Commit 0f6acee1 authored by Liu Shixin's avatar Liu Shixin
Browse files

memcg: add page type to memory.reclaim interface 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7CGGT


CVE: NA

--------------------------------

Add anon/file to memory.reclaim interface to limit only reclaim one type
pages. The lru algorithm can reclaim cold pages and balance between file
and anon. But it didn't consider the speed of backend device. For example,
if there is zram device, reclaim anon pages might has less impact on
performance. So extend memory.reclaim interface to reclaim one type pages.
Usage:
	"echo <size> type=anon > memory.reclaim"
	"echo <size> type=file > memory.reclaim"

Also compatible with the previous format.

Signed-off-by: default avatarLiu Shixin <liushixin2@huawei.com>
parent 789303ae

Documentation/admin-guide/cgroup-v2.rst

+5 −4
Original line number Diff line number Diff line
@@ -1196,15 +1196,16 @@ PAGE_SIZE multiple when read back. 
	target cgroup.



	This file accepts a single key, the number of bytes to reclaim.

	No nested keys are currently supported.



	Example::



	  echo "1G" > memory.reclaim



	The interface can be later extended with nested keys to

	configure the reclaim behavior. For example, specify the

	type of memory to reclaim from (anon, file, ..).

	This file also accepts nested keys, the number of bytes to reclaim

	with the type of memory to reclaim.



	Example::

	  echo "1G type=file" > memory.reclaim



	Please note that the kernel can over or under reclaim from

	the target cgroup. If less bytes are reclaimed than the

include/linux/swap.h

+1 −0
Original line number Diff line number Diff line
@@ -379,6 +379,7 @@ extern int __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode); 


#define MEMCG_RECLAIM_MAY_SWAP (1 << 1)

#define MEMCG_RECLAIM_PROACTIVE (1 << 2)

#define MEMCG_RECLAIM_NOT_FILE (1 << 3)

extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,

						  unsigned long nr_pages,

						  gfp_t gfp_mask,

mm/memcontrol.c

+36 −2
Original line number Diff line number Diff line
@@ -5266,6 +5266,35 @@ static int memcg_events_local_show(struct seq_file *m, void *v) 
	return 0;

}



static int reclaim_param_parse(char *buf, unsigned long *nr_pages,

			       unsigned int *reclaim_options)

{

	char *endp;

	u64 bytes;



	if (!strcmp(buf, "")) {

		*nr_pages = PAGE_COUNTER_MAX;

		return 0;

	}



	bytes = memparse(buf, &endp);

	if (*endp == ' ') {

		buf = endp + 1;

		buf = strim(buf);

		if (!strcmp(buf, "type=anon"))

			*reclaim_options |= MEMCG_RECLAIM_NOT_FILE;

		else if (!strcmp(buf, "type=file"))

			*reclaim_options &= ~MEMCG_RECLAIM_MAY_SWAP;

		else

			return -EINVAL;

	} else if (*endp != '\0')

		return -EINVAL;



	*nr_pages = min(bytes / PAGE_SIZE, (u64)PAGE_COUNTER_MAX);



	return 0;

}



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

			      size_t nbytes, loff_t off)

{
@@ -5275,8 +5304,9 @@ static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf, 
	unsigned int reclaim_options;

	int err;



	reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE;

	buf = strstrip(buf);

	err = page_counter_memparse(buf, "", &nr_to_reclaim);

	err = reclaim_param_parse(buf, &nr_to_reclaim, &reclaim_options);

	if (err)

		return err;
@@ -5284,13 +5314,17 @@ static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf, 
			mem_cgroup_is_root(memcg))

		return -EINVAL;



	reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE;

	while (nr_reclaimed < nr_to_reclaim) {

		unsigned long reclaimed;



		if (signal_pending(current))

			return -EINTR;



		/* If only reclaim swap pages, check swap space at first. */

		if ((reclaim_options & MEMCG_RECLAIM_NOT_FILE) &&

		    (mem_cgroup_get_nr_swap_pages(memcg) <= 0))

			return -EAGAIN;



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

		 * hope of introducing more evictable pages for

		 * try_to_free_mem_cgroup_pages().

mm/vmscan.c

+9 −0
Original line number Diff line number Diff line
@@ -103,6 +103,9 @@ struct scan_control { 
	/* Can pages be swapped as part of reclaim? */

	unsigned int may_swap:1;



	/* Should skip file pages? */

	unsigned int not_file:1;



	/* Proactive reclaim invoked by userspace through memory.reclaim */

	unsigned int proactive:1;
@@ -2464,6 +2467,11 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, 
	unsigned long ap, fp;

	enum lru_list lru;



	if (sc->not_file) {

		scan_balance = SCAN_ANON;

		goto out;

	}



	/* If we have no swap space, do not bother scanning anon pages. */

	if (!sc->may_swap || mem_cgroup_get_nr_swap_pages(memcg) <= 0) {

		scan_balance = SCAN_FILE;
@@ -3583,6 +3591,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, 
		.may_unmap = 1,

		.may_swap = !!(reclaim_options & MEMCG_RECLAIM_MAY_SWAP),

		.proactive = !!(reclaim_options & MEMCG_RECLAIM_PROACTIVE),

		.not_file = !!(reclaim_options & MEMCG_RECLAIM_NOT_FILE),

	};

	/*

	 * Traverse the ZONELIST_FALLBACK zonelist of the current node to put