From: Andi Kleen <andi@firstfloor.org>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.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 17:27:10 +0100 [thread overview]
Message-ID: <20110317162710.GH11094@one.firstfloor.org> (raw)
In-Reply-To: <20110317161219.GZ10696@random.random>
> What I can tell is with the default khugepaged scan rate, the
> collapse_huge_page will have an impact much smaller than KSM. It could
> have more impact than KSM if you increase khugepaged load to 100% with
> sysfs (because of the more memory that is covered by khugepaged
> compared to only the shared portion of KSM). Then the window gets much
> bigger, but still minor, if you can't trigger it with the testsuite
> it's even less likely to ever happen in practice.
You mean randomly injecting errors?
That tends to be hard and unreliable -- usually we try to have a
specific tester that is not random.
> Did you try the testsuite with khugepaged at 100% load? I think that's
> good indication if this window has any practical significance.
The measurement is simple: run the workloads and do some dumps
with pagetypes and check if the memory with lots of pages
has a state that can be handled by memory_failure()
AFAIK this hasn't been done so far with THP.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2011-03-17 16:27 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 [this message]
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
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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