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[195.135.220.15]) by mx.google.com with ESMTPS id h9si3723347edw.334.2019.04.17.06.31.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 17 Apr 2019 06:31:16 -0700 (PDT) Received-SPF: pass (google.com: domain of vbabka@suse.cz designates 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=pass (google.com: domain of vbabka@suse.cz designates 195.135.220.15 as permitted sender) smtp.mailfrom=vbabka@suse.cz X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 31435B136; Wed, 17 Apr 2019 13:31:16 +0000 (UTC) Subject: Re: [PATCH 2/3] mm: separate memory allocation and actual work in alloc_vmap_area() To: Roman Gushchin Cc: Roman Gushchin , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Matthew Wilcox , Johannes Weiner , Kernel Team References: <20190225203037.1317-1-guro@fb.com> <20190225203037.1317-3-guro@fb.com> <20190301164834.GA3154@tower.DHCP.thefacebook.com> From: Vlastimil Babka Openpgp: preference=signencrypt Autocrypt: addr=vbabka@suse.cz; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190301164834.GA3154@tower.DHCP.thefacebook.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 3/1/19 5:48 PM, Roman Gushchin wrote: > On Fri, Mar 01, 2019 at 03:43:19PM +0100, Vlastimil Babka wrote: >> On 2/25/19 9:30 PM, Roman Gushchin wrote: >>> alloc_vmap_area() is allocating memory for the vmap_area, and >>> performing the actual lookup of the vm area and vmap_area >>> initialization. >>> >>> This prevents us from using a pre-allocated memory for the map_area >>> structure, which can be used in some cases to minimize the number >>> of required memory allocations. >> >> Hmm, but that doesn't happen here or in the later patch, right? The only >> caller of init_vmap_area() is alloc_vmap_area(). What am I missing? > > So initially the patch was a part of a bigger patchset, which > tried to minimize the number of separate allocations during vmalloc(), > e.g. by inlining vm_struct->pages into vm_struct for small areas. > > I temporarily dropped the rest of the patchset for some rework, > but decided to leave this patch, because it looks like a nice refactoring > in any case, and also it has been already reviewed and acked by Matthew > and Johannes. OK then, Acked-by: Vlastimil Babka > Thank you for looking into it! >