From: Greg KH <greg@kroah.com>
To: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: stable@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Christoph Lameter <clameter@sgi.com>, Mel Gorman <mel@csn.ul.ie>,
Andy Whitcroft <apw@shadowen.org>,
Aruna Ramakrishna <aruna.ramakrishna@oracle.com>,
Khalid Aziz <khalid.aziz@oracle.com>
Subject: Re: [PATCH STABLE 4.4-5.3] mm, vmstat: drop zone->lock in /proc/pagetypeinfo
Date: Thu, 27 May 2021 11:15:25 +0200 [thread overview]
Message-ID: <YK9jLRGmaMKPI25z@kroah.com> (raw)
In-Reply-To: <20210526174613.339990-1-stephen.s.brennan@oracle.com>
On Wed, May 26, 2021 at 10:46:13AM -0700, Stephen Brennan wrote:
> Commit 93b3a674485f6a4b8ffff85d1682d5e8b7c51560 upstream
>
> Commit 93b3a674485f ("mm,vmstat: reduce zone->lock holding time by
> /proc/pagetypeinfo") upstream caps the number of iterations over each
> free_list at 100,000, and also drops the zone->lock in between each
> migrate type. Capping the iteration count alters the file contents in
> some cases, which means this approach may not be suitable for stable
> backports.
>
> However, dropping zone->lock in between migrate types (and, as a result,
> page orders) will not change the /proc/pagetypeinfo file contents. It
> can significantly reduce the length of time spent with IRQs disabled,
> which can prevent missed interrupts or soft lockups which we have
> observed on systems with particularly large memory.
>
> Thus, this commit is a modified version of the upstream one which only
> drops the lock in between migrate types.
Now queued up, thanks.
greg k-h
next prev parent reply other threads:[~2021-05-27 9:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-26 17:46 [PATCH STABLE 4.4-5.3] mm, vmstat: drop zone->lock in /proc/pagetypeinfo Stephen Brennan
2021-05-27 9:15 ` Greg KH [this message]
2021-05-27 9:22 ` Patch "mm, vmstat: drop zone->lock in /proc/pagetypeinfo" has been added to the 4.4-stable tree gregkh
2021-05-27 9:23 ` Patch "mm, vmstat: drop zone->lock in /proc/pagetypeinfo" has been added to the 4.9-stable tree gregkh
2021-05-27 9:23 ` Patch "mm, vmstat: drop zone->lock in /proc/pagetypeinfo" has been added to the 4.14-stable tree gregkh
2021-05-27 9:24 ` Patch "mm, vmstat: drop zone->lock in /proc/pagetypeinfo" has been added to the 4.19-stable tree gregkh
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