Re: [PATCH v4 0/8] Remove dependency on congestion_wait in mm/

[NeilBrown]

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
> 
> This series is also available at
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux.git mm-reclaimcongest-v4r2
> 
> This series that removes all calls to congestion_wait
> in mm/ and deletes wait_iff_congested. 

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