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 0035BC021B5 for ; Fri, 21 Feb 2025 17:25:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 58313280016; Fri, 21 Feb 2025 12:25:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 53285280014; Fri, 21 Feb 2025 12:25:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3FAA4280016; Fri, 21 Feb 2025 12:25:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 1AE48280014 for ; Fri, 21 Feb 2025 12:25:18 -0500 (EST) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id BC60851BDF for ; Fri, 21 Feb 2025 17:25:17 +0000 (UTC) X-FDA: 83144627874.01.95A895E Received: from mail-ed1-f47.google.com (mail-ed1-f47.google.com [209.85.208.47]) by imf19.hostedemail.com (Postfix) with ESMTP id B55F11A0017 for ; Fri, 21 Feb 2025 17:25:15 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=NiuxMAPL; spf=pass (imf19.hostedemail.com: domain of kaleshsingh@google.com designates 209.85.208.47 as permitted sender) smtp.mailfrom=kaleshsingh@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=1740158715; 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=/ncBsIXZNHpHN0gN+Ld2krKX7WhegguiyI+QveCr+e8=; b=E1zyBm5PCcnt8t7X3WhQUGmFuq1JYJQFqvYW4rztymVkRDjVQTEgbe0DrPZIlksbWxzkDs qUAnvG0hb0FjBSYJ9VRGRFKR0uLOMP6QIREwEFXX9jyw23PZTT2nSdxkFPg8kJfplyQ4Tb ms/jVu3Ikg60KcTWFmFUZQsFOXNPolk= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=NiuxMAPL; spf=pass (imf19.hostedemail.com: domain of kaleshsingh@google.com designates 209.85.208.47 as permitted sender) smtp.mailfrom=kaleshsingh@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1740158715; a=rsa-sha256; cv=none; b=J7oAHCFrfuz7Fqs7AW+4JlNlRAdSIW+ne2rTrtUXGt05VrMiv//MNyiqgST+0OfAS7bCkq aruoy0Slm7EG4NPVcp2jswAvzDFGm0DAVbJ3e3nxgZsd2EPG/9v+OM0USmCpfRd0d6E9gm dBQve7fxtjmzDfJqi2Bu9EFO5IiX2eo= Received: by mail-ed1-f47.google.com with SMTP id 4fb4d7f45d1cf-5dbfc122b82so12351a12.0 for ; Fri, 21 Feb 2025 09:25:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1740158714; x=1740763514; 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=/ncBsIXZNHpHN0gN+Ld2krKX7WhegguiyI+QveCr+e8=; b=NiuxMAPLg1WO+k+XFqVqvIyl3mLXy28jzeIhnivD/1OoWwDO9Qa+Xm2UPB/wfqaxNP nVtxqkpSFirZvgBZ7aY0hV/tScpXNlVh0Jbwdw4VhMTCe4vLoRPkpHXJxbfr41OG3imv iqWRHGFa11LkdjMiKYfemG4N80o4r/VoFdFleb1SkJQeMM6hyzinIsUAW0857bcN6VLY aXt7ysILmjUhhn3qJZOFoJl/MSjcy9XVgpNDAsNQbVzdLy6i1TIRnvpxYo0Uqe7ezz0h bjumJepTt29nWSCkeMKO+euS/yFHEskRCL1Ud7NnIwsgC7ic2baUxcjB9k8bSuCK6C4W MNJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740158714; x=1740763514; 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=/ncBsIXZNHpHN0gN+Ld2krKX7WhegguiyI+QveCr+e8=; b=T5pMXOmE6lb8SQ3xA9Ajp1PZRYlDgh5j+/7dWiSiNLqCYuJOg0Eu8IBZcGJPPjKeZc WxQjlKLRu1dXJsZr/Hb0g7eJJvTxa+pK1v7jNSMprR3ci5BX4qZdIz6QC6U5uiM2yvts Gw5Dtf73uFquD4JjaVCfJ97xB/vpLzEBHFL34DZ1cgKbAdLnouSP02YNokLogrQI7+Ff LTikHPxKSSZQzlpdtsYf5z4jKPC7MYjMgSaPnq+hliPFXcdTgBmNEfNC4Eo/6o7BuSQ0 yHNuzpM4rEesQIhZlE7jNrIqoa5/ltFxTqC99KE9Rvr0tA87JWIzvSb1Fag1UMT95Ehn OXFw== X-Forwarded-Encrypted: i=1; AJvYcCUwXYfEA9geVKlOzQc3nAtlBTMvgrngRQ7cjE3O1ZYiZl6MkpaVeRXxslqZaL/kgYdX/TpTgVvCAA==@kvack.org X-Gm-Message-State: AOJu0YwygRe4tgV9OOWczDbaoVWhATG/OqQHxYYFtydeC2K96Jx7tuz7 mno+LtG0l+bPVjP50EoFPv/fyRvbKUNbZw+NM3lc/obKgM3aKKdyYx69iXCvjfmDR92Mvst6w2N OvCxuMFFLVvo05FOgQmRAX81rydz/VMtPR6NX X-Gm-Gg: