The quilt patch titled
Subject: mm: memcg: move soft limit reclaim code to memcontrol-v1.c
has been removed from the -mm tree. Its filename was
mm-memcg-move-soft-limit-reclaim-code-to-memcontrol-v1c.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Subject: mm: memcg: move soft limit reclaim code to memcontrol-v1.c
Date: Mon, 24 Jun 2024 17:58:54 -0700
Soft limits are cgroup v1-specific and are not supported by cgroup v2, so
let's move the corresponding code into memcontrol-v1.c.
Aside from simple moving the code, this commits introduces a trivial
memcg1_soft_limit_reset() function to reset soft limits and also moves the
global soft limit tree initialization code into a new memcg1_init()
function.
It also moves corresponding declarations shared between memcontrol.c and
memcontrol-v1.c into mm/memcontrol-v1.h.
Link: https://lkml.kernel.org/r/20240625005906.106920-3-roman.gushchin@xxxxxxxxx
Signed-off-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol-v1.c | 342 +++++++++++++++++++++++++++++++++++++++++++
mm/memcontrol-v1.h | 7
mm/memcontrol.c | 337 ------------------------------------------
3 files changed, 353 insertions(+), 333 deletions(-)
--- a/mm/memcontrol.c~mm-memcg-move-soft-limit-reclaim-code-to-memcontrol-v1c
+++ a/mm/memcontrol.c
@@ -71,6 +71,7 @@
#include <net/ip.h>
#include "slab.h"
#include "swap.h"
+#include "memcontrol-v1.h"
#include <linux/uaccess.h>
@@ -107,23 +108,6 @@ static bool do_memsw_account(void)
#define THRESHOLDS_EVENTS_TARGET 128
#define SOFTLIMIT_EVENTS_TARGET 1024
-/*
- * Cgroups above their limits are maintained in a RB-Tree, independent of
- * their hierarchy representation
- */
-
-struct mem_cgroup_tree_per_node {
- struct rb_root rb_root;
- struct rb_node *rb_rightmost;
- spinlock_t lock;
-};
-
-struct mem_cgroup_tree {
- struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
-};
-
-static struct mem_cgroup_tree soft_limit_tree __read_mostly;
-
/* for OOM */
struct mem_cgroup_eventfd_list {
struct list_head list;
@@ -198,13 +182,6 @@ static struct move_charge_struct {
.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
};
-/*
- * Maximum loops in mem_cgroup_soft_reclaim(), used for soft
- * limit reclaim to prevent infinite loops, if they ever occur.
- */
-#define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
-#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
-
/* for encoding cft->private value on file */
enum res_type {
_MEM,
@@ -412,169 +389,6 @@ ino_t page_cgroup_ino(struct page *page)
return ino;
}
-static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
- struct mem_cgroup_tree_per_node *mctz,
- unsigned long new_usage_in_excess)
-{
- struct rb_node **p = &mctz->rb_root.rb_node;
- struct rb_node *parent = NULL;
- struct mem_cgroup_per_node *mz_node;
- bool rightmost = true;
-
- if (mz->on_tree)
- return;
-
- mz->usage_in_excess = new_usage_in_excess;
- if (!mz->usage_in_excess)
- return;
- while (*p) {
- parent = *p;
- mz_node = rb_entry(parent, struct mem_cgroup_per_node,
- tree_node);
- if (mz->usage_in_excess < mz_node->usage_in_excess) {
- p = &(*p)->rb_left;
- rightmost = false;
- } else {
- p = &(*p)->rb_right;
- }
- }
-
- if (rightmost)
- mctz->rb_rightmost = &mz->tree_node;
-
- rb_link_node(&mz->tree_node, parent, p);
- rb_insert_color(&mz->tree_node, &mctz->rb_root);
- mz->on_tree = true;
-}
-
-static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
- struct mem_cgroup_tree_per_node *mctz)
-{
- if (!mz->on_tree)
- return;
-
- if (&mz->tree_node == mctz->rb_rightmost)
- mctz->rb_rightmost = rb_prev(&mz->tree_node);
-
- rb_erase(&mz->tree_node, &mctz->rb_root);
- mz->on_tree = false;
-}
-
-static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
- struct mem_cgroup_tree_per_node *mctz)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&mctz->lock, flags);
- __mem_cgroup_remove_exceeded(mz, mctz);
- spin_unlock_irqrestore(&mctz->lock, flags);
-}
-
-static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
-{
- unsigned long nr_pages = page_counter_read(&memcg->memory);
- unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
- unsigned long excess = 0;
-
- if (nr_pages > soft_limit)
- excess = nr_pages - soft_limit;
-
- return excess;
-}
-
-static void mem_cgroup_update_tree(struct mem_cgroup *memcg, int nid)
-{
- unsigned long excess;
- struct mem_cgroup_per_node *mz;
- struct mem_cgroup_tree_per_node *mctz;
-
- if (lru_gen_enabled()) {
- if (soft_limit_excess(memcg))
- lru_gen_soft_reclaim(memcg, nid);
- return;
- }
-
- mctz = soft_limit_tree.rb_tree_per_node[nid];
- if (!mctz)
- return;
- /*
- * Necessary to update all ancestors when hierarchy is used.
