From: Matt Mackall <mpm@selenic.com>
To: Linux kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: drivers/char/random.c:write_pool() -- cond_resched needed?
Date: Mon, 3 Dec 2007 12:49:59 -0600 [thread overview]
Message-ID: <20071203184958.GN17536@waste.org> (raw)
In-Reply-To: <20071130215810.d3m43bwobifihfiu@m.safari.iki.fi>
On Fri, Nov 30, 2007 at 11:58:10PM +0200, Sami Farin wrote:
> In write_pool(), isn't cond_resched() needed after call to
> add_entropy_words() because otherwise there can be large latencies
> (think of command "dd if=/dev/zero of=/dev/random bs=100000000" ) ?
Yes, looks like you're right.
Reduce latency for large writes to /dev/[u]random
Signed-off-by: Matt Mackall <mpm@selenic.com>
diff -r c60016ba6237 drivers/char/random.c
--- a/drivers/char/random.c Tue Nov 13 09:09:36 2007 -0800
+++ b/drivers/char/random.c Mon Dec 03 12:48:30 2007 -0600
@@ -1041,6 +1041,7 @@ write_pool(struct entropy_store *r, cons
p += bytes;
add_entropy_words(r, buf, (bytes + 3) / 4);
+ cond_resched();
}
return 0;
--
Mathematics is the supreme nostalgia of our time.
prev parent reply other threads:[~2007-12-03 18:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-30 21:58 drivers/char/random.c:write_pool() -- cond_resched needed? Sami Farin
2007-12-03 18:49 ` Matt Mackall [this message]
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