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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>
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parent
5482415a5e
commit
33e5d76979
6 changed files with 30 additions and 34 deletions
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@ -120,7 +120,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
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K(i.freeram-i.freehigh),
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#endif
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#ifndef CONFIG_MMU
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K((unsigned long) atomic_read(&mmap_pages_allocated)),
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K((unsigned long) atomic_long_read(&mmap_pages_allocated)),
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#endif
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K(i.totalswap),
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K(i.freeswap),
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@ -136,14 +136,14 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
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}
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seq_printf(m,
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"%08lx-%08lx %c%c%c%c %08lx %02x:%02x %lu %n",
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"%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
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vma->vm_start,
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vma->vm_end,
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flags & VM_READ ? 'r' : '-',
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flags & VM_WRITE ? 'w' : '-',
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flags & VM_EXEC ? 'x' : '-',
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flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
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vma->vm_pgoff << PAGE_SHIFT,
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(unsigned long long) vma->vm_pgoff << PAGE_SHIFT,
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MAJOR(dev), MINOR(dev), ino, &len);
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if (file) {
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@ -1079,7 +1079,7 @@ static inline void setup_per_cpu_pageset(void) {}
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#endif
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/* nommu.c */
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extern atomic_t mmap_pages_allocated;
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extern atomic_long_t mmap_pages_allocated;
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/* prio_tree.c */
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void vma_prio_tree_add(struct vm_area_struct *, struct vm_area_struct *old);
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@ -1488,6 +1488,7 @@ void __init proc_caches_init(void)
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mm_cachep = kmem_cache_create("mm_struct",
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sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
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SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
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vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC);
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mmap_init();
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}
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@ -2481,7 +2481,4 @@ void mm_drop_all_locks(struct mm_struct *mm)
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*/
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void __init mmap_init(void)
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{
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vm_area_cachep = kmem_cache_create("vm_area_struct",
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sizeof(struct vm_area_struct), 0,
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SLAB_PANIC, NULL);
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}
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52
mm/nommu.c
52
mm/nommu.c
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@ -69,7 +69,7 @@ int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
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int sysctl_nr_trim_pages = 1; /* page trimming behaviour */
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int heap_stack_gap = 0;
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atomic_t mmap_pages_allocated;
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atomic_long_t mmap_pages_allocated;
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EXPORT_SYMBOL(mem_map);
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EXPORT_SYMBOL(num_physpages);
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@ -463,12 +463,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
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*/
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void __init mmap_init(void)
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{
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vm_region_jar = kmem_cache_create("vm_region_jar",
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sizeof(struct vm_region), 0,
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SLAB_PANIC, NULL);
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vm_area_cachep = kmem_cache_create("vm_area_struct",
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sizeof(struct vm_area_struct), 0,
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SLAB_PANIC, NULL);
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vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
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}
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/*
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@ -486,27 +481,24 @@ static noinline void validate_nommu_regions(void)
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return;
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last = rb_entry(lastp, struct vm_region, vm_rb);
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if (unlikely(last->vm_end <= last->vm_start))
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BUG();
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if (unlikely(last->vm_top < last->vm_end))
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BUG();
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BUG_ON(unlikely(last->vm_end <= last->vm_start));
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BUG_ON(unlikely(last->vm_top < last->vm_end));
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while ((p = rb_next(lastp))) {
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region = rb_entry(p, struct vm_region, vm_rb);
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last = rb_entry(lastp, struct vm_region, vm_rb);
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if (unlikely(region->vm_end <= region->vm_start))
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BUG();
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if (unlikely(region->vm_top < region->vm_end))
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BUG();
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if (unlikely(region->vm_start < last->vm_top))
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BUG();
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BUG_ON(unlikely(region->vm_end <= region->vm_start));
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BUG_ON(unlikely(region->vm_top < region->vm_end));
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BUG_ON(unlikely(region->vm_start < last->vm_top));
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lastp = p;
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}
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}
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#else
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#define validate_nommu_regions() do {} while(0)
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static void validate_nommu_regions(void)
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{
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}
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#endif
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/*
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@ -563,16 +555,17 @@ static void free_page_series(unsigned long from, unsigned long to)
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struct page *page = virt_to_page(from);
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kdebug("- free %lx", from);
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atomic_dec(&mmap_pages_allocated);
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atomic_long_dec(&mmap_pages_allocated);
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if (page_count(page) != 1)
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kdebug("free page %p [%d]", page, page_count(page));
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kdebug("free page %p: refcount not one: %d",
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page, page_count(page));
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put_page(page);
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}
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}
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/*
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* release a reference to a region
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* - the caller must hold the region semaphore, which this releases
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* - the caller must hold the region semaphore for writing, which this releases
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* - the region may not have been added to the tree yet, in which case vm_top
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* will equal vm_start
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*/
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@ -1096,7 +1089,7 @@ static int do_mmap_private(struct vm_area_struct *vma,
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goto enomem;
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total = 1 << order;
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atomic_add(total, &mmap_pages_allocated);
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atomic_long_add(total, &mmap_pages_allocated);
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point = rlen >> PAGE_SHIFT;
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@ -1107,7 +1100,7 @@ static int do_mmap_private(struct vm_area_struct *vma,
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order = ilog2(total - point);
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n = 1 << order;
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kdebug("shave %lu/%lu @%lu", n, total - point, total);
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atomic_sub(n, &mmap_pages_allocated);
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atomic_long_sub(n, &mmap_pages_allocated);
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total -= n;
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set_page_refcounted(pages + total);
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__free_pages(pages + total, order);
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@ -1536,10 +1529,15 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
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/* find the first potentially overlapping VMA */
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vma = find_vma(mm, start);
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if (!vma) {
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printk(KERN_WARNING
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"munmap of memory not mmapped by process %d (%s):"
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" 0x%lx-0x%lx\n",
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current->pid, current->comm, start, start + len - 1);
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static int limit = 0;
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if (limit < 5) {
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printk(KERN_WARNING
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"munmap of memory not mmapped by process %d"
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" (%s): 0x%lx-0x%lx\n",
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current->pid, current->comm,
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start, start + len - 1);
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limit++;
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}
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return -EINVAL;
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}
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