From: Andi Kleen <andi@firstfloor.org>
To: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Huang Ying <ying.huang@intel.com>,
Jin Dongming <jin.dongming@np.css.fujitsu.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] Check whether pages are poisoned before copying
Date: Thu, 17 Mar 2011 16:21:50 +0100 [thread overview]
Message-ID: <20110317152150.GF11094@one.firstfloor.org> (raw)
In-Reply-To: <4D81BB87.10803@jp.fujitsu.com>
> At least copy to the last page of the huge page is performed after
> all preceding copies are finished. So I'm not sure it is really
> "a few" or not.
> Still I think making the window smaller than now is worthwhile,
> no matter it is change from 0.1% to 0.01%, or from 0.01% to 0.001%.
Note that hwpoison will never reach 100% coverage. That's impossible.
But to get nearer to 100% it's better to concentrate of the paths
that affect long time windows and significant amounts of memory.
What those are is often non-obvious and needs measurements.
>
> Or did you find the downside of the check here?
The usual problem is how to test it. That tends to be harder
than just writing the code. If it's not tested it's probably
not worth having.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2011-03-17 15:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-17 2:30 [PATCH 0/4] THP: page collapsing vs. poisoning Hidetoshi Seto
2011-03-17 2:31 ` [PATCH 1/4] Lock the new THP when collapsing pages Hidetoshi Seto
2011-03-17 2:32 ` [PATCH 2/4] Free the collapsed pages after the new THP is mapped Hidetoshi Seto
2011-03-17 2:32 ` [PATCH 3/4] Check whether pages are poisoned before copying Hidetoshi Seto
2011-03-17 4:14 ` Andi Kleen
2011-03-17 5:20 ` Hidetoshi Seto
2011-03-17 6:26 ` Andi Kleen
2011-03-17 7:43 ` Hidetoshi Seto
2011-03-17 14:04 ` Andrea Arcangeli
2011-03-17 15:25 ` Andi Kleen
2011-03-17 16:12 ` Andrea Arcangeli
2011-03-17 16:27 ` Andi Kleen
2011-03-17 16:47 ` Andrea Arcangeli
2011-03-17 22:55 ` Andi Kleen
2011-03-23 17:26 ` K.Prasad
2011-03-23 17:32 ` Andi Kleen
2011-03-17 15:21 ` Andi Kleen [this message]
2011-03-18 5:26 ` Jin Dongming
2011-03-17 2:33 ` [PATCH 4/4] Check whether the new THP is poisoned before it is mapped to APL Hidetoshi Seto
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