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author | David Howells <dhowells@redhat.com> | 2009-04-02 16:56:32 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-02 19:04:48 -0700 |
commit | 33e5d76979cf01e3834814fe0aea569d1d602c1a (patch) | |
tree | 58a03e5da59db203245da10db144a4f6f61a83ba /mm/nommu.c | |
parent | 5482415a5ecc0cd791a5d885cc3db8281401078f (diff) | |
download | blackbird-op-linux-33e5d76979cf01e3834814fe0aea569d1d602c1a.tar.gz blackbird-op-linux-33e5d76979cf01e3834814fe0aea569d1d602c1a.zip |
nommu: fix a number of issues with the per-MM VMA patch
Fix a number of issues with the per-MM VMA patch:
(1) Make mmap_pages_allocated an atomic_long_t, just in case this is used on
a NOMMU system with more than 2G pages. Makes no difference on a 32-bit
system.
(2) Report vma->vm_pgoff * PAGE_SIZE as a 64-bit value, not a 32-bit value,
lest it overflow.
(3) Move the allocation of the vm_area_struct slab back for fork.c.
(4) Use KMEM_CACHE() for both vm_area_struct and vm_region slabs.
(5) Use BUG_ON() rather than if () BUG().
(6) Make the default validate_nommu_regions() a static inline rather than a
#define.
(7) Make free_page_series()'s objection to pages with a refcount != 1 more
informative.
(8) Adjust the __put_nommu_region() banner comment to indicate that the
semaphore must be held for writing.
(9) Limit the number of warnings about munmaps of non-mmapped regions.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/nommu.c')
-rw-r--r-- | mm/nommu.c | 52 |
1 files changed, 25 insertions, 27 deletions
diff --git a/mm/nommu.c b/mm/nommu.c index 2fcf47d449b4..72eda4aee2cb 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -69,7 +69,7 @@ int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; int sysctl_nr_trim_pages = 1; /* page trimming behaviour */ int heap_stack_gap = 0; -atomic_t mmap_pages_allocated; +atomic_long_t mmap_pages_allocated; EXPORT_SYMBOL(mem_map); EXPORT_SYMBOL(num_physpages); @@ -463,12 +463,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) */ void __init mmap_init(void) { - vm_region_jar = kmem_cache_create("vm_region_jar", - sizeof(struct vm_region), 0, - SLAB_PANIC, NULL); - vm_area_cachep = kmem_cache_create("vm_area_struct", - sizeof(struct vm_area_struct), 0, - SLAB_PANIC, NULL); + vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC); } /* @@ -486,27 +481,24 @@ static noinline void validate_nommu_regions(void) return; last = rb_entry(lastp, struct vm_region, vm_rb); - if (unlikely(last->vm_end <= last->vm_start)) - BUG(); - if (unlikely(last->vm_top < last->vm_end)) - BUG(); + BUG_ON(unlikely(last->vm_end <= last->vm_start)); + BUG_ON(unlikely(last->vm_top < last->vm_end)); while ((p = rb_next(lastp))) { region = rb_entry(p, struct vm_region, vm_rb); last = rb_entry(lastp, struct vm_region, vm_rb); - if (unlikely(region->vm_end <= region->vm_start)) - BUG(); - if (unlikely(region->vm_top < region->vm_end)) - BUG(); - if (unlikely(region->vm_start < last->vm_top)) - BUG(); + BUG_ON(unlikely(region->vm_end <= region->vm_start)); + BUG_ON(unlikely(region->vm_top < region->vm_end)); + BUG_ON(unlikely(region->vm_start < last->vm_top)); lastp = p; } } #else -#define validate_nommu_regions() do {} while(0) +static void validate_nommu_regions(void) +{ +} #endif /* @@ -563,16 +555,17 @@ static void free_page_series(unsigned long from, unsigned long to) struct page *page = virt_to_page(from); kdebug("- free %lx", from); - atomic_dec(&mmap_pages_allocated); + atomic_long_dec(&mmap_pages_allocated); if (page_count(page) != 1) - kdebug("free page %p [%d]", page, page_count(page)); + kdebug("free page %p: refcount not one: %d", + page, page_count(page)); put_page(page); } } /* * release a reference to a region - * - the caller must hold the region semaphore, which this releases + * - the caller must hold the region semaphore for writing, which this releases * - the region may not have been added to the tree yet, in which case vm_top * will equal vm_start */ @@ -1096,7 +1089,7 @@ static int do_mmap_private(struct vm_area_struct *vma, goto enomem; total = 1 << order; - atomic_add(total, &mmap_pages_allocated); + atomic_long_add(total, &mmap_pages_allocated); point = rlen >> PAGE_SHIFT; @@ -1107,7 +1100,7 @@ static int do_mmap_private(struct vm_area_struct *vma, order = ilog2(total - point); n = 1 << order; kdebug("shave %lu/%lu @%lu", n, total - point, total); - atomic_sub(n, &mmap_pages_allocated); + atomic_long_sub(n, &mmap_pages_allocated); total -= n; set_page_refcounted(pages + total); __free_pages(pages + total, order); @@ -1536,10 +1529,15 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) /* find the first potentially overlapping VMA */ vma = find_vma(mm, start); if (!vma) { - printk(KERN_WARNING - "munmap of memory not mmapped by process %d (%s):" - " 0x%lx-0x%lx\n", - current->pid, current->comm, start, start + len - 1); + static int limit = 0; + if (limit < 5) { + printk(KERN_WARNING + "munmap of memory not mmapped by process %d" + " (%s): 0x%lx-0x%lx\n", + current->pid, current->comm, + start, start + len - 1); + limit++; + } return -EINVAL; } |