- * because their event counter is not touched.
- */
- for (; memcg; memcg = parent_mem_cgroup(memcg)) {
- mz = memcg->nodeinfo[nid];
- excess = soft_limit_excess(memcg);
- /*
- * We have to update the tree if mz is on RB-tree or
- * mem is over its softlimit.
- */
- if (excess || mz->on_tree) {
- unsigned long flags;
-
- spin_lock_irqsave(&mctz->lock, flags);
- /* if on-tree, remove it */
- if (mz->on_tree)
- __mem_cgroup_remove_exceeded(mz, mctz);
- /*
- * Insert again. mz->usage_in_excess will be updated.
- * If excess is 0, no tree ops.
- */
- __mem_cgroup_insert_exceeded(mz, mctz, excess);
- spin_unlock_irqrestore(&mctz->lock, flags);
- }
- }
-}
-
-static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
-{
- struct mem_cgroup_tree_per_node *mctz;
- struct mem_cgroup_per_node *mz;
- int nid;
-
- for_each_node(nid) {
- mz = memcg->nodeinfo[nid];
- mctz = soft_limit_tree.rb_tree_per_node[nid];
- if (mctz)
- mem_cgroup_remove_exceeded(mz, mctz);
- }
-}
-
-static struct mem_cgroup_per_node *
-__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
-{
- struct mem_cgroup_per_node *mz;
-
-retry:
- mz = NULL;
- if (!mctz->rb_rightmost)
- goto done; /* Nothing to reclaim from */
-
- mz = rb_entry(mctz->rb_rightmost,
- struct mem_cgroup_per_node, tree_node);
- /*
- * Remove the node now but someone else can add it back,
- * we will to add it back at the end of reclaim to its correct
- * position in the tree.
- */
- __mem_cgroup_remove_exceeded(mz, mctz);
- if (!soft_limit_excess(mz->memcg) ||
- !css_tryget(&mz->memcg->css))
- goto retry;
-done:
- return mz;
-}
-
-static struct mem_cgroup_per_node *
-mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
-{
- struct mem_cgroup_per_node *mz;
-
- spin_lock_irq(&mctz->lock);
- mz = __mem_cgroup_largest_soft_limit_node(mctz);
- spin_unlock_irq(&mctz->lock);
- return mz;
-}
-
/* Subset of node_stat_item for memcg stats */
static const unsigned int memcg_node_stat_items[] = {
NR_INACTIVE_ANON,
@@ -1979,56 +1793,6 @@ unlock:
return ret;
}
-static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
- pg_data_t *pgdat,
- gfp_t gfp_mask,
- unsigned long *total_scanned)
-{
- struct mem_cgroup *victim = NULL;
- int total = 0;
- int loop = 0;
- unsigned long excess;
- unsigned long nr_scanned;
- struct mem_cgroup_reclaim_cookie reclaim = {
- .pgdat = pgdat,
- };
-
- excess = soft_limit_excess(root_memcg);
-
- while (1) {
- victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
- if (!victim) {
- loop++;
- if (loop >= 2) {
- /*
- * If we have not been able to reclaim
- * anything, it might because there are
- * no reclaimable pages under this hierarchy
- */
- if (!total)
- break;
- /*
- * We want to do more targeted reclaim.
- * excess >> 2 is not to excessive so as to
- * reclaim too much, nor too less that we keep
- * coming back to reclaim from this cgroup
- */
- if (total >= (excess >> 2) ||
- (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
- break;
- }
- continue;
- }
- total += mem_cgroup_shrink_node(victim, gfp_mask, false,
- pgdat, &nr_scanned);
- *total_scanned += nr_scanned;
- if (!soft_limit_excess(root_memcg))
- break;
- }
- mem_cgroup_iter_break(root_memcg, victim);
- return total;
-}
-
#ifdef CONFIG_LOCKDEP
static struct lockdep_map memcg_oom_lock_dep_map = {
.name = "memcg_oom_lock",
@@ -3923,88 +3687,6 @@ static int mem_cgroup_resize_max(struct
return ret;
}
-unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
- gfp_t gfp_mask,
- unsigned long *total_scanned)
-{
- unsigned long nr_reclaimed = 0;
- struct mem_cgroup_per_node *mz, *next_mz = NULL;
- unsigned long reclaimed;
- int loop = 0;
- struct mem_cgroup_tree_per_node *mctz;
- unsigned long excess;
-
- if (lru_gen_enabled())
- return 0;
-
- if (order > 0)
- return 0;
-
- mctz = soft_limit_tree.rb_tree_per_node[pgdat->node_id];
-
- /*
- * Do not even bother to check the largest node if the root
- * is empty. Do it lockless to prevent lock bouncing. Races
- * are acceptable as soft limit is best effort anyway.
- */
- if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root))
- return 0;
-
- /*
- * This loop can run a while, specially if mem_cgroup's continuously
- * keep exceeding their soft limit and putting the system under
- * pressure
- */
- do {
- if (next_mz)
- mz = next_mz;
- else
- mz = mem_cgroup_largest_soft_limit_node(mctz);
- if (!mz)
- break;
-
- reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
- gfp_mask, total_scanned);
- nr_reclaimed += reclaimed;
- spin_lock_irq(&mctz->lock);
-
- /*
- * If we failed to reclaim anything from this memory cgroup
- * it is time to move on to the next cgroup
- */
- next_mz = NULL;
- if (!reclaimed)
- next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
-
- excess = soft_limit_excess(mz->memcg);
- /*
- * One school of thought says that we should not add
- * back the node to the tree if reclaim returns 0.
- * But our reclaim could return 0, simply because due
- * to priority we are exposing a smaller subset of
- * memory to reclaim from. Consider this as a longer
- * term TODO.
- */
- /* If excess == 0, no tree ops */
- __mem_cgroup_insert_exceeded(mz, mctz, excess);
- spin_unlock_irq(&mctz->lock);
- css_put(&mz->memcg->css);
- loop++;
- /*
- * Could not reclaim anything and there are no more
- * mem cgroups to try or we seem to be looping without
- * reclaiming anything.
- */
- if (!nr_reclaimed &&
- (next_mz == NULL ||
- loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
- break;
- } while (!nr_reclaimed);
- if (next_mz)
- css_put(&next_mz->memcg->css);
- return nr_reclaimed;
-}
-
/*
* Reclaims as many pages from the given memcg as possible.
