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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 443F6CC6B3A for ; Thu, 15 Oct 2026 15:51:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:To:Subject:From :Message-ID:Cc:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=hFKDNwcL5zSeZMvtUNUkHPjiEQ7p4vTm0Vb2gSStkZM=; b=ZRjyeZhu37WofbAfjflq9Xse42 TVqheJFcZboNx8vY70sk/wtdqOqz+2u8Iv1gtvlEoNqsCEtuqmQn2W1tW41uQ5XaTsFLOXjlHadE8 AoqT2OusNXOCT5TrgsqlZqmqKEO3FKx5+rhDuYknB2YHxaCZy6JMKuHt/lChcLbGM0HfK/bvpYiTv 7DMPh1oN2TU0EYK8bDVKz16Xx4APh+9ryoBg1eaOtct6EiUhMdGGZA6axXx/rwus+2WVXypZEG4et AY+pi+/wNojC1QWv5wZk3OLcVYqLhHOIMiZhRks33rwytGTqWeWNL7P4KvFrUkPGYbsw5KQSuKfMm gkUsf28A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xHNjp-00000000cSl-3RyR; Thu, 15 Oct 2026 15:51:25 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xHNjm-00000000cRM-2Dni for kexec@lists.infradead.org; Thu, 15 Oct 2026 15:51:22 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id EF27D4066D; Thu, 15 Oct 2026 15:51:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC7FA1F000C4; Thu, 15 Oct 2026 15:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792079481; bh=hFKDNwcL5zSeZMvtUNUkHPjiEQ7p4vTm0Vb2gSStkZM=; h=From:Subject:Reply-To:To:In-Reply-To:References:Date; b=SDHQrqL2+A0Rw44JdNwg9YmHycRfOlrUFKIuQ5inir22wSPwOkm1IuRLeZS17GGWS ElnjJKHuNO2GA1bdfbXBfUow1g3tD1HCPfc3pQZ3A7Ijokc+rKFc+CnzxPFJwT6BaF FkxZ9ESZem0pvKuza0nH0UkjwR2Pu/tcWYJj6MQiSFTBSfPo40wm3SlyX4oPeUFkQf 038JZL1OTrQwJf+9LD85S41YTvYdBevsl8zz3fuPL7stln9hSJl9Jr89+QE9xn8x6O B56BRNKaCC1dJAl8moPhhDlafrHbANIBISNtyeP0z5s/0CccUkfY5a2QZ0r7Hi4Bkv ygL6ouIofnOpQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v1 3/8] x86/mce/intel: Bound cmci_rediscover() to a single topology peer To: "Pasha Tatashin" , kees@kernel.org, rppt@kernel.org, juri.lelli@redhat.com, nik.borisov@suse.com, tglx@kernel.org, vschneid@redhat.com, kprateek.nayak@amd.com, vincent.guittot@linaro.org, bp@alien8.de, thorsten.blum@linux.dev, tony.luck@intel.com, david@kernel.org, mingo@redhat.com, akpm@linux-foundation.org, seanjc@google.com, ljs@kernel.org, zhangguopeng@kylinos.cn, dietmar.eggemann@arm.com, mhocko@suse.com, vinicius.gomes@intel.com, tj@kernel.org, vbabka@kernel.org, peterz@infradead.org, surenb@google.com, hpa@zytor.com, x86@kernel.org, dmatlack@google.com, tim.c.chen@linux.intel.com, kexec@lists.infradead.org, pratyush@kernel.org, dave.hansen@linux.intel.com, rostedt@goodmis.org, gmonaco@redhat.com, jgross@suse.com, mgorman@suse.de, graf@amazon.com, liam@infradead.org, ridong.chen@linux.dev, longman@redhat.com, bsegall@google.com In-Reply-To: <20261015153331.1872641-4-pasha.tatashin@soleen.com> References: <20261015153331.1872641-1-pasha.tatashin@soleen.com> <20261015153331.1872641-4-pasha.tatashin@soleen.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 15 Oct 2026 15:51:19 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org > When a CPU goes offline, cmci_clear() disables CMCI on any MCA banks > owned by that CPU, and mce_cpu_dead() calls cmci_rediscover(). Currently > cmci_rediscover() invokes on_each_cpu(cmci_rediscover_work_func, NULL, 1), > sending a synchronous broadcast IPI to every online CPU in the system, > all of which contend on the global cmci_discover_lock while reading up > to 32 MSR_IA32_MCx_CTL2 MSRs. >=20 > Any bank disabled by cmci_clear() is either thread-private, core-scoped > (shared between SMT threads of the same physical core), L2-cluster-scoped, > die-scoped, or package-scoped: > 1. Any bank index that is already owned by the target peer in its own > mce_banks_owned bitmap is private to a narrower scope than the shared > level and will be skipped by cmci_skip_bank() on the target anyway. > 2. Core- or cluster-shared MCA banks can only be claimed by an online > SMT sibling or L2 cluster peer. > [ ... ] > Total: 22.50 s -> 20.74 s (-7.8%) > cmci_rediscover() (cpu479 offline): > 7,720.6 us -> 0.6 us (-99.99%) >=20 > Signed-off-by: Pasha Tatashin Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261015153331.1872= 641-1-pasha.tatashin@soleen.com?part=3D3