From: Joel Fernandes <joel@joelfernandes.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Brendan Gregg <bgregg@netflix.com>,
Christian Hansen <chansen3@cisco.com>,
Daniel Colascione <dancol@google.com>,
Florian Mayer <fmayer@google.com>,
John Dias <joaodias@google.com>,
Joel Fernandes <joelaf@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
kernel-team <kernel-team@android.com>,
Linux API <linux-api@vger.kernel.org>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>, Michal Hocko <mhocko@suse.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Minchan Kim <minchan@kernel.org>,
Namhyung Kim <namhyung@google.com>, Roman Gushchin <guro@fb.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Suren Baghdasaryan <surenb@google.com>,
Todd Kjos <tkjos@google.com>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Vlastimil Babka <vbabka@suse.cz>, Wei Wang <wvw@google.com>
Subject: Re: [PATCH v3 1/2] mm/page_idle: Add per-pid idle page tracking using virtual indexing
Date: Tue, 30 Jul 2019 09:06:36 -0400 [thread overview]
Message-ID: <CAEXW_YQN+htU-LpYQ_jxepVdRhO0byw1pWFrsbU2XsH=8FDKLA@mail.gmail.com> (raw)
In-Reply-To: <20190726152319.134152-1-joel@joelfernandes.org>
On Fri, Jul 26, 2019 at 11:23 AM Joel Fernandes (Google)
<joel@joelfernandes.org> wrote:
>
> The page_idle tracking feature currently requires looking up the pagemap
> for a process followed by interacting with /sys/kernel/mm/page_idle.
> Looking up PFN from pagemap in Android devices is not supported by
> unprivileged process and requires SYS_ADMIN and gives 0 for the PFN.
>
> This patch adds support to directly interact with page_idle tracking at
> the PID level by introducing a /proc/<pid>/page_idle file. It follows
> the exact same semantics as the global /sys/kernel/mm/page_idle, but now
> looking up PFN through pagemap is not needed since the interface uses
> virtual frame numbers, and at the same time also does not require
> SYS_ADMIN.
>
> In Android, we are using this for the heap profiler (heapprofd) which
> profiles and pin points code paths which allocates and leaves memory
> idle for long periods of time. This method solves the security issue
> with userspace learning the PFN, and while at it is also shown to yield
> better results than the pagemap lookup, the theory being that the window
> where the address space can change is reduced by eliminating the
> intermediate pagemap look up stage. In virtual address indexing, the
> process's mmap_sem is held for the duration of the access.
>
> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
>
> ---
> v2->v3:
> Fixed a bug where I was doing a kfree that is not needed due to not
> needing to do GFP_ATOMIC allocations.
>
> v1->v2:
> Mark swap ptes as idle (Minchan)
> Avoid need for GFP_ATOMIC (Andrew)
> Get rid of idle_page_list lock by moving list to stack
I believe all suggestions have been addressed. Do these look good now?
thanks,
- Joel
> Internal review -> v1:
> Fixes from Suren.
> Corrections to change log, docs (Florian, Sandeep)
>
> fs/proc/base.c | 3 +
> fs/proc/internal.h | 1 +
> fs/proc/task_mmu.c | 57 +++++++
> include/linux/page_idle.h | 4 +
> mm/page_idle.c | 340 +++++++++++++++++++++++++++++++++-----
> 5 files changed, 360 insertions(+), 45 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 77eb628ecc7f..a58dd74606e9 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -3021,6 +3021,9 @@ static const struct pid_entry tgid_base_stuff[] = {
> REG("smaps", S_IRUGO, proc_pid_smaps_operations),
> REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
next prev parent reply other threads:[~2019-07-30 13:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-26 15:23 [PATCH v3 1/2] mm/page_idle: Add per-pid idle page tracking using virtual indexing Joel Fernandes (Google)
2019-07-26 15:23 ` [PATCH v3 2/2] doc: Update documentation for page_idle virtual address indexing Joel Fernandes (Google)
2019-07-26 20:17 ` sspatil
2019-07-26 20:26 ` Joel Fernandes
2019-07-31 6:44 ` Mike Rapoport
2019-07-30 13:06 ` Joel Fernandes [this message]
2019-07-31 8:53 ` [PATCH v3 1/2] mm/page_idle: Add per-pid idle page tracking using virtual indexing Minchan Kim
2019-07-31 17:19 ` Joel Fernandes
2019-08-05 7:55 ` Minchan Kim
2019-08-05 13:10 ` Joel Fernandes
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='CAEXW_YQN+htU-LpYQ_jxepVdRhO0byw1pWFrsbU2XsH=8FDKLA@mail.gmail.com' \
--to=joel@joelfernandes.org \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=bgregg@netflix.com \
--cc=chansen3@cisco.com \
--cc=corbet@lwn.net \
--cc=dancol@google.com \
--cc=fmayer@google.com \
--cc=guro@fb.com \
--cc=joaodias@google.com \
--cc=joelaf@google.com \
--cc=keescook@chromium.org \
--cc=kernel-team@android.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=namhyung@google.com \
--cc=rppt@linux.ibm.com \
--cc=sfr@canb.auug.org.au \
--cc=surenb@google.com \
--cc=tkjos@google.com \
--cc=vbabka@suse.cz \
--cc=vdavydov.dev@gmail.com \
--cc=wvw@google.com \
/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).