Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754878AbaG3DMy (ORCPT ); Tue, 29 Jul 2014 23:12:54 -0400 Received: from mail.kernel.org ([198.145.19.201]:56589 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754521AbaG3DMx (ORCPT ); Tue, 29 Jul 2014 23:12:53 -0400 Date: Tue, 29 Jul 2014 20:13:15 -0700 From: Jaegeuk Kim To: Chao Yu Cc: "'Changman Lee'" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH 07/11] f2fs: enable in-place-update for fdatasync Message-ID: <20140730031315.GB99885@jaegeuk-mac02> References: <1406328445-63707-1-git-send-email-jaegeuk@kernel.org> <1406328445-63707-7-git-send-email-jaegeuk@kernel.org> <20140729004111.GA442@lcm> <20140729122215.GB84378@jaegeuk-mac02> <20140729235455.GB442@lcm> <20140730010821.GA98706@jaegeuk-mac02> <00a501cfaba0$76077130$62165390$@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <00a501cfaba0$76077130$62165390$@samsung.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 30, 2014 at 10:45:38AM +0800, Chao Yu wrote: > Hi Jaegeuk Changman, > > > -----Original Message----- > > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org] > > Sent: Wednesday, July 30, 2014 9:08 AM > > To: Changman Lee > > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; > > linux-f2fs-devel@lists.sourceforge.net > > Subject: Re: [f2fs-dev] [PATCH 07/11] f2fs: enable in-place-update for fdatasync > > > > On Wed, Jul 30, 2014 at 08:54:55AM +0900, Changman Lee wrote: > > > On Tue, Jul 29, 2014 at 05:22:15AM -0700, Jaegeuk Kim wrote: > > > > Hi Changman, > > > > > > > > On Tue, Jul 29, 2014 at 09:41:11AM +0900, Changman Lee wrote: > > > > > Hi Jaegeuk, > > > > > > > > > > On Fri, Jul 25, 2014 at 03:47:21PM -0700, Jaegeuk Kim wrote: > > > > > > This patch enforces in-place-updates only when fdatasync is requested. > > > > > > If we adopt this in-place-updates for the fdatasync, we can skip to write the > > > > > > recovery information. > > > > > > > > > > But, as you know, random write occurs when changing into in-place-updates. > > > > > It will degrade write performance. Is there any case in-place-updates is > > > > > better, except recovery or high utilization? > > > > > > > > As I described, you can easily imagine, if users requested small amount of data > > > > writes with fdatasync, we should do data writes + node writes. > > > > But, if we can do in-place-update, we don't need to write node blocks. > > > > Surely it triggers random writes, however, the amount of data is preety small > > > > and the device handles them very fast by its inside cache, so that it can > > > > enhance the performance. > > > > > > > > Thanks, > > > > > > Partially agree. Sometimes, I see that SSR shows lower performance than > > > IPU. One of the reasons might be node writes. > > > > What did you mean? That's why I consider IPU eagarly instead of SSR and LFS > > under the very strict cases. > > > > > Anyway, if so, we should know total dirty pages for fdatasync and it's very > > > tunable according to a random write performance of device. > > > > Agreed. We can do that either by comparing the number of dirty pages, > > additional data/node writes, and cost of checkpoint at the same time. > > And there is another thing is that we need to consider the number of > > waiting time for end_io. > > I'll look into this at some time. > > Agreed, but please additionally consider that the number we got is not highly > accurate because without protection of ->i_mutex writer could generate more > dirty pages. Right, but IMO, it doesn't need to get correct numbers. Just for reference is enough. Sort of trade-offs. :) Thanks, > > > > > Thanks, > > > > > > > > Thanks, > > > > > > > > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > > Signed-off-by: Jaegeuk Kim > > > > > > --- > > > > > > fs/f2fs/f2fs.h | 1 + > > > > > > fs/f2fs/file.c | 7 +++++++ > > > > > > fs/f2fs/segment.h | 4 ++++ > > > > > > 3 files changed, 12 insertions(+) > > > > > > > > > > > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > > > > > > index ab36025..8f8685e 100644 > > > > > > --- a/fs/f2fs/f2fs.h > > > > > > +++ b/fs/f2fs/f2fs.h > > > > > > @@ -998,6 +998,7 @@ enum { > > > > > > FI_INLINE_DATA, /* used for inline data*/ > > > > > > FI_APPEND_WRITE, /* inode has appended data */ > > > > > > FI_UPDATE_WRITE, /* inode has in-place-update data */ > > > > > > + FI_NEED_IPU, /* used fo ipu for fdatasync */ > > > > > > }; > > > > > > > > > > > > static inline void set_inode_flag(struct f2fs_inode_info *fi, int flag) > > > > > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > > > > > > index 121689a..e339856 100644 > > > > > > --- a/fs/f2fs/file.c > > > > > > +++ b/fs/f2fs/file.c > > > > > > @@ -127,11 +127,18 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, > > int datasync) > > > > > > return 0; > > > > > > > > > > > > trace_f2fs_sync_file_enter(inode); > > > > > > + > > > > > > + /* if fdatasync is triggered, let's do in-place-update */ > > > > > > + if (datasync) > > > > > > + set_inode_flag(fi, FI_NEED_IPU); > > > > > > + > > > > > > ret = filemap_write_and_wait_range(inode->i_mapping, start, end); > > > > > > if (ret) { > > > > > > trace_f2fs_sync_file_exit(inode, need_cp, datasync, ret); > > > > > > return ret; > > > > > > } > > > > > > + if (datasync) > > > > > > + clear_inode_flag(fi, FI_NEED_IPU); > > > > > > > > > > > > /* > > > > > > * if there is no written data, don't waste time to write recovery info. > > > > > > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > > > > > > index ee5c75e..55973f7 100644 > > > > > > --- a/fs/f2fs/segment.h > > > > > > +++ b/fs/f2fs/segment.h > > > > > > @@ -486,6 +486,10 @@ static inline bool need_inplace_update(struct inode *inode) > > > > > > if (S_ISDIR(inode->i_mode)) > > > > > > return false; > > > > > > > > > > > > + /* this is only set during fdatasync */ > > > > > > + if (is_inode_flag_set(F2FS_I(inode), FI_NEED_IPU)) > > > > > > + return true; > > > > > > + > > > > > > switch (SM_I(sbi)->ipu_policy) { > > > > > > case F2FS_IPU_FORCE: > > > > > > return true; > > > > > > -- > > > > > > 1.8.5.2 (Apple Git-48) > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------------ > > > > > > Want fast and easy access to all the code in your enterprise? Index and > > > > > > search up to 200,000 lines of code with a free copy of Black Duck > > > > > > Code Sight - the same software that powers the world's largest code > > > > > > search on Ohloh, the Black Duck Open Hub! Try it now. > > > > > > http://p.sf.net/sfu/bds > > > > > > _______________________________________________ > > > > > > Linux-f2fs-devel mailing list > > > > > > Linux-f2fs-devel@lists.sourceforge.net > > > > > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > > > > ------------------------------------------------------------------------------ > > Infragistics Professional > > Build stunning WinForms apps today! > > Reboot your WinForms applications with our WinForms controls. > > Build a bridge from your legacy apps to the future. > > http://pubads.g.doubleclick.net/gampad/clk?id=153845071&iu=/4140/ostg.clktrk > > _______________________________________________ > > Linux-f2fs-devel mailing list > > Linux-f2fs-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/