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-rw-r--r--mm/compaction.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index 1ccb015..8f64d35 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -437,6 +437,24 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
if (!valid_page)
valid_page = page;
+
+ /*
+ * For compound pages such as THP and hugetlbfs, we can save
+ * potentially a lot of iterations if we skip them at once.
+ * The check is racy, but we can consider only valid values
+ * and the only danger is skipping too much.
+ */
+ if (PageCompound(page)) {
+ unsigned int comp_order = compound_order(page);
+
+ if (likely(comp_order < MAX_ORDER)) {
+ blockpfn += (1UL << comp_order) - 1;
+ cursor += (1UL << comp_order) - 1;
+ }
+
+ goto isolate_fail;
+ }
+
if (!PageBuddy(page))
goto isolate_fail;
@@ -496,6 +514,13 @@ isolate_fail:
}
+ /*
+ * There is a tiny chance that we have read bogus compound_order(),
+ * so be careful to not go outside of the pageblock.
+ */
+ if (unlikely(blockpfn > end_pfn))
+ blockpfn = end_pfn;
+
trace_mm_compaction_isolate_freepages(*start_pfn, blockpfn,
nr_scanned, total_isolated);
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