From: Andrew Morton <akpm@linux-foundation.org>
To: Michael Rubin <mrubin@google.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, fengguang.wu@intel.com, jack@suse.cz,
riel@redhat.com, david@fromorbit.com,
kosaki.motohiro@jp.fujitsu.com, npiggin@kernel.dk, hch@lst.de,
axboe@kernel.dk
Subject: Re: [PATCH 5/5] writeback: Reporting dirty thresholds in /proc/vmstat
Date: Mon, 13 Sep 2010 14:24:12 -0700 [thread overview]
Message-ID: <20100913142412.dc0f6950.akpm@linux-foundation.org> (raw)
In-Reply-To: <1284357493-20078-6-git-send-email-mrubin@google.com>
On Sun, 12 Sep 2010 22:58:13 -0700
Michael Rubin <mrubin@google.com> wrote:
> The kernel already exposes the user desired thresholds in /proc/sys/vm
> with dirty_background_ratio and background_ratio. But the kernel may
> alter the number requested without giving the user any indication that
> is the case.
>
> Knowing the actual ratios the kernel is honoring can help app developers
> understand how their buffered IO will be sent to the disk.
>
> $ grep threshold /proc/vmstat
> nr_dirty_threshold 409111
> nr_dirty_background_threshold 818223
>
Yes, I think /proc/vmstat is a decent place to put these. The needed
infrastructural support is minimal and although these numbers are
closely tied to the implementation-of-the-day, people should expect
individual fields in /proc/vmstat to appear and disappear at random as
kernel versions change.
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Michael Rubin <mrubin@google.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, fengguang.wu@intel.com, jack@suse.cz,
riel@redhat.com, david@fromorbit.com,
kosaki.motohiro@jp.fujitsu.com, npiggin@kernel.dk, hch@lst.de,
axboe@kernel.dk
Subject: Re: [PATCH 5/5] writeback: Reporting dirty thresholds in /proc/vmstat
Date: Mon, 13 Sep 2010 14:24:12 -0700 [thread overview]
Message-ID: <20100913142412.dc0f6950.akpm@linux-foundation.org> (raw)
In-Reply-To: <1284357493-20078-6-git-send-email-mrubin@google.com>
On Sun, 12 Sep 2010 22:58:13 -0700
Michael Rubin <mrubin@google.com> wrote:
> The kernel already exposes the user desired thresholds in /proc/sys/vm
> with dirty_background_ratio and background_ratio. But the kernel may
> alter the number requested without giving the user any indication that
> is the case.
>
> Knowing the actual ratios the kernel is honoring can help app developers
> understand how their buffered IO will be sent to the disk.
>
> $ grep threshold /proc/vmstat
> nr_dirty_threshold 409111
> nr_dirty_background_threshold 818223
>
Yes, I think /proc/vmstat is a decent place to put these. The needed
infrastructural support is minimal and although these numbers are
closely tied to the implementation-of-the-day, people should expect
individual fields in /proc/vmstat to appear and disappear at random as
kernel versions change.
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next prev parent reply other threads:[~2010-09-13 21:25 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-13 5:58 [PATCH 0/5] writeback: kernel visibility Michael Rubin
2010-09-13 5:58 ` Michael Rubin
2010-09-13 5:58 ` [PATCH 1/5] mm: exporting account_page_dirty Michael Rubin
2010-09-13 5:58 ` Michael Rubin
2010-09-13 5:58 ` [PATCH 2/5] mm: account_page_writeback added Michael Rubin
2010-09-13 5:58 ` Michael Rubin
2010-09-13 5:58 ` [PATCH 3/5] writeback: nr_dirtied and nr_written in /proc/vmstat Michael Rubin
2010-09-13 5:58 ` Michael Rubin
2010-09-13 21:20 ` Andrew Morton
2010-09-13 21:20 ` Andrew Morton
2010-09-13 22:17 ` Michael Rubin
2010-09-13 22:17 ` Michael Rubin
2010-09-15 5:23 ` Michael Rubin
2010-09-15 5:23 ` Michael Rubin
2010-09-13 5:58 ` [PATCH 4/5] writeback: Adding /sys/devices/system/node/<node>/vmstat Michael Rubin
2010-09-13 5:58 ` Michael Rubin
2010-09-13 5:58 ` [PATCH 5/5] writeback: Reporting dirty thresholds in /proc/vmstat Michael Rubin
2010-09-13 5:58 ` Michael Rubin
2010-09-13 21:24 ` Andrew Morton [this message]
2010-09-13 21:24 ` Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2010-09-12 20:30 [PATCH 0/5] writeback: kernel visibility Michael Rubin
2010-09-12 20:30 ` [PATCH 5/5] writeback: Reporting dirty thresholds in /proc/vmstat Michael Rubin
2010-09-12 20:30 ` Michael Rubin
2010-09-13 3:15 ` Wu Fengguang
2010-09-13 3:15 ` Wu Fengguang
2010-09-13 5:45 ` Michael Rubin
2010-09-13 5:45 ` Michael Rubin
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