From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Sandeen Subject: Re: Documenting MS_LAZYTIME Date: Fri, 20 Feb 2015 09:49:34 -0600 Message-ID: <54E7578E.4090809@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org To: Michael Kerrisk , Theodore Ts'o Cc: Ext4 Developers List , Linux btrfs Developers List , XFS Developers , linux-man@vger.kernel.org, Linux-Fsdevel , Linux API List-Id: linux-api@vger.kernel.org On 2/20/15 2:50 AM, Michael Kerrisk wrote: > Hello Ted, >=20 > Based on your commit message 0ae45f63d4e, I I wrote the documentation > below for MS_LAZYTIME, to go into the mount(2) man page. Could you > please check it over and let me know if it's accurate. In particular, > I added pieces marked with "*" below that were not part of the commit > message and I'd like confirmation that they're accurate. >=20 > Thanks, >=20 > Michael >=20 > [[ > MS_LAZYTIME (since Linux 3.20) > Only update filetimes (atime, mtime, ctime) on the in= - > memory version of the file inode. The on-disk time= =E2=80=90 > stamps are updated only when: "filetimes" and "file inode" seems a bit awkward. How about: > MS_LAZYTIME (since Linux 3.20) > Reduce on-disk updates of inode timestamps (atime, mtime, ctime) > by maintaining these changes only in memory, unless: (maybe I'm bike-shedding too much, if so, sorry). > (a) the inode needs to be updated for some change unre= =E2=80=90 > lated to file timestamps; >=20 > (b) the application employs fsync(2), syncfs(2), o= r > sync(2); >=20 > (c) an undeleted inode is evicted from memory; or >=20 > * (d) more than 24 hours have passed since the i-node wa= s > * written to disk. Please don't use "i-node" - simply "inode" is much more common in the m= anpages AFAICT. > This mount option significantly reduces writes to th= e > inode table for workloads that perform frequent rando= m > writes to preallocated files. This seems like an overly specific description of a single workload out of many which may benefit, but what do others think? "inode table" is = also fairly extN-specific. -Eric =20 > * As at Linux 3.20, this option is supported only on ext4= =2E > ]] >=20 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:46503 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751870AbbBTPto (ORCPT ); Fri, 20 Feb 2015 10:49:44 -0500 Message-ID: <54E7578E.4090809@redhat.com> Date: Fri, 20 Feb 2015 09:49:34 -0600 From: Eric Sandeen MIME-Version: 1.0 To: Michael Kerrisk , "Theodore Ts'o" CC: Ext4 Developers List , Linux btrfs Developers List , XFS Developers , linux-man@vger.kernel.org, Linux-Fsdevel , Linux API Subject: Re: Documenting MS_LAZYTIME References: In-Reply-To: Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2/20/15 2:50 AM, Michael Kerrisk wrote: > Hello Ted, > > Based on your commit message 0ae45f63d4e, I I wrote the documentation > below for MS_LAZYTIME, to go into the mount(2) man page. Could you > please check it over and let me know if it's accurate. In particular, > I added pieces marked with "*" below that were not part of the commit > message and I'd like confirmation that they're accurate. > > Thanks, > > Michael > > [[ > MS_LAZYTIME (since Linux 3.20) > Only update filetimes (atime, mtime, ctime) on the in- > memory version of the file inode. The on-disk time‐ > stamps are updated only when: "filetimes" and "file inode" seems a bit awkward. How about: > MS_LAZYTIME (since Linux 3.20) > Reduce on-disk updates of inode timestamps (atime, mtime, ctime) > by maintaining these changes only in memory, unless: (maybe I'm bike-shedding too much, if so, sorry). > (a) the inode needs to be updated for some change unre‐ > lated to file timestamps; > > (b) the application employs fsync(2), syncfs(2), or > sync(2); > > (c) an undeleted inode is evicted from memory; or > > * (d) more than 24 hours have passed since the i-node was > * written to disk. Please don't use "i-node" - simply "inode" is much more common in the manpages