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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8521DCA101F for ; Wed, 10 Sep 2025 14:56:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E40108E0025; Wed, 10 Sep 2025 10:56:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DEFA48E0022; Wed, 10 Sep 2025 10:56:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CDEC88E0025; Wed, 10 Sep 2025 10:56:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id BA4968E0022 for ; Wed, 10 Sep 2025 10:56:24 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 5BC4013BA02 for ; Wed, 10 Sep 2025 14:56:24 +0000 (UTC) X-FDA: 83873641488.08.30E54AC Received: from mail-qt1-f177.google.com (mail-qt1-f177.google.com [209.85.160.177]) by imf30.hostedemail.com (Postfix) with ESMTP id 806FB80002 for ; Wed, 10 Sep 2025 14:56:22 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=rrYSUMaB; spf=pass (imf30.hostedemail.com: domain of surenb@google.com designates 209.85.160.177 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1757516182; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=A16G7msev3POt8MhMV8+fmCV6RQoltrKiKjwD56M3og=; b=09DDyV51WRXDmpvV+HqJTjFegsR7h7r7h0guUbvkPKWmt9GWTrpLPqZoUXklknM/F2njS7 88M0dFksAAyWkrBSuMQ/u2Z6Ht6eEV2kl42YgjFAmVzbm3ljTGl2kY2DdlZusamxHZjIe0 lB5ZewyGVQLxeF7s16yHJi8St6IEOMU= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=rrYSUMaB; spf=pass (imf30.hostedemail.com: domain of surenb@google.com designates 209.85.160.177 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1757516182; a=rsa-sha256; cv=none; b=FipKNvp65Tn1M5hr0QX37UVeae2mcCCYrt8rBrd20W4+kvIj66wPicjmYeN5BVvxSc2T96 0alfkj8M/aL6vTYuwezvZzXTXNFdZ8KaIMdrCQ6s6MMPKRvo8WrbJuTGIRsbmmMRQs8qhy yTv6UD9tLqxTtBIUkJvW9+yJ/FshZTw= Received: by mail-qt1-f177.google.com with SMTP id d75a77b69052e-4b4bcb9638aso593181cf.0 for ; Wed, 10 Sep 2025 07:56:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1757516181; x=1758120981; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=A16G7msev3POt8MhMV8+fmCV6RQoltrKiKjwD56M3og=; b=rrYSUMaBwkqEuzuEKLb3uSiPRoGZxqYMBzyqaM57yFhVAiV0HK8Zr6dW00/ElOaaj8 gGvJPW/DUBJo2/4LRAfe8Sp61fV9zTI9fhBE0Lt0zoqDKqv08nhTaWp/K6R74COQow0O kZcjZJWK68whwdYdatwiAHOrjDyvZTYvIkM1iLfUlD2D+nDmjYKrD+k9ejKVQh0iyCLO yZW1P10iOFMFDHRhT4Nsry+Y2s5cuWxG+tIKzb+nO812/UpAdqw1KWY6MLGU97MQ4Edi PuIJLFcJa6Ly3poVmH0YNzH7l62H+q2NIC+grBzIZRyKQWSkliEpKNTabLZBMTFvjf4S 8r5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757516181; x=1758120981; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=A16G7msev3POt8MhMV8+fmCV6RQoltrKiKjwD56M3og=; b=Az5QI3xsukeZdGQctNDFYZOJphM/P4b7fnoszveKyD9mhftwqQxrL68DZOoufeCa2X plgHcjIegatleE3rCn+Bb9OMP6wwodyYUDZoyD6OfMfsxp5cOAJwAlHLOfBKoz8itEdK nw6Ul36rHnPVLYs1WoiJiwhdWI0mMLBu5Dg1buUaHBxMraG+ZydwcpfcGe2yHx/Dxcba vYsm+iQxn4jQj2elSOHVT73f9MA7iROHkCZb2PdESsLtn+FPhaVcauGOVY9E8pj5QMH+ OzKPPK62HCUk4LmyklW5OT1jGgKtO7wnfxmS6cQ2p23NRzMBgGnw9V5EgvcIG1uv/nn3 ZXig== X-Forwarded-Encrypted: i=1; AJvYcCXnZhLZt1HsGB3vxSDo7l6ISiAKPDUFDFq/Vityx5B/buaF/1xDMqO+n1yfHGS2DgEc9Jfs+YpxzA==@kvack.org X-Gm-Message-State: AOJu0Yw7y0EJRgLvxJITdmPdoCJm84xaxJ94afM06SEZINIm0yHthF6A BYyWZplP8avyJuwYtIhl+omG+4u35fr5as9KMlkKskDOrDRq0aRiBwW48b5K5i7Pcw3kGXLRVA3 CCsITzDJ4yLCM4ezvSVeqKKQ8NWCFMkBRicesxbsc X-Gm-Gg: ASbGncuDphv66pZFb818doGCuees02V7srTQKxbf97BsQM0ssOB1o6IkDlC8DiQgkcT U6VA4TLF+cMYxRX0M6BTHDDR/NPcuQE4TGp0YpccmayHQ8lPpOmCYR+uJu8PvnoTfr6WlSXgVW6 xEkemQRMK4jaW2FUJr8GDW8X/bHie8hUl+g9ubeLvVYQ2Rzg0EvtWfYq2WxV+3WmLCe8zfAhY+0 Q27oiLbqD0mmBhwV4Lgjq3p0A1dYfV+BJpeLc4AgMIHbBqKnnsBRA== X-Google-Smtp-Source: AGHT+IGaaCo3evsn7RGNzMZzR6JhniZdVW9a85shLUbENP9DBHr6Mi63wI05PWTCudwIISeltuesuE5/JBo1OoWg68g= X-Received: by 2002:a05:622a:199d:b0:4b3:4947:242a with SMTP id d75a77b69052e-4b625236043mr5421861cf.12.1757516180932; Wed, 10 Sep 