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 09D2BC5475B for ; Mon, 11 Mar 2024 19:56:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 927E96B011F; Mon, 11 Mar 2024 15:56:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8AFB46B011E; Mon, 11 Mar 2024 15:56:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 729C68D0002; Mon, 11 Mar 2024 15:56:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 5C7786B011D for ; Mon, 11 Mar 2024 15:56:33 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 0440C4076B for ; Mon, 11 Mar 2024 19:56:32 +0000 (UTC) X-FDA: 81885815466.02.9174D66 Received: from mail-oo1-f46.google.com (mail-oo1-f46.google.com [209.85.161.46]) by imf01.hostedemail.com (Postfix) with ESMTP id 3525640005 for ; Mon, 11 Mar 2024 19:56:31 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=soleen-com.20230601.gappssmtp.com header.s=20230601 header.b=olgQsQw5; spf=pass (imf01.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.161.46 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com; dmarc=pass (policy=none) header.from=soleen.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1710186991; 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=xmgJJqXMrdbM+pt+OzFLOUDYx+oBh9Zqe5YEPFFSayY=; b=LGiqxdg72ouCNiWqqBAsBilM7cPuY7cBonlaO74QhbSnaRlpX/g3j+FmYGIX/ooMLNMP9w Z4U7acw0hF1PKUyDxtux4wvr/qY7acW3SMOnZEt/aYDI8E9ZuGg5HsaAHn6idt+RvSBmSG 7zERwJmnoNuKD4vX9UU7KGSjDoLktuY= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1710186991; a=rsa-sha256; cv=none; b=d7a2mS2t+WderaJwzJVem8/lL4iZuW7YZ8c2koMvbqwFrwSLxXa2piAenwPZLAQYmW3DZ/ PzA2wO9dSdnXd0yUYCCQnKAXGveeUI63nDJuWJ7Fa/wgaRdsbgzgy4Gf9CENeuY2vghsos 1X1UmRFH6Q1E2lg1Z1WMGCM6eYqy7AM= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=soleen-com.20230601.gappssmtp.com header.s=20230601 header.b=olgQsQw5; spf=pass (imf01.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.161.46 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com; dmarc=pass (policy=none) header.from=soleen.com Received: by mail-oo1-f46.google.com with SMTP id 006d021491bc7-5a207059927so529312eaf.0 for ; Mon, 11 Mar 2024 12:56:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen-com.20230601.gappssmtp.com; s=20230601; t=1710186990; x=1710791790; 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=xmgJJqXMrdbM+pt+OzFLOUDYx+oBh9Zqe5YEPFFSayY=; b=olgQsQw5JAqVOdvN/l/jYY64yX060JmX6F4lp0KDli2m6W+eVzeXwX4mAQNnpEWwPw vBNU60r0MgDKGdGxhvv+wpMbBIrt6pWzNK/n2xlqtjbvQc14tThHZGSLzglo00Mo5Ayj 8TUNe0iPxmTVPeKWsBfZ8BxXWl3FfwDu6K3isIFSFOlg/eMwAtvu8McVql+R9dZ6O2tG RsFLoAk7nQ9xFQ0DUABmcTruwn7Q+inLXh8+tBgG8PZCuXWgJZIEAQMzx4+r/S5ueBft Hr6wrhXfXdoOpEFnWaKoQCKoNuK/BlRRro6kwQezMp7aiArIua0wWTJ95fe2Qe3Jb+Wn p+Rw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710186990; x=1710791790; 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=xmgJJqXMrdbM+pt+OzFLOUDYx+oBh9Zqe5YEPFFSayY=; b=Qc2UfeQCQwz1SLTpRv1n5DPgWivUIShttxgzsvPEBDc5SNWDKgaHZ+ipbF3FuDRhwb Htz5njRybr8T04L93BHv4CfZFRZCTcsjzdnPxXQ2zb7NPS4C38NPJOLBtrT7UoNVVQyG 4c7HDddnAELfp3YJUainc6D8v1p+qJ5wnMAlpK6Fl8eUx+2rdKQHHH5rwk6MOKrEeO/K uaokzH1Kb/8+T4nMNE1dCSe0v7o72Nc4GCauxdW7sFJ6+PLkWC1W5dJZQUM8aruIWNRR 82Ctud4SoP0WxQKF+V0E1ZL+V8ozgePCE1XsMPbbvgimr+If1X75ekXSCOcBg5o+ylgB fewA== X-Forwarded-Encrypted: i=1; AJvYcCXu4tgxtjGHsjYXQLZ2QWiSdTX/7xfKJPC98esrzTflILp4sgM+DQXH6R+AN9RFlBmtS1FVWnlArnVjQeaqiaT32Ms= X-Gm-Message-State: AOJu0Yy4TQSp+J/isftjcUmjtKj19HHc16z84RvHKxD0Ow+sDI0mUe34 uWqa5zntMEffxM3SSTEjHMPVjD1fW1X6ia2B1uFfjfJKHuNSmBjRP42p49o8vbq0LqsJsGDFpxv nKmhX5BBfeGcpwzd/xnGJho5dXSP+D8XqhxKq9JgFW8tVyPn6 X-Google-Smtp-Source: AGHT+IHjdxiMoOTXgmWwHh/swBSwcy+2TOMCnw5OaLYqo+ev86zJ92hBDhWjZOUT7N2vQygfOUpljF32Ly5gE+32DWk= X-Received: by 2002:a05:6358:2909:b0:17b:ed9a:3b00 with SMTP id y9-20020a056358290900b0017bed9a3b00mr9019502rwb.14.1710186990234; Mon, 11 Mar 2024 12:56:30 -0700 (PDT) MIME-Version: 1.0 References: <20240311164638.2015063-1-pasha.tatashin@soleen.com> <20240311164638.2015063-11-pasha.tatashin@soleen.com> <4f77c04b-5fe3-4618-aaaf-7bcc6058591e@infradead.org> In-Reply-To: <4f77c04b-5fe3-4618-aaaf-7bcc6058591e@infradead.org> From: Pasha Tatashin Date: Mon, 11 Mar 2024 15:55:53 -0400 Message-ID: Subject: Re: [RFC 10/14] fork: Dynamic Kernel Stacks To: Randy