linux-kernel - Re: [PATCH 0/11] Per-bdi writeback flusher threads #4

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Date:	Tue, 19 May 2009 08:20:50 +0200
From:	Jens Axboe <jens.axboe@...cle.com>
To:	"Zhang, Yanmin" <yanmin_zhang@...ux.intel.com>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	chris.mason@...cle.com, david@...morbit.com, hch@...radead.org,
	akpm@...ux-foundation.org, jack@...e.cz
Subject: Re: [PATCH 0/11] Per-bdi writeback flusher threads #4

On Tue, May 19 2009, Zhang, Yanmin wrote:
> On Mon, 2009-05-18 at 14:19 +0200, Jens Axboe wrote:
> > Hi,
> > 
> > This is the fourth version of this patchset. Chances since v3:
> > 
> > - Dropped a prep patch, it has been included in mainline since.
> > 
> > - Add a work-to-do list to the bdi. This is struct bdi_work. Each
> >   wb thread will notice and execute work on bdi->work_list. The arguments
> >   are which sb (or NULL for all) to flush and how many pages to flush.
> > 
> > - Fix a bug where not all bdi's would end up on the bdi_list, so potentially
> >   some data would not be flushed.
> > 
> > - Make wb_kupdated() pass on wbc->older_than_this so we maintain the same
> >   behaviour for kupdated flushes.
> > 
> > - Have the wb thread flush first before sleeping, to avoid losing the
> >   first flush on lazy register.
> > 
> > - Rebase to newer kernels.
> Jens,
> 
> Applied V4 to 2.6.30-rc6 and got some confliction reports.
> ----------patch-2----------
> patching file fs/buffer.c
> patching file fs/fs-writeback.c
> patching file fs/ntfs/super.c
> patching file fs/sync.c
> patching file include/linux/backing-dev.h
> patching file include/linux/fs.h
> patching file include/linux/writeback.h
> patching file mm/backing-dev.c
> patching file mm/page-writeback.c
> Hunk #5 FAILED at 666.
> 1 out of 6 hunks FAILED -- saving rejects to file mm/page-writeback.c.rej
> patching file mm/vmscan.c
> ----------patch-3----------
> patching file fs/fs-writeback.c
> patching file include/linux/writeback.h
> patching file mm/Makefile
> patching file mm/pdflush.c
> ----------patch-4----------
> patching file fs/fs-writeback.c
> patching file include/linux/backing-dev.h
> patching file mm/backing-dev.c
> ----------patch-5----------
> patching file fs/fs-writeback.c
> patching file include/linux/backing-dev.h
> patching file include/linux/fs.h
> patching file mm/backing-dev.c
> patching file mm/page-writeback.c
> Hunk #1 succeeded at 708 with fuzz 2 (offset 41 lines).
> Hunk #2 FAILED at 716.
> 1 out of 2 hunks FAILED -- saving rejects to file mm/page-writeback.c.rej

It's not against -rc6, it's against current -git. And current -git had a
one-liner fixup to the centisec calculation, so it'll fail. If you apply
the below patch to -rc6, then the series should apply cleanly on top of
that.

> Then, I manually fixed the conflictions, but compilation reports errors.
> Your patches seem not clean.
> 
>   CC      fs/exec.o
> mm/page-writeback.c: In function 'background_writeout':
> mm/page-writeback.c:695: error: 'MAX_WRITEBACK_PAGES' undeclared (first use in this function)
> mm/page-writeback.c:695: error: (Each undeclared identifier is reported only once
> mm/page-writeback.c:695: error: for each function it appears in.)
> mm/page-writeback.c: In function 'wb_kupdate':
> mm/page-writeback.c:769: error: 'MAX_WRITEBACK_PAGES' undeclared (first use in this function)
> mm/page-writeback.c: In function 'wb_timer_fn':
> mm/page-writeback.c:802: error: implicit declaration of function 'pdflush_operation'
> make[1]: *** [mm/page-writeback.o] Error 1
> make[1]: *** Waiting for unfinished jobs....
>   CC      fs/pipe.o

You still have remnants of pdflush, so there's definite something wrong
with your manual patching :-)

I'm attaching two patches - apply #1 to -rc6, and then #2 is a roll-up
of the patch series that you can apply next.

-- 
Jens Axboe


View attachment "writeback-fix.patch" of type "text/x-diff" (2003 bytes)

View attachment "writeback-20090519" of type "text/plain" (74973 bytes)