From patchwork Sat Sep 26 01:57:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 263436 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=-8.0 required=3.0 tests=BAYES_00,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 91B4EC4727D for ; Sat, 26 Sep 2020 01:57:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53AC321741 for ; Sat, 26 Sep 2020 01:57:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601085475; bh=nNYXXG8CmdNa0dataxSs+WwxzEM65kjutU3uMb9U8ig=; h=Date:From:To:Subject:List-ID:From; b=V6qFJjCp0cW0m/yF2jR+L++A28OaJpkf0EjzvkbxSV5ye7HQ6lzQBk23UNpjl/vOl 0ThNOyjNcI3B3t2lV3WdRfMqKnhKrlM9R1r6zX4i5gc2fUVuadZIZ3z3LlaVVQFwyu Egbc3e5Pvid3GFDoB3se/29yiyZlOc7SBEKswrd0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729884AbgIZB5y (ORCPT ); Fri, 25 Sep 2020 21:57:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:40262 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727495AbgIZB5y (ORCPT ); Fri, 25 Sep 2020 21:57:54 -0400 Received: from localhost.localdomain (c-71-198-47-131.hsd1.ca.comcast.net [71.198.47.131]) (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 A0143207EA; Sat, 26 Sep 2020 01:57:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601085474; bh=nNYXXG8CmdNa0dataxSs+WwxzEM65kjutU3uMb9U8ig=; h=Date:From:To:Subject:From; b=uW1B19QLqbQl6fqD3reNrfOGMZIWsWOY3rbDDYsAs3NLzyVLCuYJpvAu/zAMxR7Ca P8q+aS1QuHSBqHnSxaccxdAXx5A3yuwcDVYVSdHKmOZ8zEl/UU5Fz9e1ugFCBJiBcW tElk/UM+b6+LIEA7BWAHUdyG/ft3eCGJBt1Eq1S4= Date: Fri, 25 Sep 2020 18:57:53 -0700 From: akpm@linux-foundation.org To: alex.shi@linux.alibaba.com, cai@lca.pw, hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, shakeelb@google.com, stable@vger.kernel.org Subject: [merged] ksm-reinstate-memcg-charge-on-copied-pages.patch removed from -mm tree Message-ID: <20200926015753.jM6OK4VA3%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: ksm: reinstate memcg charge on copied pages has been removed from the -mm tree. Its filename was ksm-reinstate-memcg-charge-on-copied-pages.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Hugh Dickins Subject: ksm: reinstate memcg charge on copied pages Patch series "mm: fixes to past from future testing". Here's a set of independent fixes against 5.9-rc2: prompted by testing Alex Shi's "warning on !memcg" and lru_lock series, but I think fit for 5.9 - though maybe only the first for stable. This patch (of 5): In 5.8 some instances of memcg charging in do_swap_page() and unuse_pte() were removed, on the understanding that swap cache is now already charged at those points; but a case was missed, when ksm_might_need_to_copy() has decided it must allocate a substitute page: such pages were never charged. Fix it inside ksm_might_need_to_copy(). This was discovered by Alex Shi's prospective commit "mm/memcg: warning on !memcg after readahead page charged". But there is a another surprise: this also fixes some rarer uncharged PageAnon cases, when KSM is configured in, but has never been activated. ksm_might_need_to_copy()'s anon_vma->root and linear_page_index() check sometimes catches a case which would need to have been copied if KSM were turned on. Or that's my optimistic interpretation (of my own old code), but it leaves some doubt as to whether everything is working as intended there - might it hint at rare anon ptes which rmap cannot find? A question not easily answered: put in the fix for missed memcg charges. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301343270.5954@eggly.anvils Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301358020.5954@eggly.anvils Fixes: 4c6355b25e8b ("mm: memcontrol: charge swapin pages on instantiation") Signed-off-by: Hugh Dickins Reviewed-by: Shakeel Butt Acked-by: Johannes Weiner Cc: Alex Shi Cc: Michal Hocko Cc: Mike Kravetz Cc; Matthew Wilcox Cc: Qian Cai Cc: [5.8] Signed-off-by: Andrew Morton --- mm/ksm.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/mm/ksm.c~ksm-reinstate-memcg-charge-on-copied-pages +++ a/mm/ksm.c @@ -2586,6 +2586,10 @@ struct page *ksm_might_need_to_copy(stru return page; /* let do_swap_page report the error */ new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); + if (new_page && mem_cgroup_charge(new_page, vma->vm_mm, GFP_KERNEL)) { + put_page(new_page); + new_page = NULL; + } if (new_page) { copy_user_highpage(new_page, page, address, vma);