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Groups > linux.kernel > #1160707
| Path | csiph.com!aioe.org!bofh.it!news.nic.it!robomod |
|---|---|
| From | Jeff Moyer <jmoyer@redhat.com> |
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 1/8] cfq-iosched: simplify control flow in cfq_get_queue() |
| Date | Mon, 08 Jun 2015 20:40:02 +0200 |
| Message-ID | <pza7M-76e-15@gated-at.bofh.it> (permalink) |
| References | <pz14t-1Vl-9@gated-at.bofh.it> <pz1e9-2mm-7@gated-at.bofh.it> |
| X-Original-To | Tejun Heo <tj@kernel.org> |
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| X-Pcloadletter | What the f**k does that mean? |
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| X-Original-Cc | axboe@kernel.dk, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, vgoyal@redhat.com, avanzini.arianna@gmail.com |
| X-Original-Date | Mon, 08 Jun 2015 14:36:52 -0400 |
| X-Original-Message-ID | <x49vbeyhwsb.fsf@segfault.boston.devel.redhat.com> |
| X-Original-References | <1433753973-23684-1-git-send-email-tj@kernel.org> <1433753973-23684-2-git-send-email-tj@kernel.org> |
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| Xref | aioe.org linux.kernel:1160707 |
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Tejun Heo <tj@kernel.org> writes:
> 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 <tj@kernel.org>
> Cc: Vivek Goyal <vgoyal@redhat.com>
> Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
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Re: [PATCH 1/8] cfq-iosched: simplify control flow in cfq_get_queue() Jeff Moyer <jmoyer@redhat.com> - 2015-06-08 20:40 +0200
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