The deferred split THPs may get accumulated with some workloads, they would get shrunk when memory pressure is hit. Now we use DEFAULT_SEEKS to determine how many objects would get scanned then split if possible, but actually they are not like other system cache objects, i.e. inode cache which would incur extra I/O if over reclaimed, the unmapped pages will not be accessed anymore, so we could shrink them more aggressively.
We could shrink THPs more pro-actively even though memory pressure is not hit, however, IMHO waiting for memory pressure is still a good compromise and trade-off. And, we do have simpler ways to shrink these objects harder until we have to take other means do pro-actively drain. Change shrinker->seeks to 0 to shrink deferred split THPs harder. Cc: Kirill A. Shutemov <[email protected]> Cc: Kirill Tkhai <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Shakeel Butt <[email protected]> Cc: David Rientjes <[email protected]> Signed-off-by: Yang Shi <[email protected]> --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 3b78910..1d6b1f1 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2955,7 +2955,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, static struct shrinker deferred_split_shrinker = { .count_objects = deferred_split_count, .scan_objects = deferred_split_scan, - .seeks = DEFAULT_SEEKS, + .seeks = 0, .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | SHRINKER_NONSLAB, }; -- 1.8.3.1
