Re: Writes blocked on wait_for_stable_page (Writes of less than page size sometimes take too long)

[Nikhilesh Reddy <reddyn@codeaurora.org>]

Thanks so much Darrick and Ted!
You guys have been a lot of help. I really appreciate it.

On Sat 31 Jan 2015 06:37:23 PM PST, Theodore Ts'o wrote:
> On Wed, Jan 28, 2015 at 03:57:05PM -0800, Darrick J. Wong wrote:
>> Yes, that wait_for_page_writeback() was replaced with a call to
>> wait_for_stable_page() upstream, so it'll probably work for your 3.10
>> kernel.
>>
>> (I also wonder why not jump to a newer LTS kernel, but that's neither
>> here nor there.)
>
> Nikhilesh said that he was using a 64-bit android device.  I'm going
> to guess it is based off of the AOSP kernel for the Nexus 9, which is
> a 64-bit android device that uses 3.10 as a base.  It's not *really* a
> 3.10 kernel, though, becausre it looks like bits and pieces of the VFS
> was forward ported to a somewhat newer version so they could backport
> F2FS to the Nexus 9 kernel.  But I'm guessing he's using it because
> there are device drivers he needs that might not be available without
> a lot of forward-porting work on a newer kernel.
>

Yes we cant really move to a newer kernel just yet. :)

> If you are interested in trying to use a somewhat newer version of
> ext4, I just *happen* to have a backport of the 3.18 version of ext4
> on top of a stock version of 3.10.  You can find it at the
> backport-to-3.10 branch of the ext4.git tree on git.kernel.org.

Thanks that is awesome... yes...Will look into them.Thanks!

>
> If you are starting from the AOSP version of the Nexus 9 kernel, the
> patch series from that branch won't apply 100% cleanly, because of the
> changes resulting from the F2FS backport.  It's relatively
> straight-forward though to use the backport-to-3.10 patch series as a
> model to get a version of 3.18 ext4 on top of the AOSP kernel, though;
> it's mostly dropping or reworking patches that were no longer
> necessary thanks to the F2FS backport.
>
> If there is interest, I can look into what might be involved in making
> a git repo of an AOSP kernel with the 3.18 ext4 code backported to it
> available.
>
> I won't give any warrantees, of course, since the AOSP kernel doesn't
> build on x86 and so I can't easily run regression tests on it.  So if
> it breaks, you will get to keep both pieces.  I will try to at least
> look at bug reports, though, and I can say that 3.18 backport on the
> stock 3.10 kernel survives xfstests much better than the 3.10 version
> of ext4, since a modern xfstests very quickly caused the stock 3.10
> kernel to panic.  :-)
>
> 						- Ted
>

Yes I can run testing on my end to make sure everything is good.

Thanks So much once again.

-- 
Thanks
Nikhilesh Reddy

Qualcomm Innovation Center, Inc.
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