From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f71.google.com (mail-it0-f71.google.com [209.85.214.71]) by kanga.kvack.org (Postfix) with ESMTP id C55936B0003 for ; Thu, 15 Feb 2018 10:49:03 -0500 (EST) Received: by mail-it0-f71.google.com with SMTP id b5so536544itd.6 for ; Thu, 15 Feb 2018 07:49:03 -0800 (PST) Received: from resqmta-ch2-11v.sys.comcast.net (resqmta-ch2-11v.sys.comcast.net. [2001:558:fe21:29:69:252:207:43]) by mx.google.com with ESMTPS id u67si1648385iod.280.2018.02.15.07.49.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 15 Feb 2018 07:49:02 -0800 (PST) Date: Thu, 15 Feb 2018 09:49:00 -0600 (CST) From: Christopher Lameter Subject: Re: [patch 1/2] mm, page_alloc: extend kernelcore and movablecore for percent In-Reply-To: <20180215151129.GB12360@bombadil.infradead.org> Message-ID: References: <20180214095911.GB28460@dhcp22.suse.cz> <20180215144525.GG7275@dhcp22.suse.cz> <20180215151129.GB12360@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: Michal Hocko , David Rientjes , Andrew Morton , Jonathan Corbet , Vlastimil Babka , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org On Thu, 15 Feb 2018, Matthew Wilcox wrote: > What if ... on startup, slab allocated a MAX_ORDER page for itself. > It would then satisfy its own page allocation requests from this giant > page. If we start to run low on memory in the rest of the system, slab > can be induced to return some of it via its shrinker. If slab runs low > on memory, it tries to allocate another MAX_ORDER page for itself. The inducing of releasing memory back is not there but you can run SLUB with MAX_ORDER allocations by passing "slab_min_order=9" or so on bootup. > I think even this should reduce fragmentation. We could enhance the > fragmentation reduction by noticing when somebody else releases a page > that was previously part of a slab MAX_ORDER page and handing that page > back to slab. When slab notices that it has an entire MAX_ORDER page free > (and sufficient other memory on hand that it's unlikely to need it soon), > it can hand that MAX_ORDER page back to the page allocator. SLUB will release MAX_ORDER pages if they are completely free with the above configuration. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org