From: Minchan Kim <minchan@kernel.org>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team <kernel-team@lge.com>,
Ilya Dryomov <idryomov@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [PATCH 4/5] mm:swap: respect page_cluster for readahead
Date: Tue, 12 Sep 2017 17:22:53 +0900 [thread overview]
Message-ID: <20170912082253.GA2875@bbox> (raw)
In-Reply-To: <87mv60nxwa.fsf@yhuang-dev.intel.com>
On Tue, Sep 12, 2017 at 04:07:01PM +0800, Huang, Ying wrote:
< snip >
> >> > My concern is users have been disabled swap readahead by page-cluster would
> >> > be regressed. Please take care of them.
> >>
> >> How about disable VMA based swap readahead if zram used as swap? Like
> >> we have done for hard disk?
> >
> > It could be with SWP_SYNCHRONOUS_IO flag which indicates super-fast,
> > no seek cost swap devices if this patchset is merged so VM automatically
> > disables readahead. It is in my TODO but it's orthogonal work.
> >
> > The problem I raised is "Why shouldn't we obey user's decision?",
> > not zram sepcific issue.
> >
> > A user has used SSD as swap devices decided to disable swap readahead
> > by some reason(e.g., small memory system). Anyway, it has worked
> > via page-cluster for a several years but with vma-based swap devices,
> > it doesn't work any more.
>
> Can they add one more line to their configuration scripts?
>
> echo 0 > /sys/kernel/mm/swap/vma_ra_max_order
We call it as "regression", don't we?
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WARNING: multiple messages have this Message-ID (diff)
From: Minchan Kim <minchan@kernel.org>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team <kernel-team@lge.com>,
Ilya Dryomov <idryomov@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [PATCH 4/5] mm:swap: respect page_cluster for readahead
Date: Tue, 12 Sep 2017 17:22:53 +0900 [thread overview]
Message-ID: <20170912082253.GA2875@bbox> (raw)
In-Reply-To: <87mv60nxwa.fsf@yhuang-dev.intel.com>
On Tue, Sep 12, 2017 at 04:07:01PM +0800, Huang, Ying wrote:
< snip >
> >> > My concern is users have been disabled swap readahead by page-cluster would
> >> > be regressed. Please take care of them.
> >>
> >> How about disable VMA based swap readahead if zram used as swap? Like
> >> we have done for hard disk?
> >
> > It could be with SWP_SYNCHRONOUS_IO flag which indicates super-fast,
> > no seek cost swap devices if this patchset is merged so VM automatically
> > disables readahead. It is in my TODO but it's orthogonal work.
> >
> > The problem I raised is "Why shouldn't we obey user's decision?",
> > not zram sepcific issue.
> >
> > A user has used SSD as swap devices decided to disable swap readahead
> > by some reason(e.g., small memory system). Anyway, it has worked
> > via page-cluster for a several years but with vma-based swap devices,
> > it doesn't work any more.
>
> Can they add one more line to their configuration scripts?
>
> echo 0 > /sys/kernel/mm/swap/vma_ra_max_order
We call it as "regression", don't we?
next prev parent reply other threads:[~2017-09-12 8:22 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-12 2:37 [PATCH 1/5] zram: set BDI_CAP_STABLE_WRITES once Minchan Kim
2017-09-12 2:37 ` Minchan Kim
2017-09-12 2:37 ` [PATCH 2/5] bdi: introduce BDI_CAP_SYNCHRONOUS_IO Minchan Kim
2017-09-12 2:37 ` Minchan Kim
2017-09-12 2:37 ` [PATCH 3/5] mm:swap: introduce SWP_SYNCHRONOUS_IO Minchan Kim
2017-09-12 2:37 ` Minchan Kim
2017-09-12 4:48 ` Sergey Senozhatsky
2017-09-12 4:48 ` Sergey Senozhatsky
2017-09-12 2:37 ` [PATCH 4/5] mm:swap: respect page_cluster for readahead Minchan Kim
2017-09-12 2:37 ` Minchan Kim
2017-09-12 5:23 ` Huang, Ying
2017-09-12 5:23 ` Huang, Ying
2017-09-12 6:25 ` Minchan Kim
2017-09-12 6:25 ` Minchan Kim
2017-09-12 6:44 ` Huang, Ying
2017-09-12 6:44 ` Huang, Ying
2017-09-12 6:52 ` Minchan Kim
2017-09-12 6:52 ` Minchan Kim
2017-09-12 7:29 ` Huang, Ying
2017-09-12 7:29 ` Huang, Ying
2017-09-12 7:56 ` Minchan Kim
2017-09-12 7:56 ` Minchan Kim
2017-09-12 8:07 ` Huang, Ying
2017-09-12 8:07 ` Huang, Ying
2017-09-12 8:22 ` Minchan Kim [this message]
2017-09-12 8:22 ` Minchan Kim
2017-09-12 8:32 ` Huang, Ying
2017-09-12 8:32 ` Huang, Ying
2017-09-12 23:34 ` Minchan Kim
2017-09-12 23:34 ` Minchan Kim
2017-09-13 0:55 ` Huang, Ying
2017-09-13 0:55 ` Huang, Ying
2017-09-12 2:37 ` [PATCH 5/5] mm:swap: skip swapcache for swapin of synchronous device Minchan Kim
2017-09-12 2:37 ` Minchan Kim
2017-09-12 6:04 ` Sergey Senozhatsky
2017-09-12 6:04 ` Sergey Senozhatsky
2017-09-12 6:31 ` Minchan Kim
2017-09-12 6:31 ` Minchan Kim
2017-09-12 20:22 ` kbuild test robot
2017-09-12 20:22 ` kbuild test robot
2017-09-13 0:16 ` Minchan Kim
2017-09-13 0:16 ` Minchan Kim
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