Messages in this thread | | | Date | Wed, 2 Aug 2023 19:31:34 +0800 | Subject | Re: [PATCH v2 4/8] mm/compaction: correct comment of fast_find_migrateblock in isolate_migratepages | From | Baolin Wang <> |
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On 8/2/2023 5:37 PM, Kemeng Shi wrote: > After 90ed667c03fe5 ("Revert "Revert "mm/compaction: fix set skip in > fast_find_migrateblock"""), we remove skip set in fast_find_migrateblock. > Correct comment that fast_find_block is used to avoid isolation_suitable > check for pageblock returned from fast_find_migrateblock because > fast_find_migrateblock will mark found pageblock skipped. > Instead, comment that fast_find_block is used to avoid a redundant check > of fast found pageblock which is already checked skip flag inside > fast_find_migrateblock. > > Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> > --- > mm/compaction.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > index 984c17a5c8fd..5c9dc4049e8e 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -1966,8 +1966,8 @@ static isolate_migrate_t isolate_migratepages(struct compact_control *cc) > block_start_pfn = cc->zone->zone_start_pfn; > > /* > - * fast_find_migrateblock marks a pageblock skipped so to avoid > - * the isolation_suitable check below, check whether the fast > + * fast_find_migrateblock will ignore pageblock skipped, so to avoid
These seem confusing to me, since the fast_find_migrateblock() did not ignore the skip flag checking. So how about below words?
"fast_find_migrateblock() has already ensured the pageblock is not set with a skipped flag, so to avoid the isolation_suitable check below again ..."
> + * the isolation_suitable check below again, check whether the fast > * search was successful. > */ > fast_find_block = low_pfn != cc->migrate_pfn && !cc->fast_search_fail;
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