ASbGncuqfFJBB/9ZhKN8RFbpzGKwMS+IkekvmcoqxSEiJ/37KsPnBI9u8vLXxkgLrHY IFYgbCq5fM0ExnBLqfLIyhE+M8iqgBRhZIM6iZUDfYIRf0a6MDtosknTOYKsRXF1ZxAOkosTME5 cOPXx3NqOZqWuUSr7AokjzLreIo59OwYCRpp0F9Ivb X-Google-Smtp-Source: AGHT+IF/mE/upBZOdr7pG47eeKvsSM7BgM6wQXtyL0HhiPJHpy7IiE39CO8Vv/dnFrDxUC6lHMyPi9HwaDMwaO4ANKM= X-Received: by 2002:a50:d657:0:b0:5e0:788e:296c with SMTP id 4fb4d7f45d1cf-5e0b6dedcc7mr116523a12.4.1740158713841; Fri, 21 Feb 2025 09:25:13 -0800 (PST) MIME-Version: 1.0 References: <4aa97b5c-3ddc-442b-8ec9-cc43ebe9e599@redhat.com> <387f3516-99f2-41e9-967e-4b051a8d21b8@redhat.com> <72e044ba-64af-49c0-8b87-ead508654fb7@lucifer.local> <4f5a9c19-9bdd-47eb-bb14-205e3dcced90@redhat.com> <1e959451-2534-44b7-bf62-bc75305048fe@lucifer.local> <31a007c0-884f-495d-ba27-08e3e0dd767d@lucifer.local> <87bae232-b01d-4962-bbe1-3677b71ff752@lucifer.local> In-Reply-To: <87bae232-b01d-4962-bbe1-3677b71ff752@lucifer.local> From: Kalesh Singh Date: Fri, 21 Feb 2025 09:24:59 -0800 X-Gm-Features: AWEUYZnlx1AFsGScoTaTL8obzT8Lj2nGvmv_mtWZZvKaCSW5_GYIYY42YitT7zo Message-ID: Subject: Re: [PATCH 0/4] mm: permit guard regions for file-backed/shmem mappings To: Lorenzo Stoakes Cc: Suren Baghdasaryan , David Hildenbrand , Andrew Morton , "Liam R . Howlett" , Matthew Wilcox , Vlastimil Babka , "Paul E . McKenney" , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shuah Khan , linux-kselftest@vger.kernel.org, linux-api@vger.kernel.org, John Hubbard , Juan Yescas Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: B55F11A0017 X-Stat-Signature: izxtfmhhxip66kte16qqg4or61eokjr8 X-HE-Tag: 1740158715-21476 X-HE-Meta: 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 P65e+QP8 2Zrt35qXL8TPHYutLHzRR5IwqYmfyhKWGg38KdfNvPlNwf9dbHHcwo/06riq9f2aO1FYX/UtaNB22c9C3XAupsjJCHl6Sozvrvzqb32oeUotiIiRR6IXKjvQU5nR2FSYXxdY5i8OdVU5wj9mXyv7sedt0+je4K9maWgSwrhaXC02KrpIXSmIueH+aHjvzF1lD6Xly/sU0B+DrWNwnvQzxdmIJoo3BOhduzHFczJv2t8PSz+qjIsV/mTW8wA== X-Bogosity: Unsure, tests=bogofilter, spamicity=0.454853, 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 Fri, Feb 21, 2025 at 3:04=E2=80=AFAM Lorenzo Stoakes wrote: > > On Thu, Feb 20, 2025 at 10:08:36AM -0800, Kalesh Singh wrote: > > On Thu, Feb 20, 2025 at 8:22=E2=80=AFAM Suren Baghdasaryan wrote: > > > > > > On Thu, Feb 20, 2025 at 5:18=E2=80=AFAM Lorenzo Stoakes > > > wrote: > > > > > > > > On Thu, Feb 20, 2025 at 01:44:20PM +0100, David Hildenbrand wrote: > > > > > On 20.02.25 11:15, Lorenzo Stoakes wrote: > > > > > > On Thu, Feb 20, 2025 at 11:03:02AM +0100, David Hildenbrand wro= te: > > > > > > > > > Your conclusion is 'did not participate with upstream'; I= don't agree with > > > > > > > > > that. But maybe you and Kalesh have a history on that tha= t let's you react > > > > > > > > > on his questions IMHO more emotionally than it should hav= e been. > > > > > > > > > > > > > > > > This is wholly unfair, I have been very reasonable in respo= nse to this > > > > > > > > thread. I have offered to find solutions, I have tried to u= nderstand the > > > > > > > > problem in spite of having gone to great lengths to try to = discuss the > > > > > > > > limitations of the proposed approach in every venue I possi= bly could. > > > > > > > > > > > > > > > > I go out of my way to deal professionally and objectively w= ith what is > > > > > > > > presented. Nothing