Commit 7679ba6b authored by Uladzislau Rezki (Sony)'s avatar Uladzislau Rezki (Sony) Committed by Andrew Morton
Browse files

mm: vmalloc: add a shrinker to drain vmap pools 

The added shrinker is used to return back current cached VAs into a global
vmap space, when a system enters into a low memory mode.

Link: https://lkml.kernel.org/r/20240102184633.748113-12-urezki@gmail.com


Signed-off-by: default avatarUladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Kazuhito Hagio <k-hagio-ab@nec.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8f33a2ff

mm/vmalloc.c

+39 −0
Original line number Diff line number Diff line
@@ -4917,8 +4917,37 @@ static void vmap_init_nodes(void) 
	}

}



static unsigned long

vmap_node_shrink_count(struct shrinker *shrink, struct shrink_control *sc)

{

	unsigned long count;

	struct vmap_node *vn;

	int i, j;



	for (count = 0, i = 0; i < nr_vmap_nodes; i++) {

		vn = &vmap_nodes[i];



		for (j = 0; j < MAX_VA_SIZE_PAGES; j++)

			count += READ_ONCE(vn->pool[j].len);

	}



	return count ? count : SHRINK_EMPTY;

}



static unsigned long

vmap_node_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)

{

	int i;



	for (i = 0; i < nr_vmap_nodes; i++)

		decay_va_pool_node(&vmap_nodes[i], true);



	return SHRINK_STOP;

}



void __init vmalloc_init(void)

{

	struct shrinker *vmap_node_shrinker;

	struct vmap_area *va;

	struct vmap_node *vn;

	struct vm_struct *tmp;
@@ -4966,4 +4995,14 @@ void __init vmalloc_init(void) 
	 */

	vmap_init_free_space();

	vmap_initialized = true;



	vmap_node_shrinker = shrinker_alloc(0, "vmap-node");

	if (!vmap_node_shrinker) {

		pr_err("Failed to allocate vmap-node shrinker!\n");

		return;

	}



	vmap_node_shrinker->count_objects = vmap_node_shrink_count;

	vmap_node_shrinker->scan_objects = vmap_node_shrink_scan;

	shrinker_register(vmap_node_shrinker);

}