Commit 2b7226af authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Andrew Morton
Browse files

mm/memcg: make memory.reclaim interface generic 

This adds a general call for both parsing as well as the common reclaim
semantics.  memcg is still the only user and no change in semantics.

[akpm@linux-foundation.org: fix CONFIG_NUMA=n build]
Link: https://lkml.kernel.org/r/20250623185851.830632-3-dave@stgolabs.net


Signed-off-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Acked-by: default avatarShakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7a92f4f5

mm/internal.h

+10 −0
Original line number Diff line number Diff line
@@ -533,6 +533,16 @@ 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/memcontrol.c

+4 −73
Original line number Diff line number Diff line
@@ -51,7 +51,6 @@ 
#include <linux/spinlock.h>

#include <linux/fs.h>

#include <linux/seq_file.h>

#include <linux/parser.h>

#include <linux/vmpressure.h>

#include <linux/memremap.h>

#include <linux/mm_inline.h>
@@ -4564,83 +4563,15 @@ static ssize_t memory_oom_group_write(struct kernfs_open_file *of, 
	return nbytes;

}



enum {

	MEMORY_RECLAIM_SWAPPINESS = 0,

	MEMORY_RECLAIM_SWAPPINESS_MAX,

	MEMORY_RECLAIM_NULL,

};



static const match_table_t tokens = {

	{ MEMORY_RECLAIM_SWAPPINESS, "swappiness=%d"},

	{ MEMORY_RECLAIM_SWAPPINESS_MAX, "swappiness=max"},

	{ MEMORY_RECLAIM_NULL, NULL },

};



static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,

			      size_t nbytes, loff_t off)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));

	unsigned int nr_retries = MAX_RECLAIM_RETRIES;

	unsigned long nr_to_reclaim, nr_reclaimed = 0;

	int swappiness = -1;

	unsigned int reclaim_options;

	char *old_buf, *start;

	substring_t args[MAX_OPT_ARGS];



	buf = strstrip(buf);



	old_buf = buf;

	nr_to_reclaim = memparse(buf, &buf) / PAGE_SIZE;

	if (buf == old_buf)

		return -EINVAL;



	buf = strstrip(buf);



	while ((start = strsep(&buf, " ")) != NULL) {

		if (!strlen(start))

			continue;

		switch (match_token(start, tokens, args)) {

		case MEMORY_RECLAIM_SWAPPINESS:

			if (match_int(&args[0], &swappiness))

				return -EINVAL;

			if (swappiness < MIN_SWAPPINESS || swappiness > MAX_SWAPPINESS)

				return -EINVAL;

			break;

		case MEMORY_RECLAIM_SWAPPINESS_MAX:

			swappiness = SWAPPINESS_ANON_ONLY;

			break;

		default:

			return -EINVAL;

		}

	}



	reclaim_options	= MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE;

	while (nr_reclaimed < nr_to_reclaim) {

		/* Will converge on zero, but reclaim enforces a minimum */

		unsigned long batch_size = (nr_to_reclaim - nr_reclaimed) / 4;

		unsigned long reclaimed;



		if (signal_pending(current))

			return -EINTR;



		/*

		 * This is the final attempt, drain percpu lru caches in the

		 * hope of introducing more evictable pages for

		 * try_to_free_mem_cgroup_pages().

		 */

		if (!nr_retries)

			lru_add_drain_all();



		reclaimed = try_to_free_mem_cgroup_pages(memcg,

					batch_size, GFP_KERNEL,

					reclaim_options,

					swappiness == -1 ? NULL : &swappiness);



		if (!reclaimed && !nr_retries--)

			return -EAGAIN;

	int ret;



		nr_reclaimed += reclaimed;

	}

	ret = user_proactive_reclaim(buf, memcg, NULL);

	if (ret)

		return ret;



	return nbytes;

}

mm/vmscan.c

+98 −0
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ 
#include <linux/rculist_nulls.h>

#include <linux/random.h>

#include <linux/mmu_notifier.h>

#include <linux/parser.h>



#include <asm/tlbflush.h>

#include <asm/div64.h>
@@ -6714,6 +6715,15 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 


	return nr_reclaimed;

}

#else

unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,

					   unsigned long nr_pages,

					   gfp_t gfp_mask,

					   unsigned int reclaim_options,

					   int *swappiness)

{

	return 0;

}

#endif



static void kswapd_age_node(struct pglist_data *pgdat, struct scan_control *sc)
@@ -7708,6 +7718,94 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order) 


	return ret;

}



enum {

	MEMORY_RECLAIM_SWAPPINESS = 0,

	MEMORY_RECLAIM_SWAPPINESS_MAX,

	MEMORY_RECLAIM_NULL,

};

static const match_table_t tokens = {

	{ MEMORY_RECLAIM_SWAPPINESS, "swappiness=%d"},

	{ MEMORY_RECLAIM_SWAPPINESS_MAX, "swappiness=max"},

	{ MEMORY_RECLAIM_NULL, NULL },

};



int user_proactive_reclaim(char *buf, struct mem_cgroup *memcg, pg_data_t *pgdat)

{

	unsigned int nr_retries = MAX_RECLAIM_RETRIES;

	unsigned long nr_to_reclaim, nr_reclaimed = 0;

	int swappiness = -1;

	char *old_buf, *start;

	substring_t args[MAX_OPT_ARGS];



	if (!buf || (!memcg && !pgdat))

		return -EINVAL;



	buf = strstrip(buf);



	old_buf = buf;

	nr_to_reclaim = memparse(buf, &buf) / PAGE_SIZE;

	if (buf == old_buf)

		return -EINVAL;



	buf = strstrip(buf);



	while ((start = strsep(&buf, " ")) != NULL) {

		if (!strlen(start))

			continue;

		switch (match_token(start, tokens, args)) {

		case MEMORY_RECLAIM_SWAPPINESS:

			if (match_int(&args[0], &swappiness))

				return -EINVAL;

			if (swappiness < MIN_SWAPPINESS ||

			    swappiness > MAX_SWAPPINESS)

				return -EINVAL;

			break;

		case MEMORY_RECLAIM_SWAPPINESS_MAX:

			swappiness = SWAPPINESS_ANON_ONLY;

			break;

		default:

			return -EINVAL;

		}

	}



	while (nr_reclaimed < nr_to_reclaim) {

		/* Will converge on zero, but reclaim enforces a minimum */

		unsigned long batch_size = (nr_to_reclaim - nr_reclaimed) / 4;

		unsigned long reclaimed;



		if (signal_pending(current))

			return -EINTR;



		/*

		 * This is the final attempt, drain percpu lru caches in the

		 * hope of introducing more evictable pages.

		 */

		if (!nr_retries)

			lru_add_drain_all();



		if (memcg) {

			unsigned int reclaim_options;



			reclaim_options = MEMCG_RECLAIM_MAY_SWAP |

					  MEMCG_RECLAIM_PROACTIVE;

			reclaimed = try_to_free_mem_cgroup_pages(memcg,

						 batch_size, GFP_KERNEL,

						 reclaim_options,

						 swappiness == -1 ? NULL : &swappiness);

		} else {

			return -EINVAL;

		}



		if (!reclaimed && !nr_retries--)

			return -EAGAIN;



		nr_reclaimed += reclaimed;

	}



	return 0;

}



#endif



/**