From: Johannes Weiner <hannes@cmpxchg.org>
To: Greg Thelen <gthelen@google.com>
Cc: Minchan Kim <minchan.kim@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Dave Young <hidave.darkstar@gmail.com>,
Andrea Righi <arighi@develer.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
Wu Fengguang <fengguang.wu@intel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [patch 0/4] memcg: variable type fixes
Date: Sun, 7 Nov 2010 23:14:35 +0100 [thread overview]
Message-ID: <20101107215030.007259800@cmpxchg.org> (raw)
In-Reply-To: <AANLkTin9m65JVKRuStZ1-qhU5_1AY-GcbBRC0TodsfYC@mail.gmail.com>
Hi Greg,
it is not the res counter primitives, these are our own counters. We
have to keep signed types for most counters, as the per-cpu counter
folding can race and we end up with negative values.
The fix for the original issue is in patch 1. There are no casts
needed, the range is checked to be sane and then converted to the
unsigned type through assignment.
Patch 2, also a type fix, ensures we catch accounting races properly.
It is unrelated, but also important.
Patch 3 implements the idea that we only have to used signed types for
_some_ of the counters, but not for constant event counters where the
sign-bit would be a waste.
Patch 4 converts our fundamental page statistics counters to native
words as these should be wide enough for the expected values.
Hannes
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next prev parent reply other threads:[~2010-11-07 22:15 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-05 16:08 [PATCH] memcg: use do_div to divide s64 in 32 bit machine Minchan Kim
2010-11-05 16:34 ` Greg Thelen
2010-11-06 1:03 ` hannes
2010-11-06 17:19 ` Greg Thelen
2010-11-06 17:31 ` Minchan Kim
2010-11-07 22:14 ` Johannes Weiner [this message]
2010-11-07 22:14 ` [patch 1/4] memcg: use native word to represent dirtyable pages Johannes Weiner
2010-11-07 22:56 ` Minchan Kim
2010-11-08 22:25 ` Greg Thelen
2010-11-08 22:38 ` Johannes Weiner
2010-11-08 22:43 ` Greg Thelen
2010-11-16 3:37 ` KAMEZAWA Hiroyuki
2010-11-07 22:14 ` [patch 2/4] memcg: catch negative per-cpu sums in dirty info Johannes Weiner
2010-11-07 23:26 ` Minchan Kim
2010-11-08 22:28 ` Greg Thelen
2010-11-16 3:39 ` KAMEZAWA Hiroyuki
2010-11-07 22:14 ` [patch 3/4] memcg: break out event counters from other stats Johannes Weiner
2010-11-07 23:52 ` Minchan Kim
2010-11-08 23:20 ` Greg Thelen
2010-11-16 3:41 ` KAMEZAWA Hiroyuki
2010-11-07 22:14 ` [patch 4/4] memcg: use native word page statistics counters Johannes Weiner
2010-11-08 0:01 ` Minchan Kim
2010-11-08 9:08 ` Johannes Weiner
2010-11-08 22:51 ` Greg Thelen
2010-11-08 0:07 ` Minchan Kim
2010-11-08 9:37 ` memcg writeout throttling, was: " Johannes Weiner
2010-11-08 15:45 ` Wu Fengguang
2010-11-08 19:00 ` Greg Thelen
2010-11-08 23:27 ` Greg Thelen
2010-11-08 23:45 ` Johannes Weiner
2010-11-16 3:44 ` KAMEZAWA Hiroyuki
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