From: Peter Zijlstra <peterz@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Stephane Eranian <eranian@google.com>,
Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"mingo@elte.hu" <mingo@elte.hu>,
"ak@linux.intel.com" <ak@linux.intel.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
David Ahern <dsahern@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
Hugh Dickins <hughd@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC] perf: mmap2 not covering VM_CLONE regions
Date: Wed, 2 Oct 2013 22:31:07 +0200 [thread overview]
Message-ID: <20131002203107.GY3081@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAGXu5jKK+BJnbzJy0pZxVG2BdgxdJ5vNChMRUAJdKrGaHCOsNg@mail.gmail.com>
On Wed, Oct 02, 2013 at 12:38:54PM -0700, Kees Cook wrote:
> On Wed, Oct 2, 2013 at 12:00 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Wed, Oct 02, 2013 at 11:10:15AM -0700, Kees Cook wrote:
> >> Seems like a simple enough solution. Surely there must be a catch. :)
> >
> > I didn't want to add this to the core mm just for perf..
>
> It seems like it would be pretty inexpensive. It might also be
> valuable in other situations. Not that I can think of any at the
> moment. Additionally, it could likely be hidden by a CONFIG, so that
> if perf isn't built in, there's no change?
You optimist, you think you can build a kernel without perf? ;-)
Its just that I would hate to add more completely global state to the
fork() path. The tasklist_lock might be hard to crack, but at least the
pid-hash could use per bucket locks (it doesn't apparently).
I suppose people don't really care that much about fork() performance;
which is sad. KSM and THP also add their own global locks :-(
next prev parent reply other threads:[~2013-10-02 20:31 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-30 15:44 Stephane Eranian
2013-09-30 16:15 ` Peter Zijlstra
2013-09-30 16:48 ` Stephane Eranian
2013-09-30 16:54 ` Peter Zijlstra
2013-10-01 11:22 ` Stephane Eranian
2013-10-02 11:23 ` Peter Zijlstra
2013-10-02 11:58 ` Peter Zijlstra
2013-10-02 12:39 ` Ingo Molnar
2013-10-02 12:46 ` Peter Zijlstra
2013-10-02 12:59 ` Stephane Eranian
2013-10-02 13:01 ` Peter Zijlstra
2013-10-02 13:13 ` Stephane Eranian
2013-10-02 13:37 ` Peter Zijlstra
2013-10-02 17:14 ` Kees Cook
2013-10-02 17:20 ` Stephane Eranian
2013-10-02 17:29 ` Kees Cook
2013-10-02 17:49 ` Stephane Eranian
2013-10-02 18:10 ` Kees Cook
2013-10-02 19:00 ` Peter Zijlstra
2013-10-02 19:38 ` Kees Cook
2013-10-02 20:31 ` Peter Zijlstra [this message]
2013-10-03 8:55 ` Stephane Eranian
2013-10-03 9:03 ` Peter Zijlstra
2013-10-03 9:13 ` Stephane Eranian
2013-10-03 15:34 ` Kees Cook
2013-10-07 21:04 ` Stephane Eranian
2013-10-08 6:54 ` Peter Zijlstra
2013-10-08 7:15 ` Stephane Eranian
2013-10-08 9:36 ` Peter Zijlstra
2013-10-08 9:42 ` Stephane Eranian
2013-10-08 9:54 ` Peter Zijlstra
2013-10-03 18:32 ` Andi Kleen
2013-10-07 11:16 ` Stephane Eranian
2013-10-07 11:32 ` Peter Zijlstra
2013-10-02 15:22 ` Ingo Molnar
2013-10-08 14:23 ` David Ahern
2013-10-08 19:41 ` Ingo Molnar
2013-10-08 19:54 ` Stephane Eranian
2013-10-08 19:57 ` David Ahern
2013-10-09 9:54 ` Ingo Molnar
2013-10-09 9:59 ` Ingo Molnar
2013-10-09 10:39 ` Peter Zijlstra
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=20131002203107.GY3081@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=acme@redhat.com \
--cc=ak@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=dsahern@gmail.com \
--cc=eranian@google.com \
--cc=hughd@google.com \
--cc=jolsa@redhat.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=mingo@kernel.org \
--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
Powered by JetHome