From: Rich Felker <dalias@aerifal.cx>
To: musl@lists.openwall.com
Subject: Re: build musl with clang
Date: Fri, 24 Aug 2012 13:52:51 -0400 [thread overview]
Message-ID: <20120824175251.GF27715@brightrain.aerifal.cx> (raw)
In-Reply-To: <5037BBED.4050509@gentoo.org>
On Fri, Aug 24, 2012 at 07:37:49PM +0200, Luca Barbato wrote:
> On 8/23/12 7:55 PM, Rich Felker wrote:
> >for (i=0; i<n; i++) if (mem[i]) mem[i] = 0;
> >
> >I am not willing to remove the if, because it serves a valuable
> >purpose: it avoids writing to pages that are already all-zero, which
> >in turn reduces swap pressure/dirty pages.
>
> Are you sure absolutely sure it does have the intended effect?
Yes. And actually the problematic code is not that, but the [-1] index
to inspect whether the chunk was obtained from the heap or via mmap.
In the latter case, no zeroing is needed whatsoever.
Rich
next prev parent reply other threads:[~2012-08-24 17:52 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-23 7:53 agent
2012-08-23 9:23 ` Szabolcs Nagy
2012-08-23 10:25 ` agent
2012-08-23 12:24 ` Rich Felker
2012-08-23 13:11 ` agent
2012-08-23 13:56 ` John Spencer
2012-08-23 14:42 ` Szabolcs Nagy
2012-08-23 15:12 ` agent
2012-08-23 17:55 ` Rich Felker
2012-08-24 5:58 ` agent
2012-08-24 6:06 ` Rich Felker
2012-08-24 10:37 ` agent
2012-08-24 11:01 ` Szabolcs Nagy
2012-08-24 12:22 ` agent
2012-08-24 12:35 ` Rich Felker
2012-08-24 12:39 ` agent
2012-08-24 14:59 ` Szabolcs Nagy
2012-08-24 17:51 ` Rich Felker
2012-08-24 18:55 ` agent
2012-08-24 19:04 ` Szabolcs Nagy
2012-08-25 0:09 ` Rich Felker
2012-08-25 5:57 ` agent
2012-08-25 8:03 ` Szabolcs Nagy
2012-08-29 16:21 ` agent
2012-08-29 16:59 ` Rich Felker
2012-08-29 17:50 ` agent
2012-08-24 17:37 ` Luca Barbato
2012-08-24 17:52 ` Rich Felker [this message]
2012-08-23 12:24 ` John Spencer
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