diff options
| -rw-r--r-- | Documentation/sysctl/vm.txt | 11 | ||||
| -rw-r--r-- | include/linux/compaction.h | 1 | ||||
| -rw-r--r-- | kernel/sysctl.c | 9 | ||||
| -rw-r--r-- | mm/compaction.c | 7 |
4 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 902b4574acfb..9832ec52f859 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -21,6 +21,7 @@ Currently, these files are in /proc/sys/vm: - admin_reserve_kbytes - block_dump - compact_memory +- compact_unevictable_allowed - dirty_background_bytes - dirty_background_ratio - dirty_bytes @@ -106,6 +107,16 @@ huge pages although processes will also directly compact memory as required. ============================================================== +compact_unevictable_allowed + +Available only when CONFIG_COMPACTION is set. When set to 1, compaction is +allowed to examine the unevictable lru (mlocked pages) for pages to compact. +This should be used on systems where stalls for minor page faults are an +acceptable trade for large contiguous free memory. Set to 0 to prevent +compaction from moving pages that are unevictable. Default value is 1. + +============================================================== + dirty_background_bytes Contains the amount of dirty memory at which the background kernel diff --git a/include/linux/compaction.h b/include/linux/compaction.h index a014559e4a49..aa8f61cf3a19 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -34,6 +34,7 @@ extern int sysctl_compaction_handler(struct ctl_table *table, int write, extern int sysctl_extfrag_threshold; extern int sysctl_extfrag_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos); +extern int sysctl_compact_unevictable_allowed; extern int fragmentation_index(struct zone *zone, unsigned int order); extern unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order, diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 8c0eabd41886..42b7fc2860c1 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1335,6 +1335,15 @@ static struct ctl_table vm_table[] = { .extra1 = &min_extfrag_threshold, .extra2 = &max_extfrag_threshold, }, + { + .procname = "compact_unevictable_allowed", + .data = &sysctl_compact_unevictable_allowed, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + .extra1 = &zero, + .extra2 = &one, + }, #endif /* CONFIG_COMPACTION */ { diff --git a/mm/compaction.c b/mm/compaction.c index a18201a8124e..570426edcadf 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1047,6 +1047,12 @@ typedef enum { } isolate_migrate_t; /* + * Allow userspace to control policy on scanning the unevictable LRU for + * compactable pages. + */ +int sysctl_compact_unevictable_allowed __read_mostly = 1; + +/* * Isolate all pages that can be migrated from the first suitable block, * starting at the block pointed to by the migrate scanner pfn within * compact_control. @@ -1057,6 +1063,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, unsigned long low_pfn, end_pfn; struct page *page; const isolate_mode_t isolate_mode = + (sysctl_compact_unevictable_allowed ? ISOLATE_UNEVICTABLE : 0) | (cc->mode == MIGRATE_ASYNC ? ISOLATE_ASYNC_MIGRATE : 0); /* |