Dunlap Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, x86@kernel.org, bp@alien8.de, brauner@kernel.org, bristot@redhat.com, bsegall@google.com, dave.hansen@linux.intel.com, dianders@chromium.org, dietmar.eggemann@arm.com, eric.devolder@oracle.com, hca@linux.ibm.com, hch@infradead.org, hpa@zytor.com, jacob.jun.pan@linux.intel.com, jgg@ziepe.ca, jpoimboe@kernel.org, jroedel@suse.de, juri.lelli@redhat.com, kent.overstreet@linux.dev, kinseyho@google.com, kirill.shutemov@linux.intel.com, lstoakes@gmail.com, luto@kernel.org, mgorman@suse.de, mic@digikod.net, michael.christie@oracle.com, mingo@redhat.com, mjguzik@gmail.com, mst@redhat.com, npiggin@gmail.com, peterz@infradead.org, pmladek@suse.com, rick.p.edgecombe@intel.com, rostedt@goodmis.org, surenb@google.com, tglx@linutronix.de, urezki@gmail.com, vincent.guittot@linaro.org, vschneid@redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: zfp5mco1np1endudhttqwf7hfccxda71 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 3525640005 X-Rspam-User: X-HE-Tag: 1710186991-398166 X-HE-Meta: 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 kWJqVskU 0NR9Ha/+cqhQbP4NjBL8lUJI5j949mOCdHvd6aD5nT2MA+2j+V3Wjc/IBXJSoeFNQ7flMkHbaDt76O/FzK2DG00AbKGT4tRCCDxfQuAWLn9KXH8rWGNJupbTwTjmNH8aRFj9fmh7vEsnFV7x6MFbjA13dlORBkrRmOL6PHA6xyQqyFinGE8VvPJMvBXSz0QfJZ9Ge4mE9GE/ot3HAWFZB6kJx98dpC5TVWB+1u3CAMzlLuVlkO5k+nEm8m4wp/b+qPoS4EORXgVKkdWqyzIi5qDSKCp1bfC3hvHHB9bxTtV7teOjqvXxlQqjQ9W8tUpu2K67Ov31+wQqUT7K0LxYM/gjZvtbJEm/AkZ9GXy0rhIM/lXU51ziCYobv4HS54LDaj3DjprvLz5MgZWjJuABAWSALbA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000007, 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, Mar 11, 2024 at 3:32=E2=80=AFPM Randy Dunlap wrote: > > Hi, > > just typos etc. > > On 3/11/24 09:46, Pasha Tatashin wrote: > > The core implementation of dynamic kernel stacks. > > > > ... > > > > > Signed-off-by: Pasha Tatashin > > --- > > arch/Kconfig | 34 +++++ > > include/linux/sched.h | 2 +- > > include/linux/sched/task_stack.h | 41 +++++- > > kernel/fork.c | 239 +++++++++++++++++++++++++++++++ > > kernel/sched/core.c | 1 + > > 5 files changed, 315 insertions(+), 2 deletions(-) > > > > diff --git a/arch/Kconfig b/arch/Kconfig > > index a5af0edd3eb8..da3df347b069 100644 > > --- a/arch/Kconfig > > +++ b/arch/Kconfig > > @@ -1241,6 +1241,40 @@ config VMAP_STACK > > backing virtual mappings with real shadow memory, and KASAN_VMA= LLOC > > must be enabled. > > > > +config HAVE_ARCH_DYNAMIC_STACK > > + def_bool n > > + help > > + An arch should select this symbol if it can support kernel stac= ks > > + dynamic growth. > > + > > + - Arch must have support for HAVE_ARCH_VMAP_STACK, in order to = handle > > + stack related page faults > > stack-related > > > + > > + - Arch must be able to faults from interrupt context. > > fault > > > + - Arch must allows the kernel to handle stack faults gracefully= , even > > allow > > > + during interrupt handling. > > + > > + - Exceptions such as no pages available should be handled the s= ame > > handled in th= e same > > > + in the consitent and predictable way. I.e. the exception shou= ld be > > consistent > > > + handled the same as when stack overflow occurs when guard pag= es are > > + touched with extra information about the allocation error. > > + > > +config DYNAMIC_STACK > > + default y > > + bool "Dynamically grow kernel stacks" > > + depends on THREAD_INFO_IN_TASK > > + depends on HAVE_ARCH_DYNAMIC_STACK > > + depends on VMAP_STACK > > + depends on !KASAN > > + depends on !DEBUG_STACK_USAGE > > + depends on !STACK_GROWSUP > > + help > > + Dynamic kernel stacks allow to save memory on machines with a l= ot of > > + threads by starting with small stacks, and grow them only when = needed. > > + On workloads where most of the stack depth do not reach over on= e page > > does > > > + the memory saving can be subsentantial. The feature requires vi= rtually > > substantial. > > > + mapped kernel stacks in order to handle page faults. > > + > > config HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET > > def_bool n > > help > > > > > +/* > > + * This flag is used to pass information from fault handler to refill = about > > + * which pages were allocated, and should be charged to memcg. > > + */ > > +#define DYNAMIC_STACK_PAGE_AQUIRED_FLAG 0x1 > > ACQUIRED > please Thank you Randy, I will address your comments in my next revision. Pasha > > > > -- > #Randy