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authorChristoph Lameter <clameter@sgi.com>2007-10-16 01:25:41 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 09:42:59 -0700
commit6cb062296f73e74768cca2f3eaf90deac54de02d (patch)
tree1572139653a6fc97cdffd06f2c1bfa650da2ce03 /mm/slub.c
parent58c0a4a7864b2dad6da4090813322fcd29a11c92 (diff)
downloadlwn-6cb062296f73e74768cca2f3eaf90deac54de02d.tar.gz
lwn-6cb062296f73e74768cca2f3eaf90deac54de02d.zip
Categorize GFP flags
The function of GFP_LEVEL_MASK seems to be unclear. In order to clear up the mystery we get rid of it and replace GFP_LEVEL_MASK with 3 sets of GFP flags: GFP_RECLAIM_MASK Flags used to control page allocator reclaim behavior. GFP_CONSTRAINT_MASK Flags used to limit where allocations can occur. GFP_SLAB_BUG_MASK Flags that the slab allocator BUG()s on. These replace the uses of GFP_LEVEL mask in the slab allocators and in vmalloc.c. The use of the flags not included in these sets may occur as a result of a slab allocation standing in for a page allocation when constructing scatter gather lists. Extraneous flags are cleared and not passed through to the page allocator. __GFP_MOVABLE/RECLAIMABLE, __GFP_COLD and __GFP_COMP will now be ignored if passed to a slab allocator. Change the allocation of allocator meta data in SLAB and vmalloc to not pass through flags listed in GFP_CONSTRAINT_MASK. SLAB already removes the __GFP_THISNODE flag for such allocations. Generalize that to also cover vmalloc. The use of GFP_CONSTRAINT_MASK also includes __GFP_HARDWALL. The impact of allocator metadata placement on access latency to the cachelines of the object itself is minimal since metadata is only referenced on alloc and free. The attempt is still made to place the meta data optimally but we consistently allow fallback both in SLAB and vmalloc (SLUB does not need to allocate metadata like that). Allocator metadata may serve multiple in kernel users and thus should not be subject to the limitations arising from a single allocation context. [akpm@linux-foundation.org: fix fallback_alloc()] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 968ce3776e08..19d3202ca2dc 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1088,12 +1088,13 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
void *last;
void *p;
- BUG_ON(flags & ~(GFP_DMA | __GFP_ZERO | GFP_LEVEL_MASK));
+ BUG_ON(flags & GFP_SLAB_BUG_MASK);
if (flags & __GFP_WAIT)
local_irq_enable();
- page = allocate_slab(s, flags & GFP_LEVEL_MASK, node);
+ page = allocate_slab(s,
+ flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
if (!page)
goto out;