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authorLinus Torvalds <torvalds@g5.osdl.org>2006-03-07 02:44:43 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-07 02:44:43 +0100
commit9888e6fa7b68d9c8cc2c162a90979825ab45150a (patch)
tree83e46fb733008fa753269d338f90ad255cc59f53 /mm/slab.c
parentAllocate 96 bytes for SCSI sense data reply (diff)
downloadlinux-9888e6fa7b68d9c8cc2c162a90979825ab45150a.tar.xz
linux-9888e6fa7b68d9c8cc2c162a90979825ab45150a.zip
slab: clarify and fix calculate_slab_order()
If we triggered the 'offslab_limit' test, we would return with cachep->gfporder incremented once too many times. This clarifies the logic somewhat, and fixes that bug. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/slab.c')
-rw-r--r--mm/slab.c24
1 files changed, 12 insertions, 12 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 2b0b1519bb74..f2e92dc1c9ce 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1628,36 +1628,36 @@ static inline size_t calculate_slab_order(struct kmem_cache *cachep,
size_t size, size_t align, unsigned long flags)
{
size_t left_over = 0;
+ int gfporder;
- for (;; cachep->gfporder++) {
+ for (gfporder = 0 ; gfporder <= MAX_GFP_ORDER; gfporder++) {
unsigned int num;
size_t remainder;
- if (cachep->gfporder > MAX_GFP_ORDER) {
- cachep->num = 0;
- break;
- }
-
- cache_estimate(cachep->gfporder, size, align, flags,
- &remainder, &num);
+ cache_estimate(gfporder, size, align, flags, &remainder, &num);
if (!num)
continue;
+
/* More than offslab_limit objects will cause problems */
- if (flags & CFLGS_OFF_SLAB && cachep->num > offslab_limit)
+ if ((flags & CFLGS_OFF_SLAB) && num > offslab_limit)
break;
+ /* Found something acceptable - save it away */
cachep->num = num;
+ cachep->gfporder = gfporder;
left_over = remainder;
/*
* Large number of objects is good, but very large slabs are
* currently bad for the gfp()s.
*/
- if (cachep->gfporder >= slab_break_gfp_order)
+ if (gfporder >= slab_break_gfp_order)
break;
- if ((left_over * 8) <= (PAGE_SIZE << cachep->gfporder))
- /* Acceptable internal fragmentation */
+ /*
+ * Acceptable internal fragmentation?
+ */
+ if ((left_over * 8) <= (PAGE_SIZE << gfporder))
break;
}
return left_over;