From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93CFAC433DF for ; Thu, 11 Jun 2020 01:42:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5046C20801 for ; Thu, 11 Jun 2020 01:42:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="TL6qTLAY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5046C20801 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E4B9B8D006C; Wed, 10 Jun 2020 21:42:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DFA3C8D004C; Wed, 10 Jun 2020 21:42:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CC1E78D006C; Wed, 10 Jun 2020 21:42:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0133.hostedemail.com [216.40.44.133]) by kanga.kvack.org (Postfix) with ESMTP id A9FDE8D004C for ; Wed, 10 Jun 2020 21:42:36 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 6C0E080245D8 for ; Thu, 11 Jun 2020 01:42:36 +0000 (UTC) X-FDA: 76915231512.20.rain64_0a0c6d326dcf Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 4A292180C07AB for ; Thu, 11 Jun 2020 01:42:36 +0000 (UTC) X-HE-Tag: rain64_0a0c6d326dcf X-Filterd-Recvd-Size: 5014 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Thu, 11 Jun 2020 01:42:35 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2C73F207ED; Thu, 11 Jun 2020 01:42:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591839755; bh=gq1jMBSi1avmXNTz1ZIZKTdtMiKuWtdztxDiSEkmWW0=; h=Date:From:To:Subject:In-Reply-To:From; b=TL6qTLAYqRKLk8PHOEiNWhDlpkxLefe/M/Ecb5KFwj6PAAV+0cV0xcilXN0hlsg+X ldcvxYcX3twXJKOoQd5ybqymc8YPrYXCyRh0R7mQXFLtA+MmhGAhrDepYLPjGFP9Hj NqML7TZsCgf4VZkLNy+mNsdXQjL/eOcnCSi5DxU4= Date: Wed, 10 Jun 2020 18:42:33 -0700 From: Andrew Morton To: akpm@linux-foundation.org, alexander.h.duyck@linux.intel.com, axboe@kernel.dk, bgeffon@google.com, christian.brauner@ubuntu.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, linux-mm@kvack.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, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 22/25] mm/madvise: allow KSM hints for remote API Message-ID: <20200611014233.UbeuqJB9Y%akpm@linux-foundation.org> In-Reply-To: <20200610184053.3fa7368ab80e23bfd44de71f@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 4A292180C07AB X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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: Vlastimil Babka Cc: Christian Brauner 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 @@ -1014,6 +1014,10 @@ 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; _