From: Andi Kleen <andi@firstfloor.org>
To: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: unlisted-recipients:;;linux-fsdevel@vger.kernel.org (no
To-header on input),
linux-kernel@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
Chao Yu <chao2.yu@samsung.com>
Subject: Re: [PATCH] f2fs: add unlikely() macro for compiler more aggressively
Date: Fri, 06 Dec 2013 10:24:31 -0800 [thread overview]
Message-ID: <87siu5vnvk.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <1386310509-5864-1-git-send-email-jaegeuk.kim@samsung.com> (Jaegeuk Kim's message of "Fri, 06 Dec 2013 15:15:09 +0900")
Jaegeuk Kim <jaegeuk.kim@samsung.com> writes:
> struct page *page;
> repeat:
> page = grab_cache_page(mapping, index);
> - if (!page) {
> + if (unlikely(!page)) {
This is completely pointless, gcc already considers any test for NULL
unlikely.
In general i would advise against splattering unlikely all over your
code, the benefits are very minimal and programers often get it wrong.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2013-12-06 18:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-06 6:15 [PATCH] f2fs: add unlikely() macro for compiler more aggressively Jaegeuk Kim
2013-12-06 8:34 ` Chao Yu
2013-12-06 18:24 ` Andi Kleen [this message]
2013-12-10 8:03 ` [PATCH v2] " Jaegeuk Kim
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