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Date:   Wed, 12 Feb 2020 14:24:35 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Minchan Kim <minchan@kernel.org>
Cc:     Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
        linux-mm <linux-mm@kvack.org>,
        Josef Bacik <josef@toxicpanda.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: fix long time stall from mm_populate
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On Wed, 12 Feb 2020 11:53:22 -0800 Minchan Kim <minchan@kernel.org> wrote:

> > That's definitely wrong.  It'll clear PageReclaim and then pretend it did
> > nothing wrong.
> > 
> > 	return !PageWriteback(page) ||
> > 		test_and_clear_bit(PG_reclaim, &page->flags);
> > 
> 
> Much better, Thanks for the review, Matthew!
> If there is no objection, I will send two patches to Andrew.
> One is PageReadahead strict, the other is limit retry from mm_populate.

With much more detailed changelogs, please!

This all seems rather screwy.  if a page is under writeback then it is
uptodate and we should be able to fault it in immediately.