*
@@ -5782,7 +5464,7 @@ mem_cgroup_css_alloc(struct cgroup_subsy
return ERR_CAST(memcg);
page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
- WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
+ memcg1_soft_limit_reset(memcg);
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
memcg->zswap_max = PAGE_COUNTER_MAX;
WRITE_ONCE(memcg->zswap_writeback,
@@ -5955,7 +5637,7 @@ static void mem_cgroup_css_reset(struct
page_counter_set_min(&memcg->memory, 0);
page_counter_set_low(&memcg->memory, 0);
page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
- WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
+ memcg1_soft_limit_reset(memcg);
page_counter_set_high(&memcg->swap, PAGE_COUNTER_MAX);
memcg_wb_domain_size_changed(memcg);
}
@@ -7950,7 +7632,7 @@ __setup("cgroup.memory=", cgroup_memory)
*/
static int __init mem_cgroup_init(void)
{
- int cpu, node;
+ int cpu;
/*
* Currently s32 type (can refer to struct batched_lruvec_stat) is
@@ -7967,17 +7649,6 @@ static int __init mem_cgroup_init(void)
INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
drain_local_stock);
- for_each_node(node) {
- struct mem_cgroup_tree_per_node *rtpn;
-
- rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node);
-
- rtpn->rb_root = RB_ROOT;
- rtpn->rb_rightmost = NULL;
- spin_lock_init(&rtpn->lock);
- soft_limit_tree.rb_tree_per_node[node] = rtpn;
- }
-
return 0;
}
subsys_initcall(mem_cgroup_init);
--- a/mm/memcontrol-v1.c~mm-memcg-move-soft-limit-reclaim-code-to-memcontrol-v1c
+++ a/mm/memcontrol-v1.c
@@ -1,3 +1,345 @@
// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/memcontrol.h>
+#include <linux/swap.h>
+#include <linux/mm_inline.h>
+
#include "memcontrol-v1.h"
+
+/*
+ * Cgroups above their limits are maintained in a RB-Tree, independent of
+ * their hierarchy representation
+ */
+
+struct mem_cgroup_tree_per_node {
+ struct rb_root rb_root;
+ struct rb_node *rb_rightmost;
+ spinlock_t lock;
+};
+
+struct mem_cgroup_tree {
+ struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
+};
+
+static struct mem_cgroup_tree soft_limit_tree __read_mostly;
+
+/*
+ * Maximum loops in mem_cgroup_soft_reclaim(), used for soft
+ * limit reclaim to prevent infinite loops, if they ever occur.
+ */
+#define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
+#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
+
+static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz,
+ unsigned long new_usage_in_excess)
+{
+ struct rb_node **p = &mctz->rb_root.rb_node;
+ struct rb_node *parent = NULL;
+ struct mem_cgroup_per_node *mz_node;
+ bool rightmost = true;
+
+ if (mz->on_tree)
+ return;
+
+ mz->usage_in_excess = new_usage_in_excess;
+ if (!mz->usage_in_excess)
+ return;
+ while (*p) {
+ parent = *p;
+ mz_node = rb_entry(parent, struct mem_cgroup_per_node,
+ tree_node);
+ if (mz->usage_in_excess < mz_node->usage_in_excess) {
+ p = &(*p)->rb_left;
+ rightmost = false;
+ } else {
+ p = &(*p)->rb_right;
+ }
+ }
+
+ if (rightmost)
+ mctz->rb_rightmost = &mz->tree_node;
+
+ rb_link_node(&mz->tree_node, parent, p);
+ rb_insert_color(&mz->tree_node, &mctz->rb_root);
+ mz->on_tree = true;
+}
+
+static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz)
+{
+ if (!mz->on_tree)
+ return;
+
+ if (&mz->tree_node == mctz->rb_rightmost)
+ mctz->rb_rightmost = rb_prev(&mz->tree_node);
+
+ rb_erase(&mz->tree_node, &mctz->rb_root);
+ mz->on_tree = false;
+}
+
+static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
+ struct mem_cgroup_tree_per_node *mctz)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&mctz->lock, flags);
+ __mem_cgroup_remove_exceeded(mz, mctz);
+ spin_unlock_irqrestore(&mctz->lock, flags);
+}
+
+static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
+{
+ unsigned long nr_pages = page_counter_read(&memcg->memory);
+ unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
+ unsigned long excess = 0;
+
+ if (nr_pages > soft_limit)
+ excess = nr_pages - soft_limit;
+
+ return excess;
+}
+
+void mem_cgroup_update_tree(struct mem_cgroup *memcg, int nid)
+{
+ unsigned long excess;
+ struct mem_cgroup_per_node *mz;
+ struct mem_cgroup_tree_per_node *mctz;
+
+ if (lru_gen_enabled()) {
+ if (soft_limit_excess(memcg))
+ lru_gen_soft_reclaim(memcg, nid);
+ return;
+ }
+
+ mctz = soft_limit_tree.rb_tree_per_node[nid];
+ if (!mctz)
+ return;
+ /*
+ * Necessary to update all ancestors when hierarchy is used.
