The patch titled
From: Hillf Danton <dhillf@xxxxxxxxx>
has been added to the -mm tree. Its filename is
mm-hugetlb-defer-freeing-pages-when-gathering-surplus-pages.patch
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From: Hillf Danton <dhillf@xxxxxxxxx>
Subject: mm: hugetlb: defer freeing pages when gathering surplus pages
When gathering surplus pages, the number of needed pages is recomputed
after reacquiring hugetlb lock to catch changes in resv_huge_pages and
free_huge_pages. Plus it is recomputed with the number of newly allocated
pages involved.
Thus freeing pages can be deferred a bit to see if the final page request
is satisfied, though pages could be allocated less than needed.
Signed-off-by: Hillf Danton <dhillf@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)
diff -puN mm/hugetlb.c~mm-hugetlb-defer-freeing-pages-when-gathering-surplus-pages mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlb-defer-freeing-pages-when-gathering-surplus-pages
+++ a/mm/hugetlb.c
@@ -852,6 +852,7 @@ static int gather_surplus_pages(struct h
struct page *page, *tmp;
int ret, i;
int needed, allocated;
+ bool alloc_ok = true;
needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
if (needed <= 0) {
@@ -867,17 +868,13 @@ retry:
spin_unlock(&hugetlb_lock);
for (i = 0; i < needed; i++) {
page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
- if (!page)
- /*
- * We were not able to allocate enough pages to
- * satisfy the entire reservation so we free what
- * we've allocated so far.
- */
- goto free;
-
+ if (!page) {
+ alloc_ok = false;
+ break;
+ }
list_add(&page->lru, &surplus_list);
}
- allocated += needed;
+ allocated += i;
/*
* After retaking hugetlb_lock, we need to recalculate 'needed'
@@ -886,9 +883,16 @@ retry:
spin_lock(&hugetlb_lock);
needed = (h->resv_huge_pages + delta) -
(h->free_huge_pages + allocated);
- if (needed > 0)
- goto retry;
-
+ if (needed > 0) {
+ if (alloc_ok)
+ goto retry;
+ /*
+ * We were not able to allocate enough pages to
+ * satisfy the entire reservation so we free what
+ * we've allocated so far.
+ */
+ goto free;
+ }
/*
* The surplus_list now contains _at_least_ the number of extra pages
* needed to accommodate the reservation. Add the appropriate number
@@ -914,10 +918,10 @@ retry:
VM_BUG_ON(page_count(page));
enqueue_huge_page(h, page);
}
+free:
spin_unlock(&hugetlb_lock);
/* Free unnecessary surplus pages to the buddy allocator */
-free:
if (!list_empty(&surplus_list)) {
list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
list_del(&page->lru);
_
Subject: From: Hillf Danton <dhillf@xxxxxxxxx>
Patches currently in -mm which might be from dhillf@xxxxxxxxx are
mm-vmscanc-cleanup-with-s-reclaim_mode-isolate_mode.patch
mm-vmscan-fix-misused-nr_reclaimed-in-shrink_mem_cgroup_zone.patch
vmscan-reclaim-at-order-0-when-compaction-is-enabled.patch
vmscan-kswapd-carefully-call-compaction.patch
vmscan-kswapd-carefully-call-compaction-fix.patch
vmscan-only-defer-compaction-for-failed-order-and-higher.patch
hugetlbfs-fix-hugetlb_get_unmapped_area.patch
hugetlb-drop-prev_vma-in-hugetlb_get_unmapped_area_topdown.patch
hugetlb-try-to-search-again-if-it-is-really-needed.patch
hugetlb-try-to-search-again-if-it-is-really-needed-fix.patch
mm-do-not-reset-cached_hole_size-when-vma-is-unmapped.patch
mm-search-from-free_area_cache-for-the-bigger-size.patch
mm-hugetlb-defer-freeing-pages-when-gathering-surplus-pages.patch
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