From: Tejun Heo <tj@kernel.org>
To: Jan Kara <jack@suse.cz>
Cc: dsterba@suse.com, clm@fb.com, josef@toxicpanda.com,
axboe@kernel.dk, linux-btrfs@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
kernel-team@fb.com
Subject: Re: [PATCH 2/9] blkcg, writeback: Add wbc->no_wbc_acct
Date: Thu, 20 Jun 2019 10:02:50 -0700 [thread overview]
Message-ID: <20190620170250.GL657710@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <20190620152145.GL30243@quack2.suse.cz>
Hello, Jan.
On Thu, Jun 20, 2019 at 05:21:45PM +0200, Jan Kara wrote:
> I'm completely ignorant of how btrfs compressed writeback works so don't
> quite understand implications of this. So does this mean that writeback to
> btrfs compressed files won't be able to transition inodes from one memcg to
> another? Or are you trying to say the 'wbc' used from async worker thread
> is actually a dummy one and we would double-account the writeback?
So, before, only the async compression workers would run through the
wbc accounting code regardless of who originated the dirty pages,
which is obviously wrong. After the patch, the code accounts when the
dirty pages are being handed off to the compression workers and
no_wbc_acct is used to suppress spurious accounting from the workers.
> Anyway, AFAICS no_wbc_acct means: "IO done as a result of this wbc will not
> have influence on inode memcg ownership", doesn't it?
Yeap.
Thanks.
--
tejun
next prev parent reply other threads:[~2019-06-20 17:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-15 18:24 [PATCHSET v2 btrfs/for-next] blkcg, btrfs: fix cgroup writeback support Tejun Heo
2019-06-15 18:24 ` [PATCH 1/9] cgroup, blkcg: Prepare some symbols for module and !CONFIG_CGROUP usages Tejun Heo
2019-06-24 16:39 ` Jan Kara
2019-06-15 18:24 ` [PATCH 2/9] blkcg, writeback: Add wbc->no_wbc_acct Tejun Heo
2019-06-20 15:21 ` Jan Kara
2019-06-20 17:02 ` Tejun Heo [this message]
2019-06-24 8:21 ` Jan Kara
2019-06-24 12:58 ` Tejun Heo
2019-06-24 16:39 ` Jan Kara
2019-06-24 16:49 ` Jan Kara
2019-06-15 18:24 ` [PATCH 3/9] blkcg, writeback: Implement wbc_blkcg_css() Tejun Heo
2019-06-24 16:50 ` Jan Kara
2019-06-15 18:24 ` [PATCH 4/9] blkcg: implement REQ_CGROUP_PUNT Tejun Heo
2019-06-15 18:29 ` Tejun Heo
2019-06-20 15:37 ` Jan Kara
2019-06-20 16:42 ` Tejun Heo
2019-06-20 17:01 ` Jan Kara
2019-06-24 16:53 ` Jan Kara
2019-06-15 18:24 ` [PATCH 5/9] Btrfs: stop using btrfs_schedule_bio() Tejun Heo
2019-06-15 18:24 ` [PATCH 6/9] Btrfs: delete the entire async bio submission framework Tejun Heo
2019-06-15 18:24 ` [PATCH 7/9] Btrfs: only associate the locked page with one async_cow struct Tejun Heo
2019-06-15 18:24 ` [PATCH 8/9] Btrfs: use REQ_CGROUP_PUNT for worker thread submitted bios Tejun Heo
2019-06-15 18:24 ` [PATCH 9/9] Btrfs: extent_write_locked_range() should attach inode->i_wb Tejun Heo
2019-06-18 12:54 ` [PATCHSET v2 btrfs/for-next] blkcg, btrfs: fix cgroup writeback support David Sterba
2019-06-18 14:45 ` Tejun Heo
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