| Message ID | 154109387197.925352.10499549042420271600.stgit@buzz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC] mm: do not start node_reclaim for page order > MAX_ORDER | expand |
On Thu 01-11-18 20:37:52, Konstantin Khlebnikov wrote: > Page allocator has check in __alloc_pages_slowpath() but nowdays > there is earlier entry point into reclimer without such check: > get_page_from_freelist() -> node_reclaim(). Is the order check so expensive that it would be visible in the fast path? Spreading these MAX_ORDER checks sounds quite fragile to me. > Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> > --- > mm/vmscan.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 62ac0c488624..52f672420f0b 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -4117,6 +4117,12 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order) > { > int ret; > > + /* > + * Do not scan if allocation will never succeed. > + */ > + if (order >= MAX_ORDER) > + return NODE_RECLAIM_NOSCAN; > + > /* > * Node reclaim reclaims unmapped file backed pages and > * slab pages if we are over the defined limits. >
diff --git a/mm/vmscan.c b/mm/vmscan.c index 62ac0c488624..52f672420f0b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4117,6 +4117,12 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order) { int ret; + /* + * Do not scan if allocation will never succeed. + */ + if (order >= MAX_ORDER) + return NODE_RECLAIM_NOSCAN; + /* * Node reclaim reclaims unmapped file backed pages and * slab pages if we are over the defined limits.
Page allocator has check in __alloc_pages_slowpath() but nowdays there is earlier entry point into reclimer without such check: get_page_from_freelist() -> node_reclaim(). Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> --- mm/vmscan.c | 6 ++++++ 1 file changed, 6 insertions(+)