Messages in this thread | | | Date | Thu, 02 Jul 2009 08:49:51 +0800 | From | Shan Wei <> | Subject | Re: [PATCH 2/2] cfq-iosched: get rid of the need for __GFP_FAIL in cfq_find_alloc_queue() |
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Jens Axboe said: > On Wed, Jul 01 2009, Shan Wei wrote: >> Jens Axboe said: >>> Setup an emergency fallback cfqq that we allocate at IO scheduler init >>> time. If the slab allocation fails in cfq_find_alloc_queue(), we'll just >>> punt IO to that cfqq instead. This ensures that cfq_find_alloc_queue() >>> never fails without having to ensure free memory. >>> >>> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> >>> --- >>> >>> @@ -1740,11 +1745,8 @@ cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc, >>> cfqq = *async_cfqq; >>> } >>> >>> - if (!cfqq) { >>> + if (!cfqq) >>> cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); >>> - if (!cfqq) >>> - return NULL; >>> - } >> I jsut reviewed the code and found that the check of cfqq is also redundant >> after doing cfq_get_queue() in cfq_set_request. >> >> The patch is based on Linus's main tree. > > It's not redundant in Linus' tree, cfq_get_queue() can return NULL for > != __GFP_WAIT. >
Yes. So, the patch is only for "for-linus" branch of your tree, not for Linus's tree.
I noticed the patch is in your tree now, thanks.
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