AFAICT. > This mount option significantly reduces writes to the > inode table for workloads that perform frequent random > writes to preallocated files. This seems like an overly specific description of a single workload out of many which may benefit, but what do others think? "inode table" is also fairly extN-specific. -Eric > * As at Linux 3.20, this option is supported only on ext4. > ]] > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 483917F56 for ; Fri, 20 Feb 2015 09:50:03 -0600 (CST) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay2.corp.sgi.com (Postfix) with ESMTP id 182B4304066 for ; Fri, 20 Feb 2015 07:49:59 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id A4ceTtvrkd5MD3E3 (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Fri, 20 Feb 2015 07:49:43 -0800 (PST) Message-ID: <54E7578E.4090809@redhat.com> Date: Fri, 20 Feb 2015 09:49:34 -0600 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: Documenting MS_LAZYTIME References: In-Reply-To: List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Michael Kerrisk , Theodore Ts'o Cc: linux-man@vger.kernel.org, Linux API , XFS Developers , Linux-Fsdevel , Ext4 Developers List , Linux btrfs Developers List T24gMi8yMC8xNSAyOjUwIEFNLCBNaWNoYWVsIEtlcnJpc2sgd3JvdGU6Cj4gSGVsbG8gVGVkLAo+ IAo+IEJhc2VkIG9uIHlvdXIgY29tbWl0IG1lc3NhZ2UgMGFlNDVmNjNkNGUsIEkgSSB3cm90ZSB0 aGUgZG9jdW1lbnRhdGlvbgo+IGJlbG93IGZvciBNU19MQVpZVElNRSwgdG8gZ28gaW50byB0aGUg bW91bnQoMikgbWFuIHBhZ2UuIENvdWxkIHlvdQo+IHBsZWFzZSBjaGVjayBpdCBvdmVyIGFuZCBs ZXQgbWUga25vdyBpZiBpdCdzIGFjY3VyYXRlLiBJbiBwYXJ0aWN1bGFyLAo+IEkgYWRkZWQgcGll Y2VzIG1hcmtlZCB3aXRoICIqIiBiZWxvdyB0aGF0IHdlcmUgbm90IHBhcnQgb2YgdGhlIGNvbW1p dAo+IG1lc3NhZ2UgYW5kIEknZCBsaWtlIGNvbmZpcm1hdGlvbiB0aGF0IHRoZXkncmUgYWNjdXJh dGUuCj4gCj4gVGhhbmtzLAo+IAo+IE1pY2hhZWwKPiAKPiBbWwo+ICAgICAgICBNU19MQVpZVElN RSAoc2luY2UgTGludXggMy4yMCkKPiAgICAgICAgICAgICAgIE9ubHkgIHVwZGF0ZSAgZmlsZXRp bWVzIChhdGltZSwgbXRpbWUsIGN0aW1lKSBvbiB0aGUgaW4tCj4gICAgICAgICAgICAgICBtZW1v cnkgdmVyc2lvbiBvZiB0aGUgZmlsZSAgaW5vZGUuICAgVGhlICBvbi1kaXNrICB0aW1l4oCQCj4g ICAgICAgICAgICAgICBzdGFtcHMgYXJlIHVwZGF0ZWQgb25seSB3aGVuOgoKImZpbGV0aW1lcyIg YW5kICJmaWxlIGlub2RlIiBzZWVtcyBhIGJpdCBhd2t3YXJkLiAgSG93IGFib3V0OgoKPiAgICAg ICAgTVNfTEFaWVRJTUUgKHNpbmNlIExpbnV4IDMuMjApCj4JCVJlZHVjZSBvbi1kaXNrIHVwZGF0 ZXMgb2YgaW5vZGUgdGltZXN0YW1wcyAoYXRpbWUsIG10aW1lLCBjdGltZSkKPiAJCWJ5IG1haW50 YWluaW5nIHRoZXNlIGNoYW5nZXMgb25seSBpbiBtZW1vcnksIHVubGVzczoKCihtYXliZSBJJ20g YmlrZS1zaGVkZGluZyB0b28gbXVjaCwgaWYgc28sIHNvcnJ5KS4KCj4gICAgICAgICAgICAgICAo YSkgIHRoZSBpbm9kZSBuZWVkcyB0byBiZSB1cGRhdGVkIGZvciBzb21lIGNoYW5nZSB1bnJl4oCQ Cj4gICAgICAgICAgICAgICAgICAgIGxhdGVkIHRvIGZpbGUgdGltZXN0YW1wczsKPiAKPiAgICAg ICAgICAgICAgIChiKSAgdGhlIGFwcGxpY2F0aW9uICBlbXBsb3lzICBmc3luYygyKSwgIHN5bmNm cygyKSwgIG9yCj4gICAgICAgICAgICAgICAgICAgIHN5bmMoMik7Cj4gCj4gICAgICAgICAgICAg ICAoYykgIGFuIHVuZGVsZXRlZCBpbm9kZSBpcyBldmljdGVkIGZyb20gbWVtb3J5OyBvcgo+IAo+ ICogICAgICAgICAgICAgKGQpICBtb3JlIHRoYW4gMjQgaG91cnMgaGF2ZSBwYXNzZWQgc2luY2Ug dGhlIGktbm9kZSB3YXMKPiAqICAgICAgICAgICAgICAgICAgd3JpdHRlbiB0byBkaXNrLgoKUGxl YXNlIGRvbid0IHVzZSAiaS1ub2RlIiAtIHNpbXBseSAiaW5vZGUiIGlzIG11Y2ggbW9yZSBjb21t b24gaW4gdGhlIG1hbnBhZ2VzCkFGQUlDVC4KCj4gICAgICAgICAgICAgICBUaGlzIG1vdW50IG9w dGlvbiBzaWduaWZpY2FudGx5IHJlZHVjZXMgIHdyaXRlcyAgdG8gIHRoZQo+ICAgICAgICAgICAg ICAgaW5vZGUgIHRhYmxlICBmb3Igd29ya2xvYWRzIHRoYXQgcGVyZm9ybSBmcmVxdWVudCByYW5k b20KPiAgICAgICAgICAgICAgIHdyaXRlcyB0byBwcmVhbGxvY2F0ZWQgZmlsZXMuCgpUaGlzIHNl ZW1zIGxpa2UgYW4gb3Zlcmx5IHNwZWNpZmljIGRlc2NyaXB0aW9uIG9mIGEgc2luZ2xlIHdvcmts b2FkIG91dApvZiBtYW55IHdoaWNoIG1heSBiZW5lZml0LCBidXQgd2hhdCBkbyBvdGhlcnMgdGhp bms/ICAiaW5vZGUgdGFibGUiIGlzIGFsc28KZmFpcmx5IGV4dE4tc3BlY2lmaWMuCgotRXJpYwog Cj4gKiAgICAgICAgICAgICBBcyBhdCBMaW51eCAzLjIwLCB0aGlzIG9wdGlvbiBpcyBzdXBwb3J0 ZWQgb25seSBvbiBleHQ0Lgo+IF1dCj4gCgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fXwp4ZnMgbWFpbGluZyBsaXN0Cnhmc0Bvc3Muc2dpLmNvbQpodHRwOi8v b3NzLnNnaS5jb20vbWFpbG1hbi9saXN0aW5mby94ZnMK