Allow proactive reclaimers to submit an additional swappiness=<val>
argument to memory.reclaim. This overrides the global or per-memcg
swappiness setting for that reclaim attempt.
For example:
echo "2M swappiness=0" > /sys/fs/cgroup/memory.reclaim
will perform reclaim on the rootcg with a swappiness setting of 0 (no
swap) regardless of the vm.swappiness sysctl setting.
Signed-off-by: Dan Schatzberg <schatzberg.dan@xxxxxxxxx>
---
Documentation/admin-guide/cgroup-v2.rst | 19 +++++---
include/linux/swap.h | 3 +-
mm/memcontrol.c | 61 ++++++++++++++++++++-----
mm/vmscan.c | 11 +++--
4 files changed, 72 insertions(+), 22 deletions(-)
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 3f85254f3cef..06319349c072 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1282,17 +1282,10 @@ PAGE_SIZE multiple when read back.
This is a simple interface to trigger memory reclaim in the
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, ..).
-
Please note that the kernel can over or under reclaim from
the target cgroup. If less bytes are reclaimed than the
specified amount, -EAGAIN is returned.
@@ -1304,6 +1297,18 @@ PAGE_SIZE multiple when read back.
This means that the networking layer will not adapt based on
reclaim induced by memory.reclaim.
+The following nested keys are defined.
+
+ ========== ================================
+ swappiness Swappiness value to reclaim with
+ ========== ================================
+
+ Specifying a swappiness value instructs the kernel to perform
+ the reclaim with that swappiness value. Note that this has the
+ same semantics as the vm.swappiness sysctl - it sets the
+ relative IO cost of reclaiming anon vs file memory but does
+ not allow for reclaiming specific amounts of anon or file memory.
+
memory.peak
A read-only single value file which exists on non-root
cgroups.
diff --git a/include/linux/swap.h b/include/linux/swap.h
index e2ab76c25b4a..690898c347de 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -412,7 +412,8 @@ extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
unsigned long nr_pages,
gfp_t gfp_mask,
- unsigned int reclaim_options);
+ unsigned int reclaim_options,
+ int swappiness);
extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
gfp_t gfp_mask, bool noswap,
pg_data_t *pgdat,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9748a6b88bb8..be3d5797d9df 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -63,6 +63,7 @@
#include <linux/resume_user_mode.h>
#include <linux/psi.h>
#include <linux/seq_buf.h>
+#include <linux/parser.h>
#include <linux/sched/isolation.h>
#include "internal.h"
#include <net/sock.h>
@@ -2449,7 +2450,8 @@ static unsigned long reclaim_high(struct mem_cgroup *memcg,
psi_memstall_enter(&pflags);
nr_reclaimed += try_to_free_mem_cgroup_pages(memcg, nr_pages,
gfp_mask,
- MEMCG_RECLAIM_MAY_SWAP);
+ MEMCG_RECLAIM_MAY_SWAP,
+ mem_cgroup_swappiness(memcg));
psi_memstall_leave(&pflags);
} while ((memcg = parent_mem_cgroup(memcg)) &&
!mem_cgroup_is_root(memcg));
@@ -2740,7 +2742,8 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
psi_memstall_enter(&pflags);
nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
- gfp_mask, reclaim_options);
+ gfp_mask, reclaim_options,
+ mem_cgroup_swappiness(memcg));
psi_memstall_leave(&pflags);
if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
@@ -3660,7 +3663,8 @@ static int mem_cgroup_resize_max(struct mem_cgroup *memcg,
}
if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
- memsw ? 0 : MEMCG_RECLAIM_MAY_SWAP)) {
+ memsw ? 0 : MEMCG_RECLAIM_MAY_SWAP,
+ mem_cgroup_swappiness(memcg))) {
ret = -EBUSY;
break;
}
@@ -3774,7 +3778,8 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
