Hi Vlastimil,
On Tue, Feb 16, 2021 at 05:39:12PM +0100, Vlastimil Babka wrote:
So, Andrea could you please check if this fixes the original fast_isolate_around() issue for you? With the VM_BUG_ON not removed, DEBUG_VM enabled, no changes to struct page initialization... It relies on pageblock_pfn_to_page as the rest of the compaction code.
Pardon my ignorance of compaction internals, but does this mean that with your patch we'll never call set_pfnblock_flags_mask() for a pfn in a hole?
Thanks!
----8<---- From f5c8d7bc77d2ec0b4cfec44820ce6f602fdb3a86 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka vbabka@suse.cz Date: Tue, 16 Feb 2021 17:32:34 +0100 Subject: [PATCH] mm, compaction: make fast_isolate_around() robust against pfns from a wrong zone
TBD
Signed-off-by: Vlastimil Babka vbabka@suse.cz
mm/compaction.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c index 190ccdaa6c19..b75645e4678d 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1288,7 +1288,7 @@ static void fast_isolate_around(struct compact_control *cc, unsigned long pfn, unsigned long nr_isolated) { unsigned long start_pfn, end_pfn;
- struct page *page = pfn_to_page(pfn);
- struct page *page;
/* Do not search around if there are enough pages already */ if (cc->nr_freepages >= cc->nr_migratepages) @@ -1300,7 +1300,11 @@ fast_isolate_around(struct compact_control *cc, unsigned long pfn, unsigned long /* Pageblock boundaries */ start_pfn = pageblock_start_pfn(pfn);
- end_pfn = min(pageblock_end_pfn(pfn), zone_end_pfn(cc->zone)) - 1;
- end_pfn = min(pageblock_end_pfn(pfn), zone_end_pfn(cc->zone));
- page = pageblock_pfn_to_page(start_pfn, end_pfn, cc->zone);
- if (!page)
return;/* Scan before */ if (start_pfn != pfn) { @@ -1486,7 +1490,7 @@ fast_isolate_freepages(struct compact_control *cc) } cc->total_free_scanned += nr_scanned;
- if (!page)
- if (!page || page_zone(page) != cc->zone) return cc->free_pfn;
low_pfn = page_to_pfn(page); -- 2.30.0