[PATCH] freepgt: remove MM_VM_SIZE(mm)

There's only one usage of MM_VM_SIZE(mm) left, and it's a troublesome macro
because mm doesn't contain the (32-bit emulation?) info needed.  But it too is
only needed because we ignore the end from the vma list.

We could make flush_pgtables return that end, or unmap_vmas.  Choose the
latter, since it's a natural fit with unmap_mapping_range_vma needing to know
its restart addr.  This does make more than minimal change, but if unmap_vmas
had returned the end before, this is how we'd have done it, rather than
storing the break_addr in zap_details.

unmap_vmas used to return count of vmas scanned, but that's just debug which
hasn't been useful in a while; and if we want the map_count 0 on exit check
back, it can easily come from the final remove_vm_struct loop.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/asm-ia64/processor.h b/include/asm-ia64/processor.h
index 8769dd9df3696030e11d69f5617403a69a178abd..2807f8d766d4c576c593d42834a3f56e2b999c4d 100644 (file)
--- a/include/asm-ia64/processor.h
+++ b/include/asm-ia64/processor.h
@@ -42,14 +42,6 @@
  */
 #define TASK_SIZE              (current->thread.task_size)
 
-/*
- * MM_VM_SIZE(mm) gives the maximum address (plus 1) which may contain a mapping for
- * address-space MM.  Note that with 32-bit tasks, this is still DEFAULT_TASK_SIZE,
- * because the kernel may have installed helper-mappings above TASK_SIZE.  For example,
- * for x86 emulation, the LDT and GDT are mapped above TASK_SIZE.
- */
-#define MM_VM_SIZE(mm)         DEFAULT_TASK_SIZE
-
 /*
  * This decides where the kernel will search for a free chunk of vm
  * space during mmap's.

diff --git a/include/asm-ppc64/processor.h b/include/asm-ppc64/processor.h
index cae65b30adb87ec9ecdfaa9179c9e2bc26e6bca7..0035efe2db2ba7591fce0f6be861e6f23b7ecfd6 100644 (file)
--- a/include/asm-ppc64/processor.h
+++ b/include/asm-ppc64/processor.h
@@ -542,10 +542,6 @@ extern struct task_struct *last_task_used_altivec;
 #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \
                TASK_SIZE_USER32 : TASK_SIZE_USER64)
 
-/* We can't actually tell the TASK_SIZE given just the mm, but default
- * to the 64-bit case to make sure that enough gets cleaned up. */
-#define MM_VM_SIZE(mm) TASK_SIZE_USER64
-
 /* This decides where the kernel will search for a free chunk of vm
  * space during mmap's.
  */

diff --git a/include/asm-s390/processor.h b/include/asm-s390/processor.h
index cbbd114716723729107014b56eda0eca3f043159..88c272ca48bf172297e1d32890b5cf1ef4720ec5 100644 (file)
--- a/include/asm-s390/processor.h
+++ b/include/asm-s390/processor.h
@@ -74,8 +74,6 @@ extern struct task_struct *last_task_used_math;
 
 #endif /* __s390x__ */
 
-#define MM_VM_SIZE(mm)         DEFAULT_TASK_SIZE
-
 #define HAVE_ARCH_PICK_MMAP_LAYOUT
 
 typedef struct {

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c3f6c39d41d010cb4d193288fa04c2a571cdb597..59eca28b5ae2d64d9d21a2b0cff152b47ca36152 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -37,10 +37,6 @@ extern int sysctl_legacy_va_layout;
 #include <asm/processor.h>
 #include <asm/atomic.h>
 
-#ifndef MM_VM_SIZE
-#define MM_VM_SIZE(mm) ((TASK_SIZE + PGDIR_SIZE - 1) & PGDIR_MASK)
-#endif
-
 #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
 
 /*
@@ -582,13 +578,12 @@ struct zap_details {
        pgoff_t first_index;                    /* Lowest page->index to unmap */
        pgoff_t last_index;                     /* Highest page->index to unmap */
        spinlock_t *i_mmap_lock;                /* For unmap_mapping_range: */
-       unsigned long break_addr;               /* Where unmap_vmas stopped */
        unsigned long truncate_count;           /* Compare vm_truncate_count */
 };
 
-void zap_page_range(struct vm_area_struct *vma, unsigned long address,
+unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
                unsigned long size, struct zap_details *);
-int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
+unsigned long unmap_vmas(struct mmu_gather **tlb, struct mm_struct *mm,
                struct vm_area_struct *start_vma, unsigned long start_addr,
                unsigned long end_addr, unsigned long *nr_accounted,
                struct zap_details *);

diff --git a/mm/memory.c b/mm/memory.c
index fee5dc8fc36c3bdea216890c56331d2c80599761..854bd90eeca1928b15dfb61088dd3d13360cb373 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -645,7 +645,7 @@ static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
  * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
  * @details: details of nonlinear truncation or shared cache invalidation
  *
- * Returns the number of vma's which were covered by the unmapping.
+ * Returns the end address of the unmapping (restart addr if interrupted).
  *
  * Unmap all pages in the vma list.  Called under page_table_lock.
  *
@@ -662,7 +662,7 @@ static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
  * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
  * drops the lock and schedules.
  */
-int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
+unsigned long unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
                struct vm_area_struct *vma, unsigned long start_addr,
                unsigned long end_addr, unsigned long *nr_accounted,
                struct zap_details *details)
@@ -670,12 +670,11 @@ int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
        unsigned long zap_bytes = ZAP_BLOCK_SIZE;
        unsigned long tlb_start = 0;    /* For tlb_finish_mmu */
        int tlb_start_valid = 0;
-       int ret = 0;
+       unsigned long start = start_addr;
        spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
        int fullmm = tlb_is_full_mm(*tlbp);
 
