On Mon, 30 Mar 2015 14:31:14 -0400 Eric B Munson <emunson@xxxxxxxxxx> wrote: > The memory compaction code uses the migration code to do most of the > work in compaction. However, the compaction code interacts with the > unevictable LRU differently than migration code and this difference > should be noted in the documentation. > > --- a/Documentation/vm/unevictable-lru.txt > +++ b/Documentation/vm/unevictable-lru.txt > @@ -450,6 +451,16 @@ list because of a race between munlock and migration, page migration uses the > putback_lru_page() function to add migrated pages back to the LRU. > > > +COMPACTING MLOCKED PAGES > +------------------------ > + > +The unevictable LRU can be scanned for compactable regions and the default > +behavior is to do so. There is a sysctl to control this behavior (see > +Documentation/sysctl/vm.txt). Once scanning of the unevictable LRU is > +enabled, the work of compaction is mostly handled by the page migration code > +and the same work flow as described in MIGRATING MLOCKED PAGES will apply. > + Thanks. Let's tell people what this sysctl is called? s@There is a sysctl to control@/proc/sys/vm/compact_unevictable_allowed controls@: --- a/Documentation/vm/unevictable-lru.txt~document-interaction-between-compaction-and-the-unevictable-lru-fix +++ a/Documentation/vm/unevictable-lru.txt @@ -455,10 +455,11 @@ COMPACTING MLOCKED PAGES ------------------------ The unevictable LRU can be scanned for compactable regions and the default -behavior is to do so. There is a sysctl to control this behavior (see -Documentation/sysctl/vm.txt). Once scanning of the unevictable LRU is -enabled, the work of compaction is mostly handled by the page migration code -and the same work flow as described in MIGRATING MLOCKED PAGES will apply. +behavior is to do so. /proc/sys/vm/compact_unevictable_allowed controls +this behavior (see Documentation/sysctl/vm.txt). Once scanning of the +unevictable LRU is enabled, the work of compaction is mostly handled by +the page migration code and the same work flow as described in MIGRATING +MLOCKED PAGES will apply. mmap(MAP_LOCKED) SYSTEM CALL HANDLING _ -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
