From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f70.google.com (mail-lf0-f70.google.com [209.85.215.70]) by kanga.kvack.org (Postfix) with ESMTP id 025C36B0287 for ; Tue, 25 Oct 2016 18:29:53 -0400 (EDT) Received: by mail-lf0-f70.google.com with SMTP id f134so29789075lfg.6 for ; Tue, 25 Oct 2016 15:29:52 -0700 (PDT) Received: from mail-lf0-x22c.google.com (mail-lf0-x22c.google.com. [2a00:1450:4010:c07::22c]) by mx.google.com with ESMTPS id m127si11713548lfa.186.2016.10.25.15.29.50 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 25 Oct 2016 15:29:51 -0700 (PDT) Received: by mail-lf0-x22c.google.com with SMTP id m193so21567084lfm.4 for ; Tue, 25 Oct 2016 15:29:50 -0700 (PDT) Date: Tue, 25 Oct 2016 15:54:31 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if huge page cache enabled Message-ID: <20161025125431.GA22787@node.shutemov.name> References: <20161025001342.76126-1-kirill.shutemov@linux.intel.com> <20161025001342.76126-19-kirill.shutemov@linux.intel.com> <20161025072122.GA21708@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161025072122.GA21708@infradead.org> Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Hellwig Cc: "Kirill A. Shutemov" , Theodore Ts'o , Andreas Dilger , Jan Kara , Andrew Morton , Alexander Viro , Hugh Dickins , Andrea Arcangeli , Dave Hansen , Vlastimil Babka , Matthew Wilcox , Ross Zwisler , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org On Tue, Oct 25, 2016 at 12:21:22AM -0700, Christoph Hellwig wrote: > On Tue, Oct 25, 2016 at 03:13:17AM +0300, Kirill A. Shutemov wrote: > > We are going to do IO a huge page a time. So we need BIO_MAX_PAGES to be > > at least HPAGE_PMD_NR. For x86-64, it's 512 pages. > > NAK. The maximum bio size should not depend on an obscure vm config, > please send a standalone patch increasing the size to the block list, > with a much long explanation. Also you can't simply increase the size > of the largers pool, we'll probably need more pools instead, or maybe > even implement a similar chaining scheme as we do for struct > scatterlist. The size of required pool depends on architecture: different architectures has different (huge page size)/(base page size). Would it be okay if I add one more pool with size equal to HPAGE_PMD_NR, if it's bigger than than BIO_MAX_PAGES and huge pages are enabled? -- Kirill A. Shutemov -- 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