+ * because their event counter is not touched.
+ */
+ for (; memcg; memcg = parent_mem_cgroup(memcg)) {
+ mz = memcg->nodeinfo[nid];
+ excess = soft_limit_excess(memcg);
+ /*
+ * We have to update the tree if mz is on RB-tree or
+ * mem is over its softlimit.
+ */
+ if (excess || mz->on_tree) {
+ unsigned long flags;
+
+ spin_lock_irqsave(&mctz->lock, flags);
+ /* if on-tree, remove it */
+ if (mz->on_tree)
+ __mem_cgroup_remove_exceeded(mz, mctz);
+ /*
+ * Insert again. mz->usage_in_excess will be updated.
+ * If excess is 0, no tree ops.
+ */
+ __mem_cgroup_insert_exceeded(mz, mctz, excess);
+ spin_unlock_irqrestore(&mctz->lock, flags);
+ }
+ }
+}
+
+void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup_tree_per_node *mctz;
+ struct mem_cgroup_per_node *mz;
+ int nid;
+
+ for_each_node(nid) {
+ mz = memcg->nodeinfo[nid];
+ mctz = soft_limit_tree.rb_tree_per_node[nid];
+ if (mctz)
+ mem_cgroup_remove_exceeded(mz, mctz);
+ }
+}
+
+static struct mem_cgroup_per_node *
+__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
+{
+ struct mem_cgroup_per_node *mz;
+
+retry:
+ mz = NULL;
+ if (!mctz->rb_rightmost)
+ goto done; /* Nothing to reclaim from */
+
+ mz = rb_entry(mctz->rb_rightmost,
+ struct mem_cgroup_per_node, tree_node);
+ /*
+ * Remove the node now but someone else can add it back,
+ * we will to add it back at the end of reclaim to its correct
+ * position in the tree.
+ */
+ __mem_cgroup_remove_exceeded(mz, mctz);
+ if (!soft_limit_excess(mz->memcg) ||
+ !css_tryget(&mz->memcg->css))
+ goto retry;
+done:
+ return mz;
+}
+
+static struct mem_cgroup_per_node *
+mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
+{
+ struct mem_cgroup_per_node *mz;
+
+ spin_lock_irq(&mctz->lock);
+ mz = __mem_cgroup_largest_soft_limit_node(mctz);
+ spin_unlock_irq(&mctz->lock);
+ return mz;
+}
+
+static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
+ pg_data_t *pgdat,
+ gfp_t gfp_mask,
+ unsigned long *total_scanned)
+{
+ struct mem_cgroup *victim = NULL;
+ int total = 0;
+ int loop = 0;
+ unsigned long excess;
+ unsigned long nr_scanned;
+ struct mem_cgroup_reclaim_cookie reclaim = {
+ .pgdat = pgdat,
+ };
+
+ excess = soft_limit_excess(root_memcg);
+
+ while (1) {
+ victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
+ if (!victim) {
+ loop++;
+ if (loop >= 2) {
+ /*
+ * If we have not been able to reclaim
+ * anything, it might because there are
+ * no reclaimable pages under this hierarchy
+ */
+ if (!total)
+ break;
+ /*
+ * We want to do more targeted reclaim.
