From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Lameter Subject: Re: [PATCH 1/6] mm: make mm->pinned_vm an atomic64 counter Date: Mon, 21 Jan 2019 21:51:47 +0000 Message-ID: <010001687265e644-49af6f45-e29b-41a7-9cd4-50ff8d64b9f9-000000@email.amazonses.com> References: <20190121174220.10583-1-dave@stgolabs.net> <20190121174220.10583-2-dave@stgolabs.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: <20190121174220.10583-2-dave@stgolabs.net> Sender: linux-kernel-owner@vger.kernel.org To: Davidlohr Bueso Cc: akpm@linux-foundation.org, dledford@redhat.com, jgg@mellanox.com, jack@suse.de, ira.weiny@intel.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Davidlohr Bueso List-Id: linux-rdma@vger.kernel.org On Mon, 21 Jan 2019, Davidlohr Bueso wrote > Taking a sleeping lock to _only_ increment a variable is quite the > overkill, and pretty much all users do this. Furthermore, some drivers > (ie: infiniband and scif) that need pinned semantics can go to quite > some trouble to actually delay via workqueue (un)accounting for pinned > pages when not possible to acquire it. 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[54.240.9.92]) by mx.google.com with ESMTPS id z12si875305qtq.2.2019.01.21.13.51.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 21 Jan 2019 13:51:47 -0800 (PST) Received-SPF: pass (google.com: domain of 010001687265e644-49af6f45-e29b-41a7-9cd4-50ff8d64b9f9-000000@amazonses.com designates 54.240.9.92 as permitted sender) client-ip=54.240.9.92; Authentication-Results: mx.google.com; dkim=pass header.i=@amazonses.com header.s=ug7nbtf4gccmlpwj322ax3p6ow6yfsug header.b=hOn+7cxx; spf=pass (google.com: domain of 010001687265e644-49af6f45-e29b-41a7-9cd4-50ff8d64b9f9-000000@amazonses.com designates 54.240.9.92 as permitted sender) smtp.mailfrom=010001687265e644-49af6f45-e29b-41a7-9cd4-50ff8d64b9f9-000000@amazonses.com DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=ug7nbtf4gccmlpwj322ax3p6ow6yfsug; d=amazonses.com; t=1548107507; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:MIME-Version:Content-Type:Feedback-ID; bh=ItNSaKDGxoD1aSyvb0fxyYSFutq6GEdD+caS/lRflm8=; b=hOn+7cxxXuEjteiGeR7rdjymEElIZfAkaGPapPeOkKf8NsmyUvGUt9gqwIgp/uql zqPGBTEEyNSwyH+GQbJxkdXhR+I+w1WTzr2+NsCagVOfsoXdxp6uIRHtTBeMXvdfUYJ MxDf0DpzxNX5drf9dZ5lRsapvxqxa3tfhYO4Imhk= Date: Mon, 21 Jan 2019 21:51:47 +0000 From: Christopher Lameter X-X-Sender: cl@nuc-kabylake To: Davidlohr Bueso cc: akpm@linux-foundation.org, dledford@redhat.com, jgg@mellanox.com, jack@suse.de, ira.weiny@intel.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Davidlohr Bueso Subject: Re: [PATCH 1/6] mm: make mm->pinned_vm an atomic64 counter In-Reply-To: <20190121174220.10583-2-dave@stgolabs.net> Message-ID: <010001687265e644-49af6f45-e29b-41a7-9cd4-50ff8d64b9f9-000000@email.amazonses.com> References: <20190121174220.10583-1-dave@stgolabs.net> <20190121174220.10583-2-dave@stgolabs.net> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-SES-Outgoing: 2019.01.21-54.240.9.92 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: Message-ID: <20190121215147.F-GZPMUJhFX3p30C0XlCyOUeBuDwxOuFeWgH6EXWess@z> On Mon, 21 Jan 2019, Davidlohr Bueso wrote > Taking a sleeping lock to _only_ increment a variable is quite the > overkill, and pretty much all users do this. Furthermore, some drivers > (ie: infiniband and scif) that need pinned semantics can go to quite > some trouble to actually delay via workqueue (un)accounting for pinned > pages when not possible to acquire it. Reviewed-by: Christoph Lameter