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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Hugh Dickins <hughd@google.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>,
	Ying Han <yinghan@google.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC 00/15] mm: memory book keeping and lru_lock splitting
Date: Mon, 20 Feb 2012 09:32:17 +0900	[thread overview]
Message-ID: <20120220093217.764e49f3.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <alpine.LSU.2.00.1202172312030.14811@eggly.anvils>

On Fri, 17 Feb 2012 23:14:01 -0800 (PST)
Hugh Dickins <hughd@google.com> wrote:

> On Sat, 18 Feb 2012, Konstantin Khlebnikov wrote:
> > Hugh Dickins wrote:
> > > On Thu, 16 Feb 2012, Hugh Dickins wrote:
> > > > 
> > > > Yours are not the only patches I was testing in that tree, I tried to
> > > > gather several other series which I should be reviewing if I ever have
> > > > time: Kamezawa-san's page cgroup diet 6, Xiao Guangrong's 4 prio_tree
> > > > cleanups, your 3 radix_tree changes, your 6 shmem changes, your 4 memcg
> > > > miscellaneous, and then your 15 books.
> > > > 
> > > > The tree before your final 15 did well under pressure, until I tried to
> > > > rmdir one of the cgroups afterwards: then it crashed nastily, I'll have
> > > > to bisect into that, probably either Kamezawa's or your memcg changes.
> > > 
> > > So far I haven't succeeded in reproducing that at all: it was real,
> > > but obviously harder to get than I assumed - indeed, no good reason
> > > to associate it with any of those patches, might even be in 3.3-rc.
> > > 
> > > It did involve a NULL pointer dereference in mem_cgroup_page_lruvec(),
> > > somewhere below compact_zone() - but repercussions were causing the
> > > stacktrace to scroll offscreen, so I didn't get good details.
> > 
> > There some stupid bugs in my v1 patchset, it shouldn't works at all.
> > I did not expect that someone will try to use it. I sent it just to discuss.
> 
> Yes, but as I said, that bug appeared before I put your patchset (the 15) on.
> 

Hm, NULL pointer dereference in mem_cgroup_page_lruvec() via comaction tend to
mean pc->mem_cgroup was NULL... 

IIUC,

- compaction get pages from LRU list and isolate/migrate them. So, When pages
  on LRU were migrated by compact_zone(), pc->mem_cgroup never be NULL..
- All newly allocated pages for migration will be reset by mem_cgroup_reset_owner().

Hm, something unexpected happens..

Regards,
-Kame
 

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      reply	other threads:[~2012-02-20  0:33 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-15 22:57 Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 01/15] mm: rename struct lruvec into struct book Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 02/15] mm: memory bookkeeping core Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 03/15] mm: add book->pages_count Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 04/15] mm: unify inactive_list_is_low() Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 05/15] mm: add book->reclaim_stat Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 06/15] mm: kill struct mem_cgroup_zone Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 07/15] mm: move page-to-book translation upper Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 08/15] mm: introduce book locking primitives Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 09/15] mm: handle book relocks on lumpy reclaim Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 10/15] mm: handle book relocks in compaction Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 11/15] mm: handle book relock in memory controller Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 12/15] mm: optimize books in update_page_reclaim_stat() Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 13/15] mm: optimize books in pagevec_lru_move_fn() Konstantin Khlebnikov
2012-02-15 22:57 ` [PATCH RFC 14/15] mm: optimize putback for 0-order reclaim Konstantin Khlebnikov
2012-02-15 22:58 ` [PATCH RFC 15/15] mm: split zone->lru_lock Konstantin Khlebnikov
2012-02-16  2:04 ` [PATCH RFC 00/15] mm: memory book keeping and lru_lock splitting KAMEZAWA Hiroyuki
2012-02-16  5:43   ` Konstantin Khlebnikov
2012-02-16  8:24     ` KAMEZAWA Hiroyuki
2012-02-16 11:02       ` Konstantin Khlebnikov
2012-02-16 15:54         ` Konstantin Khlebnikov
2012-02-16 23:54         ` KAMEZAWA Hiroyuki
2012-02-18  9:09           ` Konstantin Khlebnikov
2012-02-16  2:37 ` Hugh Dickins
2012-02-16  4:51   ` Konstantin Khlebnikov
2012-02-16 21:37     ` Hugh Dickins
2012-02-17 19:56       ` Konstantin Khlebnikov
2012-02-18  2:13       ` Hugh Dickins
2012-02-18  6:35         ` Konstantin Khlebnikov
2012-02-18  7:14           ` Hugh Dickins
2012-02-20  0:32             ` KAMEZAWA Hiroyuki [this message]

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