From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + mm-madvise-allow-ksm-hints-for-remote-api.patch added to -mm tree Date: Mon, 02 Mar 2020 13:16:50 -0800 Message-ID: <20200302211650.NHXDF6iT1%akpm@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:52746 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725911AbgCBVQx (ORCPT ); Mon, 2 Mar 2020 16:16:53 -0500 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: alexander.h.duyck@linux.intel.com, axboe@kernel.dk, bgeffon@google.com, christian@brauner.io, dancol@google.com, hannes@cmpxchg.org, jannh@google.com, joaodias@google.com, joel@joelfernandes.org, ktkhai@virtuozzo.com, linux-man@vger.kernel.org, mhocko@suse.com, minchan@kernel.org, mm-commits@vger.kernel.org, oleksandr@redhat.com, shakeelb@google.com, sj38.park@gmail.com, sjpark@amazon.de, sonnyrao@google.com, sspatil@google.com, surenb@google.com, timmurray@google.com The patch titled Subject: mm/madvise: allow KSM hints for remote API has been added to the -mm tree. Its filename is mm-madvise-allow-ksm-hints-for-remote-api.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-madvise-allow-ksm-hints-for-remote-api.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-madvise-allow-ksm-hints-for-remote-api.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Oleksandr Natalenko Subject: mm/madvise: allow KSM hints for remote API It all began with the fact that KSM works only on memory that is marked by madvise(). And the only way to get around that is to either: * use LD_PRELOAD; or * patch the kernel with something like UKSM or PKSM. (i skip ptrace can of worms here intentionally) To overcome this restriction, lets employ a new remote madvise API. This can be used by some small userspace helper daemon that will do auto-KSM job for us. I think of two major consumers of remote KSM hints: * hosts, that run containers, especially similar ones and especially in a trusted environment, sharing the same runtime like Node.js; * heavy applications, that can be run in multiple instances, not limited to opensource ones like Firefox, but also those that cannot be modified since they are binary-only and, maybe, statically linked. Speaking of statistics, more numbers can be found in the very first submission, that is related to this one [1]. For my current setup with two Firefox instances I get 100 to 200 MiB saved for the second instance depending on the amount of tabs. 1 FF instance with 15 tabs: $ echo "$(cat /sys/kernel/mm/ksm/pages_sharing) * 4 / 1024" | bc 410 2 FF instances, second one has 12 tabs (all the tabs are different): $ echo "$(cat /sys/kernel/mm/ksm/pages_sharing) * 4 / 1024" | bc 592 At the very moment I do not have specific numbers for containerised workload, but those should be comparable in case the containers share similar/same runtime. [1] https://lore.kernel.org/patchwork/patch/1012142/ Link: http://lkml.kernel.org/r/20200302193630.68771-8-minchan@kernel.org Signed-off-by: Oleksandr Natalenko Signed-off-by: Minchan Kim Reviewed-by: SeongJae Park Cc: Alexander Duyck Cc: Brian Geffon Cc: Christian Brauner Cc: Daniel Colascione Cc: Jann Horn Cc: Jens Axboe Cc: Joel Fernandes Cc: Johannes Weiner Cc: John Dias Cc: Kirill Tkhai Cc: Michal Hocko Cc: Sandeep Patil Cc: SeongJae Park Cc: Shakeel Butt Cc: Sonny Rao Cc: Suren Baghdasaryan Cc: Tim Murray Cc: Signed-off-by: Andrew Morton --- mm/madvise.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/mm/madvise.c~mm-madvise-allow-ksm-hints-for-remote-api +++ a/mm/madvise.c @@ -1005,6 +1005,10 @@ process_madvise_behavior_valid(int behav switch (behavior) { case MADV_COLD: case MADV_PAGEOUT: +#ifdef CONFIG_KSM + case MADV_MERGEABLE: + case MADV_UNMERGEABLE: +#endif return true; default: return false; _ Patches currently in -mm which might be from oleksandr@redhat.com are mm-madvise-employ-mmget_still_valid-for-write-lock.patch mm-madvise-allow-ksm-hints-for-remote-api.patch