+ * excess >> 2 is not to excessive so as to
+ * reclaim too much, nor too less that we keep
+ * coming back to reclaim from this cgroup
+ */
+ if (total >= (excess >> 2) ||
+ (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
+ break;
+ }
+ continue;
+ }
+ total += mem_cgroup_shrink_node(victim, gfp_mask, false,
+ pgdat, &nr_scanned);
+ *total_scanned += nr_scanned;
+ if (!soft_limit_excess(root_memcg))
+ break;
+ }
+ mem_cgroup_iter_break(root_memcg, victim);
+ return total;
+}
+
+unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
+ gfp_t gfp_mask,
+ unsigned long *total_scanned)
+{
+ unsigned long nr_reclaimed = 0;
+ struct mem_cgroup_per_node *mz, *next_mz = NULL;
+ unsigned long reclaimed;
+ int loop = 0;
+ struct mem_cgroup_tree_per_node *mctz;
+ unsigned long excess;
+
+ if (lru_gen_enabled())
+ return 0;
+
+ if (order > 0)
+ return 0;
+
+ mctz = soft_limit_tree.rb_tree_per_node[pgdat->node_id];
+
+ /*
+ * Do not even bother to check the largest node if the root
+ * is empty. Do it lockless to prevent lock bouncing. Races
+ * are acceptable as soft limit is best effort anyway.
+ */
+ if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root))
+ return 0;
+
+ /*
+ * This loop can run a while, specially if mem_cgroup's continuously
+ * keep exceeding their soft limit and putting the system under
+ * pressure
+ */
+ do {
+ if (next_mz)
+ mz = next_mz;
+ else
+ mz = mem_cgroup_largest_soft_limit_node(mctz);
+ if (!mz)
+ break;
+
+ reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
+ gfp_mask, total_scanned);
+ nr_reclaimed += reclaimed;
+ spin_lock_irq(&mctz->lock);
+
+ /*
+ * If we failed to reclaim anything from this memory cgroup
+ * it is time to move on to the next cgroup
+ */
+ next_mz = NULL;
+ if (!reclaimed)
+ next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
+
+ excess = soft_limit_excess(mz->memcg);
+ /*
+ * One school of thought says that we should not add
+ * back the node to the tree if reclaim returns 0.
+ * But our reclaim could return 0, simply because due
+ * to priority we are exposing a smaller subset of
+ * memory to reclaim from. Consider this as a longer
+ * term TODO.
+ */
+ /* If excess == 0, no tree ops */
+ __mem_cgroup_insert_exceeded(mz, mctz, excess);
+ spin_unlock_irq(&mctz->lock);
+ css_put(&mz->memcg->css);
+ loop++;
+ /*
+ * Could not reclaim anything and there are no more
+ * mem cgroups to try or we seem to be looping without
+ * reclaiming anything.
+ */
+ if (!nr_reclaimed &&
+ (next_mz == NULL ||
+ loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
+ break;
+ } while (!nr_reclaimed);
+ if (next_mz)
+ css_put(&next_mz->memcg->css);
+ return nr_reclaimed;
+}
+
+static int __init memcg1_init(void)
+{
+ int node;
+
+ for_each_node(node) {
+ struct mem_cgroup_tree_per_node *rtpn;
+
+ rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node);
+
+ rtpn->rb_root = RB_ROOT;
+ rtpn->rb_rightmost = NULL;
+ spin_lock_init(&rtpn->lock);
+ soft_limit_tree.rb_tree_per_node[node] = rtpn;
+ }
+
+ return 0;
+}
+subsys_initcall(memcg1_init);
--- a/mm/memcontrol-v1.h~mm-memcg-move-soft-limit-reclaim-code-to-memcontrol-v1c
+++ a/mm/memcontrol-v1.h
@@ -3,5 +3,12 @@
#ifndef __MM_MEMCONTROL_V1_H
#define __MM_MEMCONTROL_V1_H
+void mem_cgroup_update_tree(struct mem_cgroup *memcg, int nid);
+void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg);
+
+static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg)
+{
+ WRITE_ONCE(memcg->soft_limit, PAGE_COUNTER_MAX);
+}
#endif /* __MM_MEMCONTROL_V1_H */
_
Patches currently in -mm which might be from roman.gushchin@xxxxxxxxx are
mm-memcg-drop-obsolete-cache-line-padding-in-struct-mem_cgroup.patch
mm-memcg-add-cache-line-padding-to-mem_cgroup_per_node.patch
