59 lines
2.3 KiB
Diff
59 lines
2.3 KiB
Diff
From 025cbf4866306fe4823e8c316c20bdaddc6a0340 Mon Sep 17 00:00:00 2001
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From: Vlastimil Babka <vbabka@suse.cz>
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Date: Fri, 13 Jan 2023 18:33:45 +0100
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Subject: Revert "mm/compaction: fix set skip in fast_find_migrateblock"
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commit 95e7a450b8190673675836bfef236262ceff084a upstream.
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This reverts commit 7efc3b7261030da79001c00d92bc3392fd6c664c.
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We have got openSUSE reports (Link 1) for 6.1 kernel with khugepaged
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stalling CPU for long periods of time. Investigation of tracepoint data
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shows that compaction is stuck in repeating fast_find_migrateblock()
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based migrate page isolation, and then fails to migrate all isolated
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pages.
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Commit 7efc3b726103 ("mm/compaction: fix set skip in fast_find_migrateblock")
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was suspected as it was merged in 6.1 and in theory can indeed remove a
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termination condition for fast_find_migrateblock() under certain
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conditions, as it removes a place that always marks a scanned pageblock
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from being re-scanned. There are other such places, but those can be
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skipped under certain conditions, which seems to match the tracepoint
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data.
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Testing of revert also appears to have resolved the issue, thus revert
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the commit until a more robust solution for the original problem is
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developed.
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It's also likely this will fix qemu stalls with 6.1 kernel reported in
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Link 2, but that is not yet confirmed.
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Link: https://bugzilla.suse.com/show_bug.cgi?id=1206848
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Link: https://lore.kernel.org/kvm/b8017e09-f336-3035-8344-c549086c2340@kernel.org/
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Link: https://lore.kernel.org/lkml/20230125134434.18017-1-mgorman@techsingularity.net/
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Fixes: 7efc3b726103 ("mm/compaction: fix set skip in fast_find_migrateblock")
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Cc: <stable@vger.kernel.org>
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Tested-by: Pedro Falcato <pedro.falcato@gmail.com>
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Acked-by: Mel Gorman <mgorman@techsingularity.net>
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Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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mm/compaction.c | 1 +
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1 file changed, 1 insertion(+)
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diff --git a/mm/compaction.c b/mm/compaction.c
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index ca1603524bbe0..8238e83385a79 100644
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--- a/mm/compaction.c
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+++ b/mm/compaction.c
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@@ -1839,6 +1839,7 @@ static unsigned long fast_find_migrateblock(struct compact_control *cc)
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pfn = cc->zone->zone_start_pfn;
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cc->fast_search_fail = 0;
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found_block = true;
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+ set_pageblock_skip(freepage);
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break;
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}
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}
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--
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cgit
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