From: Tejun Heo <t...@kernel.org> cfq_get_queue()'s control flow looks like the following.
async_cfqq = NULL; cfqq = NULL; if (!is_sync) { ... async_cfqq = ...; cfqq = *async_cfqq; } if (!cfqq) cfqq = ...; if (!is_sync && !(*async_cfqq)) ...; The only thing the local variable init, the second if, and the async_cfqq test in the third if achieves is to skip cfqq creation and installation if *async_cfqq was already non-NULL. This is needlessly complicated with different tests examining the same condition. Simplify it to the following. if (!is_sync) { ... async_cfqq = ...; cfqq = *async_cfqq; if (cfqq) goto out; } cfqq = ...; if (!is_sync) ...; out: Signed-off-by: Tejun Heo <t...@kernel.org> Acked-by: Jeff Moyer <jmo...@redhat.com> Cc: Vivek Goyal <vgo...@redhat.com> Cc: Arianna Avanzini <avanzini.aria...@gmail.com> Signed-off-by: Jens Axboe <ax...@fb.com> https://jira.sw.ru/browse/PSBM-41334 (cherry picked from commit 4ebc1c61d6185604c97fd0b0355ab668052044ab) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- block/cfq-iosched.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 987c0f9..a4149c3 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3696,25 +3696,26 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, { const int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio); const int ioprio = IOPRIO_PRIO_DATA(cic->ioprio); - struct cfq_queue **async_cfqq = NULL; - struct cfq_queue *cfqq = NULL; + struct cfq_queue **async_cfqq; + struct cfq_queue *cfqq; if (!is_sync) { async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); cfqq = *async_cfqq; + if (cfqq) + goto out; } - if (!cfqq) - cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio); + cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio); /* * pin the queue now that it's allocated, scheduler exit will prune it */ - if (!is_sync && !(*async_cfqq)) { + if (!is_sync) { cfqq->ref++; *async_cfqq = cfqq; } - +out: cfqq->ref++; return cfqq; } -- 2.4.10 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel