From: Tejun Heo <tj@kernel.org>
To: Liz Fong-Jones <lizf@honeycomb.io>
Cc: Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jens Axboe <axboe@kernel.dk>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Xin Yin <yinxin.x@bytedance.com>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
ian@honeycomb.io
Subject: Re: [PATCH v4 1/2] writeback: let foreign flushes reach dying cgwbs
Date: Thu, 01 Oct 2026 08:43:41 -1000 [thread overview]
Message-ID: <f5e9ef4614d5f9ca4b7fe6420dbf8454@kernel.org> (raw)
In-Reply-To: <20260930-wb-dying-cgwb-flush-v4-1-bde637803a96@honeycomb.io>
Hello, Liz.
On Wed, Sep 30, 2026 at 07:35:37PM +0000, Liz Fong-Jones wrote:
> if (test_bit(WB_registered, &bdi->wb.state) &&
> - blkcg_cgwb_list->next && memcg_cgwb_list->next) {
> + blkcg_cgwb_list->next && memcg_cgwb_list->next &&
> + !css_is_dying(memcg_css)) {
With patch 2 switching a replaced wb's inodes to its successor instead of
flushing them in place, this doesn't matter anymore. If a removed memcg's
wb gets replaced, the successor takes over the inodes and stays in the
tree until released, so foreign flushes still reach them. I asked for it
against v3, where patch 2 only kicked writeback on the old wb. Can you
drop it and the description sentence about it?
Thanks.
--
tejun
next prev parent reply other threads:[~2026-10-01 18:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-30 19:35 [PATCH v4 0/2] writeback: let foreign flushes reach dying cgwbs Liz Fong-Jones
2026-09-30 19:35 ` [PATCH v4 1/2] " Liz Fong-Jones
2026-10-01 18:43 ` Tejun Heo [this message]
2026-09-30 19:35 ` [PATCH v4 2/2] writeback: switch a replaced cgwb's inodes to its successor Liz Fong-Jones
2026-10-01 18:43 ` Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f5e9ef4614d5f9ca4b7fe6420dbf8454@kernel.org \
--to=tj@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=brauner@kernel.org \
--cc=cgroups@vger.kernel.org \
--cc=hannes@cmpxchg.org \
--cc=ian@honeycomb.io \
--cc=jack@suse.cz \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lizf@honeycomb.io \
--cc=roman.gushchin@linux.dev \
--cc=shakeel.butt@linux.dev \
--cc=viro@zeniv.linux.org.uk \
--cc=yinxin.x@bytedance.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.