From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 073CE6B0005 for ; Sun, 22 Apr 2018 04:21:35 -0400 (EDT) Received: by mail-wr0-f197.google.com with SMTP id c56-v6so14246941wrc.5 for ; Sun, 22 Apr 2018 01:21:34 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id s6sor2797121edq.32.2018.04.22.01.21.33 for (Google Transport Security); Sun, 22 Apr 2018 01:21:33 -0700 (PDT) Date: Thu, 19 Apr 2018 12:05:12 +0300 From: "Kirill A. Shutemov" Subject: Re: [RFC PATCH] fs: introduce ST_HUGE flag and set it to tmpfs and hugetlbfs Message-ID: <20180419090512.apnalks6s5z63lqq@node.shutemov.name> References: <1523999293-94152-1-git-send-email-yang.shi@linux.alibaba.com> <20180418102744.GA10397@infradead.org> <73090d4b-6831-805b-8b9d-5dff267428d9@linux.alibaba.com> <20180419082810.GA8624@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180419082810.GA8624@infradead.org> Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Hellwig Cc: Yang Shi , viro@zeniv.linux.org.uk, nyc@holomorphy.com, mike.kravetz@oracle.com, kirill.shutemov@linux.intel.com, hughd@google.com, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Apr 19, 2018 at 01:28:10AM -0700, Christoph Hellwig wrote: > On Wed, Apr 18, 2018 at 11:18:25AM -0700, Yang Shi wrote: > > Yes, thanks for the suggestion. I did think about it before I went with the > > new flag. Not like hugetlb, THP will *not* guarantee huge page is used all > > the time, it may fallback to regular 4K page or may get split. I'm not sure > > how the applications use f_bsize field, it might break existing applications > > and the value might be abused by applications to have counter optimization. > > So, IMHO, a new flag may sound safer. > > But st_blksize isn't the block size, that is why I suggested it. It is > the preferred I/O size, and various file systems can report way > larger values than the block size already. I agree. This looks like a better fit. -- Kirill A. Shutemov