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[54.240.9.34]) by mx.google.com with ESMTPS id g123si1430429qkd.172.2019.05.15.07.00.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 15 May 2019 07:00:09 -0700 (PDT) Received-SPF: pass (google.com: domain of 0100016abbcb13b1-a1f70846-1d8c-4212-8e74-2b9be8c32ce7-000000@amazonses.com designates 54.240.9.34 as permitted sender) client-ip=54.240.9.34; Authentication-Results: mx.google.com; dkim=pass header.i=@amazonses.com header.s=6gbrjpgwjskckoa6a5zn6fwqkn67xbtw header.b=GPh6v1G7; spf=pass (google.com: domain of 0100016abbcb13b1-a1f70846-1d8c-4212-8e74-2b9be8c32ce7-000000@amazonses.com designates 54.240.9.34 as permitted sender) smtp.mailfrom=0100016abbcb13b1-a1f70846-1d8c-4212-8e74-2b9be8c32ce7-000000@amazonses.com DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=6gbrjpgwjskckoa6a5zn6fwqkn67xbtw; d=amazonses.com; t=1557928809; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:MIME-Version:Content-Type:Feedback-ID; bh=4ieRb2nYTufrIwfIxuW2F44/d/JKF6r4h/5BZmbEcuI=; b=GPh6v1G7tBjvpfFjo9hMZCwciiN03v/sot2b6JO2p5YHO8lXYBnhnIAa773fVXRu NGiplz1lNIFeTYhBR7fj8DXMn08uMJgxeOHgROgOZJOZJdlyx8cjerUOr72NjVKKNYE reEPlVqpmXBv9O4oVqSDSIIrIfo8rpP9+X97ikkw= Date: Wed, 15 May 2019 14:00:09 +0000 From: Christopher Lameter X-X-Sender: cl@nuc-kabylake To: Roman Gushchin cc: Andrew Morton , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, Johannes Weiner , Michal Hocko , Rik van Riel , Vladimir Davydov , cgroups@vger.kernel.org Subject: Re: [PATCH v4 5/7] mm: rework non-root kmem_cache lifecycle management In-Reply-To: <20190514213940.2405198-6-guro@fb.com> Message-ID: <0100016abbcb13b1-a1f70846-1d8c-4212-8e74-2b9be8c32ce7-000000@email.amazonses.com> References: <20190514213940.2405198-1-guro@fb.com> <20190514213940.2405198-6-guro@fb.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-SES-Outgoing: 2019.05.15-54.240.9.34 Feedback-ID: 1.us-east-1.fQZZZ0Xtj2+TD7V5apTT/NrT6QKuPgzCT/IC7XYgDKI=:AmazonSES X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 14 May 2019, Roman Gushchin wrote: > To make this possible we need to introduce a new percpu refcounter > for non-root kmem_caches. The counter is initialized to the percpu > mode, and is switched to atomic mode after deactivation, so we never > shutdown an active cache. The counter is bumped for every charged page > and also for every running allocation. So the kmem_cache can't > be released unless all allocations complete. Increase refcounts during each allocation? Looks to be quite heavy processing.