From: Michal Hocko <mhocko@kernel.org>
To: Minchan Kim <minchan@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@redhat.com>, Shaohua Li <shli@kernel.org>,
Hugh Dickins <hughd@google.com>,
Fengguang Wu <fengguang.wu@intel.com>,
Tim Chen <tim.c.chen@intel.com>,
Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH] mm, swap: Make VMA based swap readahead configurable
Date: Wed, 27 Sep 2017 10:35:12 +0200 [thread overview]
Message-ID: <20170927083512.dydqlqezh5polggb@dhcp22.suse.cz> (raw)
In-Reply-To: <20170927080432.GA1160@bbox>
On Wed 27-09-17 17:04:32, Minchan Kim wrote:
> On Wed, Sep 27, 2017 at 09:48:35AM +0200, Michal Hocko wrote:
> > On Wed 27-09-17 14:04:01, Minchan Kim wrote:
[...]
> > > The problem is users have disabled swap readahead by echo 0 > /proc/sys/
> > > vm/page-cluster are regressed by this new interface /sys/kernel/mm/swap/
> > > vma_ra_max_order. Because for disabling readahead completely, they should
> > > disable vma_ra_max_order as well as page-cluster from now on.
> > >
> > > So, goal of new config to notice new feature to admins so they can be aware
> > > of new konb vma_ra_max_order as well as page-cluster.
> > > I canont think other better idea to preventing such regression.
> > >
> > > http://lkml.kernel.org/r/%3C20170913014019.GB29422@bbox%3E
> >
> > So, how are you going to configure this when you do not know whether
> > zram will be used? In other words what should e.g. distribution set this
> > to?
>
> I have no idea. Unfortunately, it depends on them. If they want to use
> zram as swap, they should fix the script. Surely, I don't like it.
> Instead, I wanted that page-cluster zeroing disables both virtual/pysical
> swap readahead not to break current userspace. However, Huang doesn't
> liek it.
> If you have better idea, please suggest.
I understand your frustration but config options are not there to bypass
proper design decisions. Why cannot we unconditionally disable all the
read ahead when zram is enabled?
--
Michal Hocko
SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org>
To: Minchan Kim <minchan@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@redhat.com>, Shaohua Li <shli@kernel.org>,
Hugh Dickins <hughd@google.com>,
Fengguang Wu <fengguang.wu@intel.com>,
Tim Chen <tim.c.chen@intel.com>,
Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH] mm, swap: Make VMA based swap readahead configurable
Date: Wed, 27 Sep 2017 10:35:12 +0200 [thread overview]
Message-ID: <20170927083512.dydqlqezh5polggb@dhcp22.suse.cz> (raw)
In-Reply-To: <20170927080432.GA1160@bbox>
On Wed 27-09-17 17:04:32, Minchan Kim wrote:
> On Wed, Sep 27, 2017 at 09:48:35AM +0200, Michal Hocko wrote:
> > On Wed 27-09-17 14:04:01, Minchan Kim wrote:
[...]
> > > The problem is users have disabled swap readahead by echo 0 > /proc/sys/
> > > vm/page-cluster are regressed by this new interface /sys/kernel/mm/swap/
> > > vma_ra_max_order. Because for disabling readahead completely, they should
> > > disable vma_ra_max_order as well as page-cluster from now on.
> > >
> > > So, goal of new config to notice new feature to admins so they can be aware
> > > of new konb vma_ra_max_order as well as page-cluster.
> > > I canont think other better idea to preventing such regression.
> > >
> > > http://lkml.kernel.org/r/%3C20170913014019.GB29422@bbox%3E
> >
> > So, how are you going to configure this when you do not know whether
> > zram will be used? In other words what should e.g. distribution set this
> > to?
>
> I have no idea. Unfortunately, it depends on them. If they want to use
> zram as swap, they should fix the script. Surely, I don't like it.
> Instead, I wanted that page-cluster zeroing disables both virtual/pysical
> swap readahead not to break current userspace. However, Huang doesn't
> liek it.
> If you have better idea, please suggest.
I understand your frustration but config options are not there to bypass
proper design decisions. Why cannot we unconditionally disable all the
read ahead when zram is enabled?
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-09-27 8:35 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-21 1:33 [PATCH] mm, swap: Make VMA based swap readahead configurable Huang, Ying
2017-09-21 1:33 ` Huang, Ying
2017-09-25 5:41 ` Minchan Kim
2017-09-25 5:41 ` Minchan Kim
2017-09-25 5:54 ` Huang, Ying
2017-09-25 5:54 ` Huang, Ying
2017-09-25 6:17 ` Minchan Kim
2017-09-25 6:17 ` Minchan Kim
2017-09-25 6:24 ` Huang, Ying
2017-09-25 6:24 ` Huang, Ying
2017-09-25 6:30 ` Minchan Kim
2017-09-25 6:30 ` Minchan Kim
2017-09-26 13:21 ` Michal Hocko
2017-09-26 13:21 ` Michal Hocko
2017-09-27 1:36 ` Huang, Ying
2017-09-27 1:36 ` Huang, Ying
2017-09-27 5:04 ` Minchan Kim
2017-09-27 5:04 ` Minchan Kim
2017-09-27 7:48 ` Michal Hocko
2017-09-27 7:48 ` Michal Hocko
2017-09-27 8:04 ` Minchan Kim
2017-09-27 8:04 ` Minchan Kim
2017-09-27 8:35 ` Michal Hocko [this message]
2017-09-27 8:35 ` Michal Hocko
2017-09-27 13:15 ` Minchan Kim
2017-09-27 13:15 ` Minchan Kim
2017-09-27 13:22 ` Michal Hocko
2017-09-27 13:22 ` Michal Hocko
2017-09-27 13:41 ` Minchan Kim
2017-09-27 13:41 ` Minchan Kim
2017-09-27 13:50 ` Michal Hocko
2017-09-27 13:50 ` Michal Hocko
2017-09-27 14:10 ` Minchan Kim
2017-09-27 14:10 ` Minchan Kim
2017-09-27 14:17 ` Michal Hocko
2017-09-27 14:17 ` Michal Hocko
2017-09-28 1:02 ` Huang, Ying
2017-09-28 1:02 ` Huang, Ying
2017-10-02 7:23 ` Michal Hocko
2017-10-02 7:23 ` Michal Hocko
2017-10-02 15:45 ` Dave Hansen
2017-10-02 15:45 ` Dave Hansen
2017-10-02 21:49 ` Andrew Morton
2017-10-02 21:49 ` Andrew Morton
2017-10-06 12:28 ` huang ying
2017-10-06 12:28 ` huang ying
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