        for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
-               unsigned long start;
                unsigned long end;
 
                start = max(vma->vm_start, start_addr);
@@ -688,7 +687,6 @@ int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
                if (vma->vm_flags & VM_ACCOUNT)
                        *nr_accounted += (end - start) >> PAGE_SHIFT;
 
-               ret++;
                while (start != end) {
                        unsigned long block;
 
@@ -719,7 +717,6 @@ int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
                                if (i_mmap_lock) {
                                        /* must reset count of rss freed */
                                        *tlbp = tlb_gather_mmu(mm, fullmm);
-                                       details->break_addr = start;
                                        goto out;
                                }
                                spin_unlock(&mm->page_table_lock);
@@ -733,7 +730,7 @@ int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
                }
        }
 out:
-       return ret;
+       return start;   /* which is now the end (or restart) address */
 }
 
 /**
@@ -743,7 +740,7 @@ out:
  * @size: number of bytes to zap
  * @details: details of nonlinear truncation or shared cache invalidation
  */
-void zap_page_range(struct vm_area_struct *vma, unsigned long address,
+unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
                unsigned long size, struct zap_details *details)
 {
        struct mm_struct *mm = vma->vm_mm;
@@ -753,15 +750,16 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long address,
 
        if (is_vm_hugetlb_page(vma)) {
                zap_hugepage_range(vma, address, size);
-               return;
+               return end;
        }
 
        lru_add_drain();
        spin_lock(&mm->page_table_lock);
        tlb = tlb_gather_mmu(mm, 0);
-       unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
+       end = unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
        tlb_finish_mmu(tlb, address, end);
        spin_unlock(&mm->page_table_lock);
+       return end;
 }
 
 /*
@@ -1348,7 +1346,7 @@ no_new_page:
  * i_mmap_lock.
  *
  * In order to make forward progress despite repeatedly restarting some
- * large vma, note the break_addr set by unmap_vmas when it breaks out:
+ * large vma, note the restart_addr from unmap_vmas when it breaks out:
  * and restart from that address when we reach that vma again.  It might
  * have been split or merged, shrunk or extended, but never shifted: so
  * restart_addr remains valid so long as it remains in the vma's range.
@@ -1386,8 +1384,8 @@ again:
                }
        }
 
-       details->break_addr = end_addr;
-       zap_page_range(vma, start_addr, end_addr - start_addr, details);
+       restart_addr = zap_page_range(vma, start_addr,
+                                       end_addr - start_addr, details);
 
        /*
         * We cannot rely on the break test in unmap_vmas:
@@ -1398,14 +1396,14 @@ again:
        need_break = need_resched() ||
                        need_lockbreak(details->i_mmap_lock);
 
-       if (details->break_addr >= end_addr) {
+       if (restart_addr >= end_addr) {
                /* We have now completed this vma: mark it so */
                vma->vm_truncate_count = details->truncate_count;
                if (!need_break)
                        return 0;
        } else {
                /* Note restart_addr in vma's truncate_count field */
-               vma->vm_truncate_count = details->break_addr;
+               vma->vm_truncate_count = restart_addr;
                if (!need_break)
                        goto again;
        }

diff --git a/mm/mmap.c b/mm/mmap.c
index 926d030154712b8a8ddfc1b2b9c443ff55de27c2..f8c61b2385ff4100979927d8169240920a659d9b 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1900,6 +1900,7 @@ void exit_mmap(struct mm_struct *mm)
        struct mmu_gather *tlb;
        struct vm_area_struct *vma = mm->mmap;
        unsigned long nr_accounted = 0;
+       unsigned long end;
 
        lru_add_drain();
 
@@ -1908,10 +1909,10 @@ void exit_mmap(struct mm_struct *mm)
        flush_cache_mm(mm);
        tlb = tlb_gather_mmu(mm, 1);
        /* Use -1 here to ensure all VMAs in the mm are unmapped */
-       mm->map_count -= unmap_vmas(&tlb, mm, vma, 0, -1, &nr_accounted, NULL);
+       end = unmap_vmas(&tlb, mm, vma, 0, -1, &nr_accounted, NULL);
        vm_unacct_memory(nr_accounted);
        free_pgtables(&tlb, vma, 0, 0);
-       tlb_finish_mmu(tlb, 0, MM_VM_SIZE(mm));
+       tlb_finish_mmu(tlb, 0, end);
 
        mm->mmap = mm->mmap_cache = NULL;
        mm->mm_rb = RB_ROOT;
@@ -1931,7 +1932,6 @@ void exit_mmap(struct mm_struct *mm)
                vma = next;
        }
 
-       BUG_ON(mm->map_count);  /* This is just debugging */
        BUG_ON(mm->nr_ptes);    /* This is just debugging */
 }