Messages in this thread | | | Subject | Re: [linux-next-20130422] Bug in SLAB? | From | Tetsuo Handa <> | Date | Fri, 10 May 2013 21:38:47 +0900 |
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Tetsuo Handa wrote: > Can we manage with allocating only 26 elements when MAX_ORDER + PAGE_SHIFT > 26 > (e.g. PAGE_SIZE == 256 * 1024) ? > > Can kmalloc_index()/kmalloc_size()/kmalloc_slab() etc. work correctly when > MAX_ORDER + PAGE_SHIFT > 26 (e.g. PAGE_SIZE == 256 * 1024) ? > Today I compared SLAB/SLUB code. If I understood correctly, the line
if (size <= 64 * 1024 * 1024) return 26;
in kmalloc_index() is redundant (in fact, kmalloc_caches[26] is out of range) and conflicts with what the comment
* The largest kmalloc size supported by the SLAB allocators is * 32 megabyte (2^25) or the maximum allocatable page order if that is * less than 32 MB.
says, and 0 <= kmalloc_index() <= 25 is always true for SLAB and 0 <= kmalloc_index() <= PAGE_SHIFT+1 is always true for SLUB.
Therefore, towards 3.10-rc1,
> > - for (i = 1; i < PAGE_SHIFT + MAX_ORDER; i++) { > > + for (i = 1; i =< KMALLOC_SHIFT_HIGH; i++) { > -+ for (i = 1; i =< KMALLOC_SHIFT_HIGH; i++) { ++ for (i = 1; i <= KMALLOC_SHIFT_HIGH; i++) {
would be the last fix for me. (I don't know why kmalloc_caches[0] is excluded.)
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