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[54.240.9.46]) by mx.google.com with ESMTPS id y4si1892751qta.151.2019.03.25.07.15.25 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 25 Mar 2019 07:15:26 -0700 (PDT) Received-SPF: pass (google.com: domain of 01000169b534b9e8-31a2af2c-c396-47f9-8534-4cbd934ef09d-000000@amazonses.com designates 54.240.9.46 as permitted sender) client-ip=54.240.9.46; Authentication-Results: mx.google.com; dkim=pass header.i=@amazonses.com header.s=6gbrjpgwjskckoa6a5zn6fwqkn67xbtw header.b=HrFR8unf; spf=pass (google.com: domain of 01000169b534b9e8-31a2af2c-c396-47f9-8534-4cbd934ef09d-000000@amazonses.com designates 54.240.9.46 as permitted sender) smtp.mailfrom=01000169b534b9e8-31a2af2c-c396-47f9-8534-4cbd934ef09d-000000@amazonses.com DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=6gbrjpgwjskckoa6a5zn6fwqkn67xbtw; d=amazonses.com; t=1553523325; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:MIME-Version:Content-Type:Feedback-ID; bh=QxVsvwno82TD/DL3wXtmz3tio2QUfM6l7WxY911mLLw=; b=HrFR8unfmFN4rnnt+Hqsx6IMNV5j6Ea/Am8KbVWjJx5WXZ9vC8pAxsdFJsEwsMr8 IX6ny3v5i4pWq6vZO83gg1U5J8ocP78jveoB25urbgWFuwz8X1ZrdUpqRv3x8XkjIK/ 3zFEhG+E6hEoqvnb3aAcjzbuqhphsuE+dCz+h7hU= Date: Mon, 25 Mar 2019 14:15:25 +0000 From: Christopher Lameter X-X-Sender: cl@nuc-kabylake To: Matthew Wilcox cc: Waiman Long , Oleg Nesterov , Andrew Morton , Pekka Enberg , David Rientjes , Joonsoo Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org, selinux@vger.kernel.org, Paul Moore , Stephen Smalley , Eric Paris , "Peter Zijlstra (Intel)" Subject: Re: [PATCH 2/4] signal: Make flush_sigqueue() use free_q to release memory In-Reply-To: <20190322195926.GB10344@bombadil.infradead.org> Message-ID: <01000169b534b9e8-31a2af2c-c396-47f9-8534-4cbd934ef09d-000000@email.amazonses.com> References: <20190321214512.11524-1-longman@redhat.com> <20190321214512.11524-3-longman@redhat.com> <20190322015208.GD19508@bombadil.infradead.org> <20190322111642.GA28876@redhat.com> <01000169a686689d-bc18fecd-95e1-4b3e-8cd5-dad1b1c570cc-000000@email.amazonses.com> <93523469-48b0-07c8-54fd-300678af3163@redhat.com> <01000169a6ea5e46-f845b8db-730b-436e-980c-3e4273ad2e34-000000@email.amazonses.com> <20190322195926.GB10344@bombadil.infradead.org> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-SES-Outgoing: 2019.03.25-54.240.9.46 Feedback-ID: 1.us-east-1.fQZZZ0Xtj2+TD7V5apTT/NrT6QKuPgzCT/IC7XYgDKI=:AmazonSES 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: On Fri, 22 Mar 2019, Matthew Wilcox wrote: > On Fri, Mar 22, 2019 at 07:39:31PM +0000, Christopher Lameter wrote: > > On Fri, 22 Mar 2019, Waiman Long wrote: > > > > > > > > > >> I am looking forward to it. > > > > There is also alrady rcu being used in these paths. kfree_rcu() would not > > > > be enough? It is an estalished mechanism that is mature and well > > > > understood. > > > > > > > In this case, the memory objects are from kmem caches, so they can't > > > freed using kfree_rcu(). > > > > Oh they can. kfree() can free memory from any slab cache. > > Only for SLAB and SLUB. SLOB requires that you pass a pointer to the > slab cache; it has no way to look up the slab cache from the object. Well then we could either fix SLOB to conform to the others or add a kmem_cache_free_rcu() variant.