From: Mel Gorman <mgorman@techsingularity.net>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Jan Kara <jack@suse.cz>, Mel Gorman <mgorman@suse.de>,
Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Hugh Dickins <hughd@google.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Tim Chen <tim.c.chen@linux.intel.com>, Shaohua Li <shli@fb.com>,
J???r???me Glisse <jglisse@redhat.com>,
Michal Hocko <mhocko@suse.com>,
Andrea Arcangeli <aarcange@redhat.com>,
David Rientjes <rientjes@google.com>,
Rik van Riel <riel@redhat.com>, Dave Jiang <dave.jiang@intel.com>,
Aaron Lu <aaron.lu@intel.com>
Subject: Re: [PATCH -V4 -mm] mm, swap: Fix race between swapoff and some swap operations
Date: Thu, 4 Jan 2018 10:21:14 +0000 [thread overview]
Message-ID: <20180104102114.l45sjluuzdgpcfd7@techsingularity.net> (raw)
In-Reply-To: <87lgheh173.fsf@yhuang-dev.intel.com>
On Thu, Jan 04, 2018 at 09:17:36AM +0800, Huang, Ying wrote:
> > Maybe, but in this particular case, I would prefer to go with something
> > more conventional unless there is strong evidence that it's an improvement
> > (which I doubt in this case given the cost of migration overall and the
> > corner case of migrating a dirty page).
>
> So you like page_lock() more than RCU?
In this instance, yes.
> Is there any problem of RCU?
> The object to be protected isn't clear?
>
It's not clear what object is being protected or how it's protected and
it's not the usual means a mapping is pinned. Furthermore, in the event
a page is being truncated, we really do not want to bother doing any
migration work for compaction purposes as it's a waste.
--
Mel Gorman
SUSE Labs
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WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@techsingularity.net>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Jan Kara <jack@suse.cz>, Mel Gorman <mgorman@suse.de>,
Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Hugh Dickins <hughd@google.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Tim Chen <tim.c.chen@linux.intel.com>, Shaohua Li <shli@fb.com>,
J???r???me Glisse <jglisse@redhat.com>,
Michal Hocko <mhocko@suse.com>,
Andrea Arcangeli <aarcange@redhat.com>,
David Rientjes <rientjes@google.com>,
Rik van Riel <riel@redhat.com>, Dave Jiang <dave.jiang@intel.com>,
Aaron Lu <aaron.lu@intel.com>
Subject: Re: [PATCH -V4 -mm] mm, swap: Fix race between swapoff and some swap operations
Date: Thu, 4 Jan 2018 10:21:14 +0000 [thread overview]
Message-ID: <20180104102114.l45sjluuzdgpcfd7@techsingularity.net> (raw)
In-Reply-To: <87lgheh173.fsf@yhuang-dev.intel.com>
On Thu, Jan 04, 2018 at 09:17:36AM +0800, Huang, Ying wrote:
> > Maybe, but in this particular case, I would prefer to go with something
> > more conventional unless there is strong evidence that it's an improvement
> > (which I doubt in this case given the cost of migration overall and the
> > corner case of migrating a dirty page).
>
> So you like page_lock() more than RCU?
In this instance, yes.
> Is there any problem of RCU?
> The object to be protected isn't clear?
>
It's not clear what object is being protected or how it's protected and
it's not the usual means a mapping is pinned. Furthermore, in the event
a page is being truncated, we really do not want to bother doing any
migration work for compaction purposes as it's a waste.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2018-01-04 10:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-20 1:26 [PATCH -V4 -mm] mm, swap: Fix race between swapoff and some swap operations Huang, Ying
2017-12-20 1:26 ` Huang, Ying
2017-12-21 2:16 ` Minchan Kim
2017-12-21 2:16 ` Minchan Kim
2017-12-21 7:48 ` Huang, Ying
2017-12-21 23:58 ` Minchan Kim
2017-12-21 23:58 ` Minchan Kim
2017-12-22 14:14 ` Huang, Ying
2017-12-22 14:14 ` Huang, Ying
2017-12-22 16:14 ` Paul E. McKenney
2017-12-22 16:14 ` Paul E. McKenney
2017-12-25 1:28 ` Huang, Ying
2017-12-25 1:28 ` Huang, Ying
2017-12-23 1:36 ` Minchan Kim
2017-12-23 1:36 ` Minchan Kim
2017-12-26 5:33 ` Huang, Ying
2017-12-26 5:33 ` Huang, Ying
2018-01-02 10:21 ` Mel Gorman
2018-01-02 10:21 ` Mel Gorman
2018-01-02 11:29 ` Jan Kara
2018-01-02 11:29 ` Jan Kara
2018-01-02 13:29 ` Mel Gorman
2018-01-02 13:29 ` Mel Gorman
2018-01-03 0:42 ` Huang, Ying
2018-01-03 0:42 ` Huang, Ying
2018-01-03 9:54 ` Mel Gorman
2018-01-03 9:54 ` Mel Gorman
2018-01-04 1:17 ` Huang, Ying
2018-01-04 1:17 ` Huang, Ying
2018-01-04 10:21 ` Mel Gorman [this message]
2018-01-04 10:21 ` Mel Gorman
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