From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751440AbeDVIVg (ORCPT ); Sun, 22 Apr 2018 04:21:36 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:39235 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750916AbeDVIVe (ORCPT ); Sun, 22 Apr 2018 04:21:34 -0400 X-Google-Smtp-Source: AIpwx4+WH26gupAl0RGvjeC7qS8X8H+UkzGW+uRi4daHQOnMo2j5J87Etucr6thuKmAX9QCd+zrRkg== Date: Thu, 19 Apr 2018 12:05:12 +0300 From: "Kirill A. Shutemov" 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 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> User-Agent: NeoMutt/20180323 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: 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