From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from a.ns.miles-group.at ([95.130.255.143] helo=radon.swed.at) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Z1sgA-0000AS-EV for linux-mtd@lists.infradead.org; Mon, 08 Jun 2015 08:45:11 +0000 Message-ID: <557555F6.4030009@nod.at> Date: Mon, 08 Jun 2015 10:44:38 +0200 From: Richard Weinberger MIME-Version: 1.0 To: Dongsheng Yang , adrian.hunter@intel.com, dedekind1@gmail.com Subject: Re: [PATCH] ubifs: Introduce a mount option of force_atime. References: <1433752038-17276-1-git-send-email-yangds.fnst@cn.fujitsu.com> In-Reply-To: <1433752038-17276-1-git-send-email-yangds.fnst@cn.fujitsu.com> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Am 08.06.2015 um 10:27 schrieb Dongsheng Yang: > Currently, ubifs does not support access time anyway. I understand > that there is a overhead to update inode in each access from user. > > But for the following two reasons, I think we can make it optional > to user. > > (1). More and more flash storage in server are trying to use ubifs, > it is not only for a device such as mobile phone any more, we want > to use it in more and more generic way. Then we need to compete > with some other main filesystems. From this point, access time is > necessary to us, at least as a choice to user currently. Do you have a reference? I know that modern servers use a lot of SSDs which use internally NAND (mostly MLC and TLC). But which systems use RAW NAND where they would care about the atime? > (2). The default mount option about atime is relatime currently, > it's much relaxy compared with strictatime. Then we don't update > the inode in any accessing. So the overhead is not too much. > It's really acceptable. Did you consider ext4's lazytime? I can think of something like that for UBIFS too. Thanks, //richard