Commit 16aca2c9 authored by Yosry Ahmed's avatar Yosry Ahmed Committed by Andrew Morton
Browse files

mm: restore per-memcg proactive reclaim with !CONFIG_NUMA 

Commit 2b7226af ("mm/memcg: make memory.reclaim interface generic")
moved proactive reclaim logic from memory.reclaim handler to a generic
user_proactive_reclaim() helper to be used for per-node proactive reclaim.

However, user_proactive_reclaim() was only defined under CONFIG_NUMA, with
a stub always returning 0 otherwise.  This broke memory.reclaim on
!CONFIG_NUMA configs, causing it to report success without actually
attempting reclaim.

Move the definition of user_proactive_reclaim() outside CONFIG_NUMA, and
instead define a stub for __node_reclaim() in the !CONFIG_NUMA case. 
__node_reclaim() is only called from user_proactive_reclaim() when a write
is made to sys/devices/system/node/nodeX/reclaim, which is only defined
with CONFIG_NUMA.

Link: https://lkml.kernel.org/r/20260116205247.928004-1-yosry.ahmed@linux.dev


Fixes: 2b7226af ("mm/memcg: make memory.reclaim interface generic")
Signed-off-by: default avatarYosry Ahmed <yosry.ahmed@linux.dev>
Acked-by: default avatarShakeel Butt <shakeel.butt@linux.dev>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9bc9ccbf

mm/internal.h

+0 −8
Original line number Diff line number Diff line
@@ -538,16 +538,8 @@ extern unsigned long highest_memmap_pfn; 
bool folio_isolate_lru(struct folio *folio);

void folio_putback_lru(struct folio *folio);

extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason);

#ifdef CONFIG_NUMA

int user_proactive_reclaim(char *buf,

			   struct mem_cgroup *memcg, pg_data_t *pgdat);

#else

static inline int user_proactive_reclaim(char *buf,

			   struct mem_cgroup *memcg, pg_data_t *pgdat)

{

	return 0;

}

#endif



/*

 * in mm/rmap.c:

mm/vmscan.c

+11 −2
Original line number Diff line number Diff line
@@ -7707,6 +7707,17 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order) 
	return ret;

}



#else



static unsigned long __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask,

				    unsigned long nr_pages,

				    struct scan_control *sc)

{

	return 0;

}



#endif



enum {

	MEMORY_RECLAIM_SWAPPINESS = 0,

	MEMORY_RECLAIM_SWAPPINESS_MAX,
@@ -7814,8 +7825,6 @@ int user_proactive_reclaim(char *buf, 
	return 0;

}



#endif



/**

 * check_move_unevictable_folios - Move evictable folios to appropriate zone

 * lru list