pfn_copy(struct vm_area_struct *vma) * single reserve_pfn_range call. */ int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot, - unsigned long pfn, unsigned long size) + unsigned long pfn, unsigned long addr, unsigned long size) { resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT; unsigned long flags; /* reserve the whole chunk starting from paddr */ - if (is_linear_pfn_mapping(vma)) - return reserve_pfn_range(paddr, size, prot, 0); + if (addr == vma->vm_start && size == (vma->vm_end - vma->vm_start)) { + int ret; + + ret = reserve_pfn_range(paddr, size, prot, 0); + if (!ret) + vma->vm_flags |= VM_PAT; + return ret; + } if (!pat_enabled) return 0; @@ -758,7 +764,7 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, resource_size_t paddr; unsigned long prot; - if (!is_linear_pfn_mapping(vma)) + if (!(vma->vm_flags & VM_PAT)) return; /* free the chunk starting from pfn or the whole chunk */ @@ -772,6 +778,7 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, size = vma->vm_end - vma->vm_start; } free_pfn_range(paddr, size); + vma->vm_flags &= ~VM_PAT; } pgprot_t pgprot_writecombine(pgprot_t prot) diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index d4d4592c97fc..c9a612069c8e 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -391,7 +391,8 @@ static inline void ptep_modify_prot_commit(struct mm_struct *mm, * by remap_pfn_range() for physical range indicated by pfn and size. */ static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot, - unsigned long pfn, unsigned long size) + unsigned long pfn, unsigned long addr, + unsigned long size) { return 0; } @@ -426,7 +427,8 @@ static inline void untrack_pfn(struct vm_area_struct *vma, } #else extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot, - unsigned long pfn, unsigned long size); + unsigned long pfn, unsigned long addr, + unsigned long size); extern int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, unsigned long pfn); extern int track_pfn_copy(struct vm_area_struct *vma); diff --git a/include/linux/mm.h b/include/linux/mm.h index 311be906b57d..75d1632d3477 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -117,7 +117,7 @@ extern unsigned int kobjsize(const void *objp); #define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */ #define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */ #define VM_SAO 0x20000000 /* Strong Access Ordering (powerpc) */ -#define VM_PFN_AT_MMAP 0x40000000 /* PFNMAP vma that is fully mapped at mmap time */ +#define VM_PAT 0x40000000 /* PAT reserves whole VMA at once (x86) */ #define VM_MERGEABLE 0x80000000 /* KSM may merge identical pages */ /* Bits set in the VMA until the stack is in its final location */ @@ -158,24 +158,6 @@ extern pgprot_t protection_map[16]; #define FAULT_FLAG_RETRY_NOWAIT 0x10 /* Don't drop mmap_sem and wait when retrying */ #define FAULT_FLAG_KILLABLE 0x20 /* The fault task is in SIGKILL killable region */ -/* - * This interface is used by x86 PAT code to identify a pfn mapping that is - * linear over entire vma. This is to optimize PAT code that deals with - * marking the physical region with a particular prot. This is not for generic - * mm use. Note also that this check will not work if the pfn mapping is - * linear for a vma starting at physical address 0. In which case PAT code - * falls back to slow path of reserving physical range page by page. - */ -static inline int is_linear_pfn_mapping(struct vm_area_struct *vma) -{ - return !!(vma->vm_flags & VM_PFN_AT_MMAP); -} - -static inline int is_pfn_mapping(struct vm_area_struct *vma) -{ - return !!(vma->vm_flags & VM_PFNMAP); -} - /* * vm_fault is filled by the the pagefault handler and passed to the vma's * ->fault function. The vma's ->fault is responsible for returning a bitmask diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 141dbb695097..73cb22ee9665 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1655,11 +1655,7 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma) if (vma->vm_ops) /* khugepaged not yet working on file or special mappings */ return 0; - /* - * If is_pfn_mapping() is true is_learn_pfn_mapping() must be - * true too, verify it here. - */ - VM_BUG_ON(is_linear_pfn_mapping(vma) || vma->vm_flags & VM_NO_THP); + VM_BUG_ON(vma->vm_flags & VM_NO_THP); hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK; if (hstart < hend) @@ -1912,11 +1908,7 @@ static void collapse_huge_page(struct mm_struct *mm, goto out; if (is_vma_temporary_stack(vma)) goto out; - /* - * If is_pfn_mapping() is true is_learn_pfn_mapping() must be - * true too, verify it here. - */ - VM_BUG_ON(is_linear_pfn_mapping(vma) || vma->vm_flags & VM_NO_THP); + VM_BUG_ON(vma->vm_flags & VM_NO_THP); pgd = pgd_offset(mm, address); if (!pgd_present(*pgd)) @@ -2154,12 +2146,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, goto skip; if (is_vma_temporary_stack(vma)) goto skip; - /* - * If is_pfn_mapping() is true is_learn_pfn_mapping() - * must be true too, verify it here. - */ - VM_BUG_ON(is_linear_pfn_mapping(vma) || - vma->vm_flags & VM_NO_THP); + VM_BUG_ON(vma->vm_flags & VM_NO_THP); hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK; diff --git a/mm/memory.c b/mm/memory.c index 6bef278ad303..655e1429388a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1055,7 +1055,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, if (is_vm_hugetlb_page(vma)) return copy_hugetlb_page_range(dst_mm, src_mm, vma); - if (unlikely(is_pfn_mapping(vma))) { + if (unlikely(vma->vm_flags & VM_PFNMAP)) { /* * We do not free on error cases below as remove_vma * gets called on error from higher level routine @@ -1327,7 +1327,7 @@ static void unmap_single_vma(struct mmu_gather *tlb, if (vma->vm_file) uprobe_munmap(vma, start, end); - if (unlikely(is_pfn_mapping(vma))) + if (unlikely(vma->vm_flags & VM_PFNMAP)) untrack_pfn(vma, 0, 0); if (start != end) { @@ -2299,26 +2299,20 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, * There's a horrible special case to handle copy-on-write * behaviour that some programs depend on. We mark the "original" * un-COW'ed pages by matching them up with "vma->vm_pgoff". + * See vm_normal_page() for details. */ - if (addr == vma->vm_start && end == vma->vm_end) { + if (is_cow_mapping(vma->vm_flags)) { + if (addr != vma->vm_start || end != vma->vm_end) + return -EINVAL; vma->vm_pgoff = pfn; - vma->vm_flags |= VM_PFN_AT_MMAP; - } else if (is_cow_mapping(vma->vm_flags)) + } + + err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); + if (err) return -EINVAL; vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; - err = track_pfn_remap(vma, &prot, pfn, PAGE_ALIGN(size)); - if (err) { - /* - * To indicate that track_pfn related cleanup is not - * needed from higher level routine calling unmap_vmas - */ - vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP); - vma->vm_flags &= ~VM_PFN_AT_MMAP; - return -EINVAL; - } - BUG_ON(addr >= end); pfn -= addr >> PAGE_SHIFT; pgd = pgd_offset(mm, addr); -- 2.30.2