From: Andrew Morton <akpm@linux-foundation.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guroan@gmail.com>,
linux-mm@kvack.org, Matthew Wilcox <willy@infradead.org>,
kernel-team@fb.com, linux-kernel@vger.kernel.org,
Roman Gushchin <guro@fb.com>
Subject: Re: [PATCH v2 0/3] vmalloc enhancements
Date: Tue, 12 Feb 2019 12:34:09 -0800 [thread overview]
Message-ID: <20190212123409.7ed5c34d68466dbd8b7013a3@linux-foundation.org> (raw)
In-Reply-To: <20190212184724.GA18339@cmpxchg.org>
On Tue, 12 Feb 2019 13:47:24 -0500 Johannes Weiner <hannes@cmpxchg.org> wrote:
> On Tue, Feb 12, 2019 at 09:56:45AM -0800, Roman Gushchin wrote:
> > The patchset contains few changes to the vmalloc code, which are
> > leading to some performance gains and code simplification.
> >
> > Also, it exports a number of pages, used by vmalloc(),
> > in /proc/meminfo.
> >
> > Patch (1) removes some redundancy on __vunmap().
> > Patch (2) separates memory allocation and data initialization
> > in alloc_vmap_area()
> > Patch (3) adds vmalloc counter to /proc/meminfo.
> >
> > v2->v1:
> > - rebased on top of current mm tree
> > - switch from atomic to percpu vmalloc page counter
>
> I don't understand what prompted this change to percpu counters.
>
> All writers already write vmap_area_lock and vmap_area_list, so it's
> not really saving much. The for_each_possible_cpu() for /proc/meminfo
> on the other hand is troublesome.
percpu_counters would fit here. They have probably-unneeded locking
but I expect that will be acceptable.
And they address the issues with for_each_possible_cpu() avoidance, CPU
hotplug and transient negative values.
next prev parent reply other threads:[~2019-02-12 20:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190212175648.28738-1-guro@fb.com>
2019-02-12 17:56 ` [PATCH v2 1/3] mm: refactor __vunmap() to avoid duplicated call to find_vm_area() Roman Gushchin
2019-02-12 17:56 ` [PATCH v2 2/3] mm: separate memory allocation and actual work in alloc_vmap_area() Roman Gushchin
2019-02-12 17:56 ` [PATCH v2 3/3] mm: show number of vmalloc pages in /proc/meminfo Roman Gushchin
2019-02-12 18:47 ` [PATCH v2 0/3] vmalloc enhancements Johannes Weiner
2019-02-12 20:34 ` Andrew Morton [this message]
2019-02-12 22:36 ` Roman Gushchin
2019-02-13 20:26 ` Matthew Wilcox
2019-02-14 0:38 ` Roman Gushchin
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=20190212123409.7ed5c34d68466dbd8b7013a3@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=guro@fb.com \
--cc=guroan@gmail.com \
--cc=hannes@cmpxchg.org \
--cc=kernel-team@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=willy@infradead.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