Messages in this thread Patch in this message | | | Date | Wed, 01 Jul 2009 17:28:29 +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: > 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.
Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com> --- block/cfq-iosched.c | 4 ---- 1 files changed, 0 insertions(+), 4 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 833ec18..c373237 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2307,10 +2307,6 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) cfqq = cic_to_cfqq(cic, is_sync); if (!cfqq) { cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); - - if (!cfqq) - goto queue_fail; - cic_set_cfqq(cic, cfqq, is_sync); }
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