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]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCB77D41D41 for ; Tue, 12 Nov 2024 00:49:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2A2126B00A0; Mon, 11 Nov 2024 19:49:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 22C3E6B00AF; Mon, 11 Nov 2024 19:49:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0CC9D6B00D5; Mon, 11 Nov 2024 19:49:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id DE0566B00A0 for ; Mon, 11 Nov 2024 19:49:08 -0500 (EST) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 59CDC1218CF for ; Tue, 12 Nov 2024 00:49:08 +0000 (UTC) X-FDA: 82775606928.08.1364A6C Received: from mail-qt1-f181.google.com (mail-qt1-f181.google.com [209.85.160.181]) by imf14.hostedemail.com (Postfix) with ESMTP id D863E100002 for ; Tue, 12 Nov 2024 00:48:20 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=EgUDWFa3; spf=pass (imf14.hostedemail.com: domain of surenb@google.com designates 209.85.160.181 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=1731372314; 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=I+A95GzH1Ll4uC+5CzjJhSIIK7JoMR9EZ8hAhfkjbps=; b=wSYMJrXlDEfpYaLVOX/NwqAN396a0WN4R1c5Eel2UcZp+ahfiSBfX5RMDZ9D4Sil4qjl3l aaaXnIuG4j8BW5wVUnOygJ3qOkT5Cyo48sQZ1ZDXlCSvNHOMNIbu3Htm/+F8arbMHL8/VC e2iJ+AlJUn8L8C8H1jXDnQKtrQrr7qM= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=EgUDWFa3; spf=pass (imf14.hostedemail.com: domain of surenb@google.com designates 209.85.160.181 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=1731372314; a=rsa-sha256; cv=none; b=KhROhU+tid4l5ZEBfj7ZacirQB9YQ/dp5gXOsdfyFgYgFJQLhstzvSHdKuv56/jqGpY9lH EfaBBhIS+9gl8wwRXGSu6tR+9Th5xVody7Gn0CE7do6J3E7+OpLYdAG4hOXgaG3wQIsy8c CLj6w0e8sDQC41rKCBQqvKsdZarogpA= Received: by mail-qt1-f181.google.com with SMTP id d75a77b69052e-4608dddaa35so131691cf.0 for ; Mon, 11 Nov 2024 16:49:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1731372546; x=1731977346; 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=I+A95GzH1Ll4uC+5CzjJhSIIK7JoMR9EZ8hAhfkjbps=; b=EgUDWFa32NrI0XH3RcYHFRdqznGjj5a4SLl7OZNDp7afpOFb/SiTjaevGw1+gfqnAg df2N0x9sRkxNytBj2E8miYXrL803nAI/tI3JEqBcqGi8miKEFic8inF5qPfDSANY3Sb1 7f/JrvrpnUxLWnlK+cNiAIT9RdPOGyWMJEQCxaizIA2tMUdLEwwTncTf+gvXvkEH+kyP 0pOgBREwnO6yjTgYCaNwQ+cdjb7IYzgVIvCIIKoSlwshatEB3pAwdxg5V443hRR5s4xv 90S49vEmEn+OaYL1k5OxEWROIFD8YLbNof1XESLA+QxmuYkAbNp5h6Bk3S/ZHNvJL109 QHUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731372546; x=1731977346; 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=I+A95GzH1Ll4uC+5CzjJhSIIK7JoMR9EZ8hAhfkjbps=; b=aDjDINKdkaUnGwsvG3AlHpmsUi/KC7Ra1POZYOQy2ZJ0hsqKGjd/SbljxyzsDB7v5t NCeTlUX7JxCbAtkWCg1zsSJex4Ip/D/59xhCswG/l86cvA/ab5Aj9TyNxf8A1Z1vMQ3g KXYf/f4LFy9vgRwJh0ogPqQCsgdTZK0U+/eryAQzwDIDFEyvXWl3jsuSDNy3sFg9rwRv IpevmiJKaFefpoSEYe9YzuzCU1mqT3moK6/5RT0PuxjP3Ey72bFQ3kAaBn4FChD5With JZII+d9tj3W1j6xIyqCGYwZWncsFeoWFofFKH9GSaDwmgLepX87KzJVbWvGNme4vuZA+ uPpQ== X-Forwarded-Encrypted: i=1; AJvYcCUcXmCk8aer9qFuOq7eW7STO1Kzdx5QiRXIGbus7ipLH18C5sIv3eCT4K3IGMpjs2YANpYjJGviVA==@kvack.org X-Gm-Message-State: AOJu0Yw188qdfqe18a5CLIr3I5lmo8HyH/FFQXC9acR+5CgumawTpSMy Nx0N8TH9hW+107rZucyGhszlxRBdpK+zMPFGUQsD9JqPX0XJJj+eEr0HuFOI4DXHE6HPi5FznuP