return -EINTR;
if (!try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
- MEMCG_RECLAIM_MAY_SWAP))
+ MEMCG_RECLAIM_MAY_SWAP,
+ mem_cgroup_swappiness(memcg)))
nr_retries--;
}
@@ -6720,7 +6725,8 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
}
reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
- GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP);
+ GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP,
+ mem_cgroup_swappiness(memcg));
if (!reclaimed && !nr_retries--)
break;
@@ -6769,7 +6775,8 @@ static ssize_t memory_max_write(struct kernfs_open_file *of,
if (nr_reclaims) {
if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
- GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP))
+ GFP_KERNEL, MEMCG_RECLAIM_MAY_SWAP,
+ mem_cgroup_swappiness(memcg)))
nr_reclaims--;
continue;
}
@@ -6895,6 +6902,16 @@ static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
return nbytes;
}
+enum {
+ MEMORY_RECLAIM_SWAPPINESS = 0,
+ MEMORY_RECLAIM_NULL,
+};
+
+static const match_table_t tokens = {
+ { MEMORY_RECLAIM_SWAPPINESS, "swappiness=%d"},
+ { MEMORY_RECLAIM_NULL, NULL },
+};
+
static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
size_t nbytes, loff_t off)
{
@@ -6902,12 +6919,33 @@ static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
unsigned int nr_retries = MAX_RECLAIM_RETRIES;
unsigned long nr_to_reclaim, nr_reclaimed = 0;
unsigned int reclaim_options;
- int err;
+ char *old_buf, *start;
+ substring_t args[MAX_OPT_ARGS];
+ int swappiness = mem_cgroup_swappiness(memcg);
buf = strstrip(buf);
- err = page_counter_memparse(buf, "", &nr_to_reclaim);
- if (err)
- return err;
+
+ 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;
+ default:
+ return -EINVAL;
+ }
+ }
reclaim_options = MEMCG_RECLAIM_MAY_SWAP | MEMCG_RECLAIM_PROACTIVE;
while (nr_reclaimed < nr_to_reclaim) {
@@ -6926,7 +6964,8 @@ static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
reclaimed = try_to_free_mem_cgroup_pages(memcg,
min(nr_to_reclaim - nr_reclaimed, SWAP_CLUSTER_MAX),
- GFP_KERNEL, reclaim_options);
+ GFP_KERNEL, reclaim_options,
+ swappiness);
if (!reclaimed && !nr_retries--)
return -EAGAIN;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2aa671fe938b..cfef06c7c23f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -136,6 +136,9 @@ struct scan_control {
/* Always discard instead of demoting to lower tier memory */
unsigned int no_demotion:1;
+ /* Swappiness value for reclaim */
+ int swappiness;
+
/* Allocation order */
s8 order;
@@ -2327,7 +2330,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
struct pglist_data *pgdat = lruvec_pgdat(lruvec);
struct mem_cgroup *memcg = lruvec_memcg(lruvec);
unsigned long anon_cost, file_cost, total_cost;
- int swappiness = mem_cgroup_swappiness(memcg);
+ int swappiness = sc->swappiness;
u64 fraction[ANON_AND_FILE];
u64 denominator = 0; /* gcc */
enum scan_balance scan_balance;
@@ -2608,7 +2611,7 @@ static int get_swappiness(struct lruvec *lruvec, struct scan_control *sc)
mem_cgroup_get_nr_swap_pages(memcg) < MIN_LRU_BATCH)
return 0;
- return mem_cgroup_swappiness(memcg);
+ return sc->swappiness;
}
static int get_nr_gens(struct lruvec *lruvec, int type)
@@ -6433,7 +6436,8 @@ unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
unsigned long nr_pages,
gfp_t gfp_mask,
- unsigned int reclaim_options)
+ unsigned int reclaim_options,
+ int swappiness)
{
unsigned long nr_reclaimed;
unsigned int noreclaim_flag;
@@ -6448,6 +6452,7 @@ 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),
+ .swappiness = swappiness,
};
/*
* Traverse the ZONELIST_FALLBACK zonelist of the current node to put
--
2.34.1
