From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>, Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>, Minchan Kim <minchan@kernel.org>,
Dave Hansen <dave.hansen@intel.com>,
Andi Kleen <andi@firstfloor.org>, H Peter Anvin <hpa@zytor.com>,
Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/4] mm: Send one IPI per CPU to TLB flush all entries after unmapping pages
Date: Tue, 09 Jun 2015 16:01:46 -0400 [thread overview]
Message-ID: <5577462A.40402@redhat.com> (raw)
In-Reply-To: <1433871118-15207-3-git-send-email-mgorman@suse.de>
On 06/09/2015 01:31 PM, Mel Gorman wrote:
> An IPI is sent to flush remote TLBs when a page is unmapped that was
> potentially accesssed by other CPUs. There are many circumstances where
> this happens but the obvious one is kswapd reclaiming pages belonging to
> a running process as kswapd and the task are likely running on separate CPUs.
> It's still a noticeable improvement with vmstat showing interrupts went
> from roughly 500K per second to 45K per second.
>
> The patch will have no impact on workloads with no memory pressure or
> have relatively few mapped pages. It will have an unpredictable impact
> on the workload running on the CPU being flushed as it'll depend on how
> many TLB entries need to be refilled and how long that takes. Worst case,
> the TLB will be completely cleared of active entries when the target PFNs
> were not resident at all.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
--
All rights reversed
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2015-06-09 20:01 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-09 17:31 [PATCH 0/3] TLB flush multiple pages per IPI v6 Mel Gorman
2015-06-09 17:31 ` [PATCH 1/4] x86, mm: Trace when an IPI is about to be sent Mel Gorman
2015-06-09 17:31 ` [PATCH 2/4] mm: Send one IPI per CPU to TLB flush all entries after unmapping pages Mel Gorman
2015-06-09 20:01 ` Rik van Riel [this message]
2015-06-10 7:47 ` Ingo Molnar
2015-06-10 8:14 ` Mel Gorman
2015-06-10 8:21 ` Ingo Molnar
2015-06-10 8:51 ` Mel Gorman
2015-06-10 8:26 ` Ingo Molnar
2015-06-10 9:58 ` Mel Gorman
2015-06-10 8:33 ` Ingo Molnar
2015-06-10 8:59 ` Mel Gorman
2015-06-11 15:02 ` Ingo Molnar
2015-06-11 15:25 ` Mel Gorman
2015-06-09 17:31 ` [PATCH 3/4] mm: Defer flush of writable TLB entries Mel Gorman
2015-06-09 20:02 ` Rik van Riel
2015-06-10 7:50 ` Ingo Molnar
2015-06-10 8:17 ` Mel Gorman
2015-06-09 17:31 ` [PATCH 4/4] mm: Send one IPI per CPU to TLB flush pages that were recently unmapped Mel Gorman
-- strict thread matches above, loose matches on Subject: below --
2015-07-06 13:39 [PATCH 0/4] TLB flush multiple pages per IPI v7 Mel Gorman
2015-07-06 13:39 ` [PATCH 2/4] mm: Send one IPI per CPU to TLB flush all entries after unmapping pages Mel Gorman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5577462A.40402@redhat.com \
--to=riel@redhat.com \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=andi@firstfloor.org \
--cc=dave.hansen@intel.com \
--cc=hpa@zytor.com \
--cc=hughd@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=minchan@kernel.org \
--cc=mingo@kernel.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).