TWIqgu871iyFDeZ/WLkghuM6Bi+44BmwMMgBg X-Gm-Gg: ASbGnctYeNRXnOVzlAyVF7PazR/LjRXO4E4ljVq5qmc6nctYL9QHEu61DZQlZb2o5rS IsBoeQIGADJgVxp2jpaPeA20b8EbwMmc= X-Google-Smtp-Source: AGHT+IGbSeZqbmgkC8WW+TVr8vA7oSBz55D/ZdJ5naePZ94IMQ2mxpvLTWKUC+Y4A8FKmlAv1Y1TD/2+abdDv8gppVQ= X-Received: by 2002:ac8:5891:0:b0:462:9e4:de13 with SMTP id d75a77b69052e-4634289433emr105821cf.9.1731372545473; Mon, 11 Nov 2024 16:49:05 -0800 (PST) MIME-Version: 1.0 References: <20241111205506.3404479-1-surenb@google.com> <20241111221839.w4rqqlvvkm42jdgm@offworld> <20241111161102.e047bce4adfbf38002b7a9cf@linux-foundation.org> In-Reply-To: <20241111161102.e047bce4adfbf38002b7a9cf@linux-foundation.org> From: Suren Baghdasaryan Date: Mon, 11 Nov 2024 16:48:54 -0800 Message-ID: Subject: Re: [PATCH 0/4] move per-vma lock into vm_area_struct To: Andrew Morton Cc: willy@infradead.org, liam.howlett@oracle.com, lorenzo.stoakes@oracle.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mjguzik@gmail.com, oliver.sang@intel.com, mgorman@techsingularity.net, david@redhat.com, peterx@redhat.com, oleg@redhat.com, paulmck@kernel.org, brauner@kernel.org, dhowells@redhat.com, hdanton@sina.com, hughd@google.com, minchan@google.com, jannh@google.com, shakeel.butt@linux.dev, souravpanda@google.com, pasha.tatashin@soleen.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D863E100002 X-Stat-Signature: tqmgkiaw36cw4qzfka6o5bximduq4hwc X-Rspam-User: X-HE-Tag: 1731372500-231849 X-HE-Meta: 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 0U9SIQpe F1APRb4/nci2HJmDwPlXrwjKkaFWfPzxU+JE3D3OSu5f6t1f51WoDsyqJjTLVdTfDdW6smLV+kfA0zjkXL331ldJAe6IH4Ri5NH4gfuyF180KPB/TxHOkcue42+xOIHBGApD25O8IaSIlNJlz4C5PUzIxNg5MJ3nPtONm5wgWOqgOPtMUiDbvV+HPN7CAqfSoq78h/Lwzk7cXTNxifJQwmRvRCHdQr++WNmTgk1an8RqKlI365ZN+Cc5wGGfPTkbxw+2NynqNwQlXMCCHvnk5Bray7N2J/ymYWEXZ5u/mvs2h1fOV2lqz7mnyhzKQuJSNOKqCLNucyYgSq57wdwjGtDc1LJtME4dpSI4fMfEFafKHijJRzzJ6ooWwBjfHhAj8b8qa 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 Mon, Nov 11, 2024 at 4:11=E2=80=AFPM Andrew Morton wrote: > > On Mon, 11 Nov 2024 15:19:22 -0800 Suren Baghdasaryan = wrote: > > > On Mon, Nov 11, 2024 at 2:18=E2=80=AFPM Davidlohr Bueso wrote: > > > > > > On Mon, 11 Nov 2024, Suren Baghdasaryan wrote: > > > > > > >To minimize memory overhead, vm_lock implementation is changed from > > > >using rw_semaphore (40 bytes) to an atomic (8 bytes) and several > > > >vm_area_struct members are moved into the last cacheline, resulting > > > >in a less fragmented structure: > > > > > > I am not a fan of building a custom lock, replacing a standard one. > > > > Understandable. > > If we're going to invent a new lock type, I'm thinking we should do > that - make it a standaline thing, add full lockdep support, etc. Yeah, that will make it easy to experiment and replace it with a different lock type if needed. > > I wonder if we could remove the lock from the vma altogeher and use an > old-fashioned hashed lock. An array of locks indexed by the vma > address. It might work well enough, although sizing the array would be > difficult. Ok, sounds like I'll need to experiment a bit with different lock implementations. I'll post a new version without the last two patches, keeping rw_semaphore for now. Thanks! >