slub: record page flag overlays explicitly
SLUB reuses two page bits for internal purposes, it overlays PG_active and PG_error. This is hidden away in slub.c. Document these overlays explicitly in the main page-flags enum along with all the others. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0cad47cf13
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8a38082d21
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@ -104,6 +104,10 @@ enum pageflags {
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/* XEN */
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PG_pinned = PG_owner_priv_1,
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PG_savepinned = PG_dirty,
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/* SLUB */
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PG_slub_frozen = PG_active,
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PG_slub_debug = PG_error,
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};
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#ifndef __GENERATING_BOUNDS_H
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@ -169,6 +173,9 @@ PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
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PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private)
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__SETPAGEFLAG(Private, private)
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__PAGEFLAG(SlubFrozen, slub_frozen)
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__PAGEFLAG(SlubDebug, slub_debug)
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/*
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* Only test-and-set exist for PG_writeback. The unconditional operators are
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* risky: they bypass page accounting.
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65
mm/slub.c
65
mm/slub.c
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@ -102,44 +102,12 @@
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* the fast path and disables lockless freelists.
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*/
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#define FROZEN (1 << PG_active)
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#ifdef CONFIG_SLUB_DEBUG
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#define SLABDEBUG (1 << PG_error)
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#define SLABDEBUG 1
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#else
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#define SLABDEBUG 0
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#endif
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static inline int SlabFrozen(struct page *page)
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{
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return page->flags & FROZEN;
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}
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static inline void SetSlabFrozen(struct page *page)
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{
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page->flags |= FROZEN;
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}
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static inline void ClearSlabFrozen(struct page *page)
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{
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page->flags &= ~FROZEN;
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}
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static inline int SlabDebug(struct page *page)
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{
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return page->flags & SLABDEBUG;
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}
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static inline void SetSlabDebug(struct page *page)
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{
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page->flags |= SLABDEBUG;
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}
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static inline void ClearSlabDebug(struct page *page)
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{
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page->flags &= ~SLABDEBUG;
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}
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/*
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* Issues still to be resolved:
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*
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@ -971,7 +939,7 @@ static int free_debug_processing(struct kmem_cache *s, struct page *page,
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}
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/* Special debug activities for freeing objects */
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if (!SlabFrozen(page) && !page->freelist)
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if (!PageSlubFrozen(page) && !page->freelist)
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remove_full(s, page);
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if (s->flags & SLAB_STORE_USER)
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set_track(s, object, TRACK_FREE, addr);
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@ -1157,7 +1125,7 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
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page->flags |= 1 << PG_slab;
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if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
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SLAB_STORE_USER | SLAB_TRACE))
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SetSlabDebug(page);
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__SetPageSlubDebug(page);
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start = page_address(page);
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@ -1184,14 +1152,14 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
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int order = compound_order(page);
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int pages = 1 << order;
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if (unlikely(SlabDebug(page))) {
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if (unlikely(SLABDEBUG && PageSlubDebug(page))) {
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void *p;
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slab_pad_check(s, page);
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for_each_object(p, s, page_address(page),
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page->objects)
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check_object(s, page, p, 0);
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ClearSlabDebug(page);
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__ClearPageSlubDebug(page);
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}
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mod_zone_page_state(page_zone(page),
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@ -1288,7 +1256,7 @@ static inline int lock_and_freeze_slab(struct kmem_cache_node *n,
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if (slab_trylock(page)) {
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list_del(&page->lru);
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n->nr_partial--;
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SetSlabFrozen(page);
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__SetPageSlubFrozen(page);
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return 1;
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}
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return 0;
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@ -1398,7 +1366,7 @@ static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail)
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struct kmem_cache_node *n = get_node(s, page_to_nid(page));
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struct kmem_cache_cpu *c = get_cpu_slab(s, smp_processor_id());
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ClearSlabFrozen(page);
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__ClearPageSlubFrozen(page);
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if (page->inuse) {
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if (page->freelist) {
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@ -1406,7 +1374,8 @@ static void unfreeze_slab(struct kmem_cache *s, struct page *page, int tail)
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stat(c, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
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} else {
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stat(c, DEACTIVATE_FULL);
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if (SlabDebug(page) && (s->flags & SLAB_STORE_USER))
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if (SLABDEBUG && PageSlubDebug(page) &&
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(s->flags & SLAB_STORE_USER))
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add_full(n, page);
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}
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slab_unlock(page);
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@ -1551,7 +1520,7 @@ load_freelist:
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object = c->page->freelist;
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if (unlikely(!object))
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goto another_slab;
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if (unlikely(SlabDebug(c->page)))
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if (unlikely(SLABDEBUG && PageSlubDebug(c->page)))
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goto debug;
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c->freelist = object[c->offset];
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@ -1588,7 +1557,7 @@ new_slab:
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if (c->page)
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flush_slab(s, c);
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slab_lock(new);
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SetSlabFrozen(new);
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__SetPageSlubFrozen(new);
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c->page = new;
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goto load_freelist;
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}
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@ -1674,7 +1643,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
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stat(c, FREE_SLOWPATH);
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slab_lock(page);
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if (unlikely(SlabDebug(page)))
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if (unlikely(SLABDEBUG && PageSlubDebug(page)))
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goto debug;
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checks_ok:
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@ -1682,7 +1651,7 @@ checks_ok:
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page->freelist = object;
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page->inuse--;
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if (unlikely(SlabFrozen(page))) {
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if (unlikely(PageSlubFrozen(page))) {
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stat(c, FREE_FROZEN);
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goto out_unlock;
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}
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@ -3317,12 +3286,12 @@ static void validate_slab_slab(struct kmem_cache *s, struct page *page,
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s->name, page);
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if (s->flags & DEBUG_DEFAULT_FLAGS) {
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if (!SlabDebug(page))
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printk(KERN_ERR "SLUB %s: SlabDebug not set "
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if (!PageSlubDebug(page))
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printk(KERN_ERR "SLUB %s: SlubDebug not set "
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"on slab 0x%p\n", s->name, page);
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} else {
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if (SlabDebug(page))
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printk(KERN_ERR "SLUB %s: SlabDebug set on "
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if (PageSlubDebug(page))
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printk(KERN_ERR "SLUB %s: SlubDebug set on "
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"slab 0x%p\n", s->name, page);
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}
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}
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