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 62DF1D6ED19 for ; Thu, 21 Nov 2024 12:40:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DD4BF6B00A7; Thu, 21 Nov 2024 07:40:28 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D84586B00A8; Thu, 21 Nov 2024 07:40:28 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C72EB6B00A9; Thu, 21 Nov 2024 07:40:28 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id AA5F26B00A7 for ; Thu, 21 Nov 2024 07:40:28 -0500 (EST) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 5C8EEC10CF for ; Thu, 21 Nov 2024 12:40:28 +0000 (UTC) X-FDA: 82810058184.27.DAB4EC1 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) by imf24.hostedemail.com (Postfix) with ESMTP id 39A7F180012 for ; Thu, 21 Nov 2024 12:40:18 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=desiato.20200630 header.b=AQZ2dw3G; spf=none (imf24.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.92.199) smtp.mailfrom=peterz@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1732192622; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ikpAnH13gbp0BHe1sYaGxmFI2nIUUInCIR7xIHSqhjw=; b=Ai6+Rn4Q9IVliGDQPRflT5hM4578D2D0i+4dl0IJ/VdEHcnJI6JcnviaOGjY5w3HZ48CK1 SzpSYN9GhqM3vxNTOyWR3NHLdN6asnQp1TVpaRaszFtZQOdpRlUIjP2A19tpuch+x0EZwc sDuWLzOy1qFpzpcYVv0I8Jt1006pOCU= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=desiato.20200630 header.b=AQZ2dw3G; spf=none (imf24.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.92.199) smtp.mailfrom=peterz@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1732192622; a=rsa-sha256; cv=none; b=DdS8UpE6Z9NAkkwJp9lU60TJgaQPI3KKjHm+lgPR3ATQRpKOyl5M+8ANNn6MpZqyC/eRBX 8W5zQl37WRQNaPwneh9RjvgDqWno2kEdsl4gAiUjCGAw0y76FgVisMMua1f9Kk4yD26Dy1 F4lSK9s/e/RUbEqTQa6Eu7yymXQ4gtU= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ikpAnH13gbp0BHe1sYaGxmFI2nIUUInCIR7xIHSqhjw=; b=AQZ2dw3G7cIbip5y5YOVoD0RtD 927AGxDlm/cKkwl8CrIw8V7+iEJgbmopNa0dPo0Zsp4AdtEUj7FQ508lfvuTUhEWDud29AnRJB5vn iar09XeXACJREwkkIsnq9KmIXBafd4P1n0hlrwfjuHR4+akH2DOXJ++kkHlk16vSgjLp49hS5LXqD KMwdWMXDVPDFpTZj0kT1gOlOtYuEkZVfqf/S85vBqsjk2coQuXtvV7aoM+DsXkzB24IcAy0qq6qnT D++kovSxCKKB1EY2C2p9m2vSTrshUuugrr4x7V0UbTyYu9VslMnyzX3OTCjww98AVVQHX2ScvJiyD Yp9aWmuw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tE6Tk-00000000a0U-1YEf; Thu, 21 Nov 2024 12:40:12 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 8FDC730068B; Thu, 21 Nov 2024 13:40:11 +0100 (CET) Date: Thu, 21 Nov 2024 13:40:11 +0100 From: Peter Zijlstra To: Andrii Nakryiko Cc: linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, oleg@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, jolsa@kernel.org, paulmck@kernel.org, willy@infradead.org, surenb@google.com, mjguzik@gmail.com, brauner@kernel.org, jannh@google.com, mhocko@kernel.org, vbabka@suse.cz, shakeel.butt@linux.dev, hannes@cmpxchg.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, david@redhat.com, arnd@arndb.de, richard.weiyang@gmail.com, zhangpeng.00@bytedance.com, linmiaohe@huawei.com, viro@zeniv.linux.org.uk, hca@linux.ibm.com Subject: Re: [PATCH v4 tip/perf/core 1/4] mm: Convert mm_lock_seq to a proper seqcount Message-ID: <20241121124011.GK24774@noisy.programming.kicks-ass.net> References: <20241028010818.2487581-1-andrii@kernel.org> <20241028010818.2487581-2-andrii@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241028010818.2487581-2-andrii@kernel.org> X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 39A7F180012 X-Stat-Signature: jh6ifmtysitkcpgyrueggbg53wtejzhr X-Rspam-User: X-HE-Tag: 1732192818-596695 X-HE-Meta: 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 Ocd2lrkq NlVD70T4YuTOkmCpNTMsPb20h9eWZgSauqA4zTvSjG7yARIM/HFkoek60oUFzuF8JNBK9iw0xvOm0HqUiyeRgiRBtaQN7oQYcPPJW9dOwZSOy5nFfKLZxkVlvTiSrLHY4uDtqnbpmHWZ+JBY/BTyS1kh4bjf4+dTiuHv/DYw4/+DsAfZVU5g43iR0MreEz00VwYpiELSijk9G5mus/p7YKMEOJ856W5aYWrWlwp9+Ti3TmgIsIJybWqNCCBpuQia63XnB6snRTWYexYrTwVVeMUV+Jf6hfJVNncocD/byBnIetDI+ePipFAD9VEUsW7jv9jMo7dGKXJxud21OQ6fG0nmBxw== 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 Sun, Oct 27, 2024 at 06:08:15PM -0700, Andrii Nakryiko wrote: > +/* > + * Drop all currently-held per-VMA locks. > + * This is called from the mmap_lock implementation directly before releasing > + * a write-locked mmap_lock (or downgrading it to read-locked). > + * This should normally NOT be called manually from other places. > + * If you want to call this manually anyway, keep in mind that this will release > + * *all* VMA write locks, including ones from further up the stack. > + */ > +static inline void vma_end_write_all(struct mm_struct *mm) > +{ > + mmap_assert_write_locked(mm); > + /* > + * Nobody can concurrently modify mm->mm_lock_seq due to exclusive > + * mmap_lock being held. > + */ You can write: ASSERT_EXCLUSIVE_WRITER(mm->mm_lock_seq); instead of that comment. Then KCSAN will validate the claim. > + mm_lock_seqcount_end(mm); > +}