here is emotional. So I'd ask that you p= lease abstain > > > > > > > > from making commentary like this which has no basis. > > > > > > > > > > > > > > I appreciate everything you write below. But this request is = just > > > > > > > impossible. I will keep raising my opinion and misunderstandi= ngs will > > > > > > > happen. > > > > > > > > > > > > Well I wouldn't ask you not to express your opinion David, you = know I respect > > > > > > and like you, and by all means push back hard or call out what = you think is bad > > > > > > behaviour :) > > > > > > > > > > > > I just meant to say, in my view, that there was no basis, but I= appreciate > > > > > > miscommunications happen. > > > > > > > So apologies if I came off as being difficult or rude, it act= ually > > > > > wasn't > > > > > > intended. And to re-emphasise - I have zero personal issue with= anybody in this > > > > > > thread whatsoever! > > > > > > > > > > It sounded to me like you were trying to defend your work (again,= IMHO too > > > > > emotionally, and I might have completely misinterpreted that) and= slowly > > > > > switching to "friendly fire" (towards me). Apologies from my side= if I > > > > > completely misunderstood/misinterpreted that. > > > > > > > > Right this was not at all my intent, sorry if it seemed that way. I= may well > > > > have communicated terribly, so apologies on my side too. > > > > Hi everyone, > > > > Thank you for all the discussion. > > > > I don't find any personal issues with the communication in this > > thread, but I appreciate David being the object voice of reason. > > > > I understand it can be frustrating since you have made many efforts to > > communicate these tradeoffs. Unfortunately these issues were not known > > for the file-backed ELF guard regions for my particular use case. > > > > > > > > Sorry for being late to the party. Was sick for a couple of days. > > > Lorenzo is right, there was a breakdown in communication at Google an= d > > > he has all the rights to be upset. The issue with obfuscators should > > > have been communicated once it was discovered. I was in regular > > > discussions with Lorenzo but wasn't directly involved with this > > > particular project and wasn't aware or did not realize that the > > > obfuscator issue renders guards unusable for this usecase. My > > > apologies, I should have asked more questions about it. I suspect > > > Lorenzo would have implemented this anyway... > > > > > > > Suren's use case is different from mine and this design fits perfectly > > for anon guard regions from the allocator. :) > > > > So I think in conclusion, these aren't VMAs and shouldn't be treated > > as such; we will advertise them from pagemap for those who need to > > know. > > > > Thanks Kalesh, glad there were no issues here and we have found > constructive common ground! :) > > It turns out implementing the pagemap side of things is _really_ > straightforward, so I'll be sending a series for that shortly. Hopefully > this provides some basis for whichever use cases need this information, a= s > it is the best and least invasive place for this information at this stag= e. Hi Lorenzo, Reviewed your patches, agreed that is the cleanest way to advertise this information. Thanks, Kalesh > > Cheers, Lorenzo > > > -- Kalesh