From: Dan Williams <dan.j.williams@intel.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Kees Cook <keescook@chromium.org>, Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v9 3/3] mm: Maintain randomization of page free lists
Date: Wed, 30 Jan 2019 11:24:45 -0800 [thread overview]
Message-ID: <CAPcyv4iEmPGtK5=7ah_0Fyeu17y26TwifDMRYruZtD07nCxD+A@mail.gmail.com> (raw)
In-Reply-To: <20190130191117.GH18811@dhcp22.suse.cz>
On Wed, Jan 30, 2019 at 11:11 AM Michal Hocko <mhocko@kernel.org> wrote:
>
> On Tue 29-01-19 21:02:26, Dan Williams wrote:
> > When freeing a page with an order >= shuffle_page_order randomly select
> > the front or back of the list for insertion.
> >
> > While the mm tries to defragment physical pages into huge pages this can
> > tend to make the page allocator more predictable over time. Inject the
> > front-back randomness to preserve the initial randomness established by
> > shuffle_free_memory() when the kernel was booted.
> >
> > The overhead of this manipulation is constrained by only being applied
> > for MAX_ORDER sized pages by default.
>
> I have asked in v7 but didn't get any response. Do we really ned per
> free_area random pool? Why a global one is not sufficient?
Ah, yes, sorry, overlooked that feedback. A global one is sufficient.
Will rework.
next prev parent reply other threads:[~2019-01-30 19:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-30 5:02 [PATCH v9 0/3] mm: Randomize free memory Dan Williams
2019-01-30 5:02 ` [PATCH v9 1/3] mm: Shuffle initial free memory to improve memory-side-cache utilization Dan Williams
2019-01-30 6:48 ` Mike Rapoport
2019-01-30 18:30 ` Dan Williams
2019-01-30 19:08 ` Michal Hocko
2019-01-31 1:33 ` Dan Williams
2019-01-31 22:14 ` Andrew Morton
2019-01-31 23:04 ` Dan Williams
2019-01-30 5:02 ` [PATCH v9 2/3] mm: Move buddy list manipulations into helpers Dan Williams
2019-01-30 5:02 ` [PATCH v9 3/3] mm: Maintain randomization of page free lists Dan Williams
2019-01-30 19:11 ` Michal Hocko
2019-01-30 19:24 ` Dan Williams [this message]
2019-01-31 22:14 ` Andrew Morton
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='CAPcyv4iEmPGtK5=7ah_0Fyeu17y26TwifDMRYruZtD07nCxD+A@mail.gmail.com' \
--to=dan.j.williams@intel.com \
--cc=akpm@linux-foundation.org \
--cc=dave.hansen@linux.intel.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.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