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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id 33si3002525plh.3.2019.05.09.07.07.13 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 09 May 2019 07:07:13 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=itWxOZBR; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=5Vk8Apvrfg+i40tbt0Q7wdfTA+VOo7Dy+oZcL8EYyo0=; b=itWxOZBR+b7m3jbCnb8PzwjZg wQSdRv2D0/EdoNXkVMbisfQldFkLmDvQYVYYsI49oCpXPLe7B0RD0p4bBa6VzSQYCZsN8LG4KF2PC OF+Od2EHvv4VOdCkbtSNTPq/L+Zu263bCLAiy41BzRfSI2iHnBTDrmJSA8Yw+ec3fTVlXwj7TuE7k 33nKdV4Gj7SQrtznKjrW0OWZYhOLDnZ82Pigbhm0E/GDGTKGfZ+QH0LARzjbBawuf8qYGndbx4/sO TreZMlVQENJzpVjTkvNjTVNBNBNrig23LKSHYB7H5zHP99IgA4m7Ci0dXGZd3jQX3btFgjBNpKOIv JBqfAmeUw==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1hOjhZ-00062h-9e; Thu, 09 May 2019 14:07:13 +0000 Date: Thu, 9 May 2019 07:07:13 -0700 From: Matthew Wilcox To: Ira Weiny Cc: linux-mm@kvack.org Subject: Re: [RFC 00/11] Remove 'order' argument from many mm functions Message-ID: <20190509140713.GB23561@bombadil.infradead.org> References: <20190507040609.21746-1-willy@infradead.org> <20190509015809.GB26131@iweiny-DESK2.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190509015809.GB26131@iweiny-DESK2.sc.intel.com> User-Agent: Mutt/1.9.2 (2017-12-15) 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 Wed, May 08, 2019 at 06:58:09PM -0700, Ira Weiny wrote: > On Mon, May 06, 2019 at 09:05:58PM -0700, Matthew Wilcox wrote: > > It's possible to save a few hundred bytes from the kernel text by moving > > the 'order' argument into the GFP flags. I had the idea while I was > > playing with THP pagecache (notably, I didn't want to add an 'order' > > parameter to pagecache_get_page()) ... > > Anyway, this is just a quick POC due to me being on an aeroplane for > > most of today. Maybe we don't want to spend five GFP bits on this. > > Some bits of this could be pulled out and applied even if we don't want > > to go for the main objective. eg rmqueue_pcplist() doesn't use its > > gfp_flags argument. > > Over all I may just be a simpleton WRT this but I'm not sure that the added > complexity justifies the gain. I'm disappointed that you see it as added complexity. I see it as reducing complexity. With this patch, we can simply pass GFP_PMD as a flag to pagecache_get_page(); without it, we have to add a fifth parameter to pagecache_get_page() and change all the callers to pass '0'.