Messages in this thread | | | Date | Thu, 2 Jul 2009 08:33:17 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH 2/2] cfq-iosched: get rid of the need for __GFP_FAIL in cfq_find_alloc_queue() |
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On Thu, Jul 02 2009, Shan Wei wrote: > 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.
Sorry I should have been more clear as well, I did merge it for for-linus. It's just your original wording said if was against Linus' main tree, where it didn't apply (the patch would apply, but it would be wrong :-)
It's in upstream now.
-- Jens Axboe
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