The patch titled
Subject: ksm: treat unstable nid like in stable tree
has been added to the -mm tree. Its filename is
ksm-treat-unstable-nid-like-in-stable-tree.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: ksm: treat unstable nid like in stable tree
An inconsistency emerged in reviewing the NUMA node changes to KSM: when
meeting a page from the wrong NUMA node in a stable tree, we say that it's
okay for comparisons, but not as a leaf for merging; whereas when meeting
a page from the wrong NUMA node in an unstable tree, we bail out
immediately.
Now, it might be that a wrong NUMA node in an unstable tree is more likely
to correlate with instablility (different content, with rbnode now
misplaced) than page migration; but even so, we are accustomed to
instablility in the unstable tree.
Without strong evidence for which strategy is generally better, I'd rather
be consistent with what's done in the stable tree: accept a page from the
wrong NUMA node for comparison, but not as a leaf for merging.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Petr Holasek <pholasek@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Izik Eidus <izik.eidus@xxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/ksm.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff -puN mm/ksm.c~ksm-treat-unstable-nid-like-in-stable-tree mm/ksm.c
--- a/mm/ksm.c~ksm-treat-unstable-nid-like-in-stable-tree
+++ a/mm/ksm.c
@@ -1342,16 +1342,6 @@ struct rmap_item *unstable_tree_search_i
return NULL;
}
- /*
- * If tree_page has been migrated to another NUMA node, it
- * will be flushed out and put into the right unstable tree
- * next time: only merge with it if merge_across_nodes.
- */
- if (!ksm_merge_across_nodes && page_to_nid(tree_page) != nid) {
- put_page(tree_page);
- return NULL;
- }
-
ret = memcmp_pages(page, tree_page);
parent = *new;
@@ -1361,6 +1351,15 @@ struct rmap_item *unstable_tree_search_i
} else if (ret > 0) {
put_page(tree_page);
new = &parent->rb_right;
+ } else if (!ksm_merge_across_nodes &&
+ page_to_nid(tree_page) != nid) {
+ /*
+ * If tree_page has been migrated to another NUMA node,
+ * it will be flushed out and put in the right unstable
+ * tree next time: only merge with it when across_nodes.
+ */
+ put_page(tree_page);
+ return NULL;
} else {
*tree_pagep = tree_page;
return tree_rmap_item;
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
origin.patch
linux-next.patch
revert-x86-mm-make-spurious_fault-check-explicitly-check-the-present-bit.patch
pageattr-prevent-pse-and-gloabl-leftovers-to-confuse-pmd-pte_present-and-pmd_huge.patch
mm-memcg-only-evict-file-pages-when-we-have-plenty.patch
mm-vmscan-save-work-scanning-almost-empty-lru-lists.patch
mm-vmscan-clarify-how-swappiness-highest-priority-memcg-interact.patch
mm-vmscan-improve-comment-on-low-page-cache-handling.patch
mm-vmscan-clean-up-get_scan_count.patch
mm-vmscan-clean-up-get_scan_count-fix.patch
mm-vmscan-compaction-works-against-zones-not-lruvecs.patch
mm-vmscan-compaction-works-against-zones-not-lruvecs-fix.patch
mm-reduce-rmap-overhead-for-ex-ksm-page-copies-created-on-swap-faults.patch
mm-page_allocc-__setup_per_zone_wmarks-make-min_pages-unsigned-long.patch
mm-vmscanc-__zone_reclaim-replace-max_t-with-max.patch
mmksm-use-new-hashtable-implementation.patch
mm-make-madvisemadv_willneed-support-swap-file-prefetch.patch
mm-make-madvisemadv_willneed-support-swap-file-prefetch-fix.patch
mm-make-madvisemadv_willneed-support-swap-file-prefetch-fix-fix.patch
mm-avoid-calling-pgdat_balanced-needlessly.patch
mm-numa-fix-minor-typo-in-numa_next_scan.patch
mm-numa-take-thp-into-account-when-migrating-pages-for-numa-balancing.patch
mm-numa-handle-side-effects-in-count_vm_numa_events-for-config_numa_balancing.patch
mm-move-page-flags-layout-to-separate-header.patch
mm-fold-page-_last_nid-into-page-flags-where-possible.patch
mm-numa-cleanup-flow-of-transhuge-page-migration.patch
mm-dont-inline-page_mapping.patch
swap-make-each-swap-partition-have-one-address_space.patch
swap-make-each-swap-partition-have-one-address_space-fix.patch
swap-make-each-swap-partition-have-one-address_space-fix-fix.patch
swap-add-per-partition-lock-for-swapfile.patch
swap-add-per-partition-lock-for-swapfile-fix-fix-fix.patch
memcg-reduce-the-size-of-struct-memcg-244-fold.patch
memcg-reduce-the-size-of-struct-memcg-244-fold-fix.patch
ksm-allow-trees-per-numa-node.patch
ksm-add-sysfs-abi-documentation.patch
ksm-trivial-tidyups.patch
ksm-trivial-tidyups-fix.patch
ksm-reorganize-ksm_check_stable_tree.patch
ksm-get_ksm_page-locked.patch
ksm-remove-old-stable-nodes-more-thoroughly.patch
ksm-make-ksm-page-migration-possible.patch
ksm-make-merge_across_nodes-migration-safe.patch
ksm-enable-ksm-page-migration.patch
mm-remove-offlining-arg-to-migrate_pages.patch
ksm-stop-hotremove-lockdep-warning.patch
mm-shmem-use-new-radix-tree-iterator.patch
mm-mlockc-document-scary-looking-stack-expansion-mlock-chain.patch
mmu_notifier_unregister-null-pointer-deref-and-multiple-release-callouts.patch
mm-use-up-free-swap-space-before-reaching-oom-kill.patch
memcg-stop-warning-on-memcg_propagate_kmem.patch
mm-use-long-type-for-page-counts-in-mm_populate-and-get_user_pages.patch
mm-accelerate-mm_populate-treatment-of-thp-pages.patch
mm-accelerate-munlock-treatment-of-thp-pages.patch
tmpfs-fix-use-after-free-of-mempolicy-object.patch
tmpfs-fix-mempolicy-object-leaks.patch
tmpfs-fix-mempolicy-object-leaks-fix.patch
ksm-add-some-comments.patch
ksm-treat-unstable-nid-like-in-stable-tree.patch
ksm-shrink-32-bit-rmap_item-back-to-32-bytes.patch
mmksm-foll_migration-do-migration_entry_wait.patch
mmksm-swapoff-might-need-to-copy.patch
mm-cleanup-swapcache-in-do_swap_page.patch
ksm-allocate-roots-when-needed.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
