Messages in this thread | | | Date | Thu, 18 Jul 2013 20:48:00 +0800 | From | Bob Liu <> | Subject | Re: [PATCH] mm: zbud: fix condition check on allocation size |
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On 07/17/2013 10:30 PM, Heesub Shin wrote: > zbud_alloc() incorrectly verifies the size of allocation limit. It > should deny the allocation request greater than (PAGE_SIZE - > ZHDR_SIZE_ALIGNED - CHUNK_SIZE), not (PAGE_SIZE - ZHDR_SIZE_ALIGNED) > which has no remaining spaces for its buddy. There is no point in > spending the entire zbud page storing only a single page, since we don't > have any benefits. > > Signed-off-by: Heesub Shin <heesub.shin@samsung.com>
Looks good to me, although I'm thinking to make it more aggressive. eg. minus two or three times of CHUNK_SIZE.
> --- > mm/zbud.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/zbud.c b/mm/zbud.c > index 9bb4710..ad1e781 100644 > --- a/mm/zbud.c > +++ b/mm/zbud.c > @@ -257,7 +257,7 @@ int zbud_alloc(struct zbud_pool *pool, int size, gfp_t gfp, > > if (size <= 0 || gfp & __GFP_HIGHMEM) > return -EINVAL; > - if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED) > + if (size > PAGE_SIZE - ZHDR_SIZE_ALIGNED - CHUNK_SIZE) > return -ENOSPC; > chunks = size_to_chunks(size); > spin_lock(&pool->lock); >
-- Regards, -Bob
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