提交 9888e6fa 编写于 作者: L Linus Torvalds

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: NLinus Torvalds <torvalds@osdl.org>
上级 f716d830
......@@ -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;
......
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