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From:   "NeilBrown" <neilb@suse.de>
To:     "Mel Gorman" <mgorman@techsingularity.net>
Cc:     "Andrew Morton" <akpm@linux-foundation.org>,
        "Theodore Ts'o" <tytso@mit.edu>,
        "Andreas Dilger" <adilger.kernel@dilger.ca>,
        "Darrick J . Wong" <djwong@kernel.org>,
        "Matthew Wilcox" <willy@infradead.org>,
        "Michal Hocko" <mhocko@suse.com>,
        "Dave Chinner" <david@fromorbit.com>,
        "Rik van Riel" <riel@surriel.com>,
        "Vlastimil Babka" <vbabka@suse.cz>,
        "Johannes Weiner" <hannes@cmpxchg.org>,
        "Jonathan Corbet" <corbet@lwn.net>,
        "Linux-MM" <linux-mm@kvack.org>,
        "Linux-fsdevel" <linux-fsdevel@vger.kernel.org>,
        "LKML" <linux-kernel@vger.kernel.org>,
        "Mel Gorman" <mgorman@techsingularity.net>
Subject: Re: [PATCH v4 0/8] Remove dependency on congestion_wait in mm/
In-reply-to: <20211019090108.25501-1-mgorman@techsingularity.net>
References: <20211019090108.25501-1-mgorman@techsingularity.net>
Date:   Fri, 22 Oct 2021 12:15:10 +1100
Message-id: <163486531001.17149.13533181049212473096@noble.neil.brown.name>
Precedence: bulk

On Tue, 19 Oct 2021, Mel Gorman wrote:
> Changelog since v3
> o Count writeback completions for NR_THROTTLED_WRITTEN only
> o Use IRQ-safe inc_node_page_state
> o Remove redundant throttling
>=20
> This series is also available at
>=20
> git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux.git mm-reclaimconge=
st-v4r2
>=20
> This series that removes all calls to congestion_wait
> in mm/ and deletes wait_iff_congested.=20

Thanks for this.
I don't have sufficient expertise for a positive review, but it seems to
make sense with one exception which I have commented on separately.

In general, I still don't like the use of wake_up_all(), though it won't
cause incorrect behaviour.

I would prefer the first patch would:
 - define NR_VMSCAN_THROTTLE
 - make reclaim_wait an array
 - spelled nr_reclaim_throttled as nr_writeback_throttled

rather than leaving those changes for the second patch.  I think that
would make review easier.

But these are minor and I'll not mention them again.

Thanks,
NeilBrown