From: Al Viro <viro@ZenIV.linux.org.uk>
To: Namhyung Kim <namhyung@gmail.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fs/buffer.c: change buffer_busy() to use logical-OR expression
Date: Sat, 23 Oct 2010 18:21:07 +0100 [thread overview]
Message-ID: <20101023172107.GQ19804@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1287853575-14190-1-git-send-email-namhyung@gmail.com>
On Sun, Oct 24, 2010 at 02:06:15AM +0900, Namhyung Kim wrote:
> Convert bitwise-OR operator to logical-OR in favor of short-circuit
> evaluation. The end result would be same.
It'll cost _more_.
Think of it:
v = atomic_read(...)
w = bh->b_state
w &= constant
v |= w
return v
vs.
v = atomic_read()
branch to l if not equal to 0
w = bh->b_state
if w & constant is not 0, branch to l
v = 0
return v
l: v = 1
return v
That short-circuit won't win anything here.
next prev parent reply other threads:[~2010-10-23 17:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-23 17:06 [PATCH] fs/buffer.c: change buffer_busy() to use logical-OR expression Namhyung Kim
2010-10-23 17:21 ` Al Viro [this message]
2010-10-23 17:49 ` Namhyung Kim
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20101023172107.GQ19804@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=namhyung@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.