From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 1003B6B02A1 for ; Wed, 2 Nov 2016 10:37:58 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id a136so4410928pfa.5 for ; Wed, 02 Nov 2016 07:37:58 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id s5si3447731pgj.50.2016.11.02.07.37.57 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Nov 2016 07:37:57 -0700 (PDT) Date: Wed, 2 Nov 2016 07:37:49 -0700 From: Christoph Hellwig Subject: Re: [PATCHv3 15/41] filemap: handle huge pages in do_generic_file_read() Message-ID: <20161102143749.GB4790@infradead.org> References: <20160915115523.29737-1-kirill.shutemov@linux.intel.com> <20160915115523.29737-16-kirill.shutemov@linux.intel.com> <20161013093313.GB26241@quack2.suse.cz> <20161031181035.GA7007@node.shutemov.name> <20161101163940.GA5459@quack2.suse.cz> <20161102083204.GB13949@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161102083204.GB13949@node.shutemov.name> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Jan Kara , "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 Wed, Nov 02, 2016 at 11:32:04AM +0300, Kirill A. Shutemov wrote: > Yes, buffer_head list doesn't scale. That's the main reason (along with 4) > why syscall-based IO sucks. We spend a lot of time looking for desired > block. > > We need to switch to some other data structure for storing buffer_heads. > Is there a reason why we have list there in first place? > Why not just array? > > I will look into it, but this sounds like a separate infrastructure change > project. We're working on it with the iomap code. And yes, it's really something that needs to be done before we can consider the THP patches. Same for the biovec thing were we really need the > PAGE_SIZE bio_vecs first. -- 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