From: Wonhyuk Yang <vvghjk1234@gmail.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@techsingularity.net>,
linux-mm@kvack.org
Subject: Re: [PATCH] mm/compactoin: Fix edge case of fast_find_migrateblock()
Date: Tue, 26 Jan 2021 23:37:45 +0900 [thread overview]
Message-ID: <CAEcHRToLN3WfsJzVwKJeq9DmiRo7EJu6Kvcdq_3NVAMdo2CAVg@mail.gmail.com> (raw)
In-Reply-To: <0ed60e73-9c4f-5a62-754d-b3c864239941@suse.cz>
On Tue, Jan 26, 2021 at 1:49 AM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> Maybe instead of replacing one magic value of 'pfn' with another
> (cc->migrate_pfn with high_pfn) I would just add a "bool found" and use it
> appropriately. Would make the function less subtle perhaps.
I agree. Using that bool variable will look good.
>
> While reviewing I found more potentially questionable parts, if you're interested:
>
> - if we go through "if (get_pageblock_skip(freepage))... continue;" we are
> increasing nr_scanned++; but not checking the limit.
Yes, you've got a point. I think nr_scanned checking should be first.
>
> - the "if (list_is_last(freelist, &freepage->lru)) break;" part seems
> unneccesary? if we are on the last page and just "continue;" the
> list_for_each_entry() iteration should stop anyway.
>
Yes It seems unnecessary. only if the skipped block was reordered, it
would be required.
Then I will reflect your opinion and send a new version.
prev parent reply other threads:[~2021-01-26 14:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-23 15:43 Wonhyuk Yang
2021-01-25 16:49 ` Vlastimil Babka
2021-01-26 14:37 ` Wonhyuk Yang [this message]
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