linux-kernel - 答复: 答复: [PATCH] fs-writeback: writeback_sb_inodes: Do not increase 'total

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Message-ID: <TY2PR06MB33421220C2F01F8E537CED5CBEF5A@TY2PR06MB3342.apcprd06.prod.outlook.com>
Date:   Sat, 16 Sep 2023 06:01:32 +0000
From:   Chunhai Guo <guochunhai@...o.com>
To:     Jan Kara <jack@...e.cz>
CC:     "chao@...nel.org" <chao@...nel.org>,
        "jaegeuk@...nel.org" <jaegeuk@...nel.org>,
        "brauner@...nel.org" <brauner@...nel.org>,
        "viro@...iv.linux.org.uk" <viro@...iv.linux.org.uk>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: 答复: 答复: [PATCH] fs-writeback: writeback_sb_inodes: Do not increase 'total_wrote' when nothing is written

> >>> On Wed 13-09-23 07:15:01, Chunhai Guo wrote:
> >>>>  From the dump info, there are only two pages as shown below. One
> >>>> is updated and another is under writeback. Maybe f2fs counts the
> >>>> writeback page as a dirty one, so get_dirty_pages() got one. As you
> >>>> said, maybe this is unreasonable.
> >>>>
> >>>> Jaegeuk & Chao, what do you think of this?
> >>>>
> >>>>
> >>>> crash_32> files -p 0xE5A44678
> >>>>   INODE    NRPAGES
> >>>> e5a44678        2
> >>>>
> >>>>    PAGE    PHYSICAL   MAPPING    INDEX CNT FLAGS
> >>>> e8d0e338  641de000  e5a44810         0  5 a095
> >>> locked,waiters,uptodate,lru,private,writeback
> >>>> e8ad59a0  54528000  e5a44810         1  2 2036
> >>> referenced,uptodate,lru,active,private
> >>>
> >>> Indeed, incrementing pages_skipped when there's no dirty page is a bit odd.
> >>> That being said we could also harden requeue_inode() - in particular
> >>> we could do
> >>> there:
> >>>
> >>>          if (wbc->pages_skipped) {
> >>>                  /*
> >>>                   * Writeback is not making progress due to locked buffers.
> >>>                   * Skip this inode for now. Although having skipped pages
> >>>                   * is odd for clean inodes, it can happen for some
> >>>                   * filesystems so handle that gracefully.
> >>>                   */
> >>>                  if (inode->i_state & I_DIRTY_ALL)
> >>>                          redirty_tail_locked(inode, wb);
> >>>                  else
> >>>                          inode_cgwb_move_to_attached(inode, wb);
> >>>          }
> >>>
> >>> Does this fix your problem as well?
> >>>
> >>>
> >>> Honza
> >>
> >> Thank you for your reply. Did you forget the 'return' statement? Since I
> encountered this issue on the 4.19 kernel and there is not
> inode_cgwb_move_to_attached() yet, I replaced it with
> inode_io_list_del_locked(). So, below is the test patch I am applying. Please
> have a check. By the way, the test will take some time. I will provide feedback
> when it is finished. Thanks.
> >
> > Yeah, I forgot about the return.
> 
> Hi Jan,
> The test is finished and this patch can fix this issue, too.
> Thanks,

Hi Jan,
I have send the patch as you suggested.
Thanks,

> >> 	if (wbc->pages_skipped) {
> >> 		/*
> >> 		 * writeback is not making progress due to locked
> >> 		 * buffers. Skip this inode for now.
> >> 		 */
> >> -		redirty_tail_locked(inode, wb);
> >> +		if (inode->i_state & I_DIRTY_ALL)
> >> +			redirty_tail_locked(inode, wb);
> >> +		else
> >> +			inode_io_list_del_locked(inode, wb);
> >>   		return;
> >>   	}
> >
> > Looks good. Thanks for testing!
> >
> > 								Honza