2025 07:56:20 -0700 (PDT) MIME-Version: 1.0 References: <20250909065349.574894-1-liulei.rjpt@vivo.com> In-Reply-To: From: Suren Baghdasaryan Date: Wed, 10 Sep 2025 07:56:09 -0700 X-Gm-Features: AS18NWDh7ZJPWGaScD2chXrEfeSkcnJTIGCOkVmB8eEUGK_Q5MBQiEFvWnW-pIg Message-ID: Subject: Re: [PATCH v0 0/2] mm: swap: Gather swap entries and batch async release To: Lei Liu Cc: Shakeel Butt , Michal Hocko , David Rientjes , Andrew Morton , Kemeng Shi , Kairui Song , Nhat Pham , Baoquan He , Barry Song , Chris Li , Johannes Weiner , Roman Gushchin , Muchun Song , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Brendan Jackman , Zi Yan , "Peter Zijlstra (Intel)" , Chen Yu , Hao Jia , "Kirill A. Shutemov" , Usama Arif , Oleg Nesterov , Christian Brauner , Mateusz Guzik , Steven Rostedt , Andrii Nakryiko , Al Viro , Fushuai Wang , "open list:MEMORY MANAGEMENT - OOM KILLER" , open list , "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: c4i4635zmujwmm6mricryoro8xxfrjzd X-Rspam-User: X-Rspamd-Queue-Id: 806FB80002 X-Rspamd-Server: rspam04 X-HE-Tag: 1757516182-897132 X-HE-Meta: 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 bIAO6YGm eaQprogYKxP9zNFDxRh+Af1RziYq6dw2+LS3e9PrO582mBi0nKA5v85ff/OehorSCt+Rdc8h1pJt3kuyRxXreWFqdKu3f5qNzcHAHVtMQ1puEsxlw/fmvTGXRzO/pIV0VapYFYW4YbzYQJ3/iPBy3xJlI/Q+x3OWfLUIABK+7qPp8NmX8GyGWa+qi2zMEdf1hfYLC948Nl+XTJaKdAXMxmf3OqxB98ta0VkDu 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: List-Subscribe: List-Unsubscribe: On Wed, Sep 10, 2025 at 7:14=E2=80=AFAM Lei Liu wrot= e: > > > On 2025/9/10 3:48, Suren Baghdasaryan wrote: > > On Tue, Sep 9, 2025 at 12:21=E2=80=AFPM Shakeel Butt wrote: > >> On Tue, Sep 09, 2025 at 02:53:39PM +0800, Lei Liu wrote: > >>> 1. Problem Scenario > >>> On systems with ZRAM and swap enabled, simultaneous process exits cre= ate > >>> contention. The primary bottleneck occurs during swap entry release > >>> operations, causing exiting processes to monopolize CPU resources. Th= is > >>> leads to scheduling delays for high-priority processes. > >>> > >>> 2. Android Use Case > >>> During camera launch, LMKD terminates background processes to free me= mory. > >> How does LMKD trigger the kills? SIGKILL or cgroup.kill? > > SIGKILL > > > >>> Exiting processes compete for CPU cycles, delaying the camera preview > >>> thread and causing visible stuttering - directly impacting user > >>> experience. > >> Since the exit/kill is due to low memory situation, punting the memory > >> freeing to a low priority async mechanism will help in improving user > >> experience. Most probably the application (camera preview here) will g= et > >> into global reclaim and will compete for CPU with the async memory > >> freeing. > >> > >> What we really need is faster memory freeing and we should explore all > >> possible ways. As others suggested fix/improve the bottleneck in the > >> memory freeing path. In addition I think we should explore parallelizi= ng > >> this as well. > >> > >> On Android, I suppose most of the memory is associated with single or > >> small set of processes and parallelizing memory freeing would be > >> challenging. BTW is LMKD using process_mrelease() to release the kille= d > >> process memory? > > Yes, LMKD has a reaper thread which wakes up and calls > > process_mrelease() after the main LMKD thread issued SIGKILL. > > Hi Suren > > our current issue is that after lmkd kills a process,|exit_mm|takes > considerable time. The interface you provided might help quickly free > memory, potentially allowing us to release some memory from processes > before lmkd kills them. This could be a good idea. > > We will take your suggestion into consideration. I wasn't really suggesting anything, just explaining how LMKD works today. > > > Thank you > > > > > >