[patch 5/8] memcg: remove unused soft limit code

Johannes Weiner
2011-06-01T06:25:58Z

This should be merged into the previous patch, which is however better
readable and reviewable without all this deletion noise.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
include/linux/memcontrol.h | 9 -
include/linux/swap.h | 4 -
mm/memcontrol.c | 418 --------------------------------------------
mm/vmscan.c | 44 -----
4 files changed, 0 insertions(+), 475 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 7d99e87..cb02c00 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -150,8 +150,6 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
mem_cgroup_update_page_stat(page, idx, -1);
}

-unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
- gfp_t gfp_mask);
u64 mem_cgroup_get_limit(struct mem_cgroup *mem);

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -368,13 +366,6 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
}

static inline
-unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
- gfp_t gfp_mask)
-{
- return 0;
-}
-
-static inline
u64 mem_cgroup_get_limit(struct mem_cgroup *mem)
{
return 0;
diff --git a/include/linux/swap.h b/include/linux/swap.h
index a5c6da5..885cf19 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -254,10 +254,6 @@ extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
gfp_t gfp_mask, bool noswap,
unsigned int swappiness);
-extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
- gfp_t gfp_mask, bool noswap,
- unsigned int swappiness,
- struct zone *zone);
extern int __isolate_lru_page(struct page *page, int mode, int file);
extern unsigned long shrink_all_memory(unsigned long nr_pages);
extern int vm_swappiness;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 94f77cc3..78ae4dd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -34,7 +34,6 @@
#include <linux/rcupdate.h>
#include <linux/limits.h>
#include <linux/mutex.h>
-#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/swapops.h>
@@ -141,12 +140,6 @@ struct mem_cgroup_per_zone {
unsigned long count[NR_LRU_LISTS];

struct zone_reclaim_stat reclaim_stat;
- struct rb_node tree_node; /* RB tree node */
- unsigned long long usage_in_excess;/* Set to the value by which */
- /* the soft limit is exceeded*/
- bool on_tree;
- struct mem_cgroup *mem; /* Back pointer, we cannot */
- /* use container_of */
};
/* Macro for accessing counter */
#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
@@ -159,26 +152,6 @@ struct mem_cgroup_lru_info {
struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
};

-/*
- * Cgroups above their limits are maintained in a RB-Tree, independent of
- * their hierarchy representation
- */
-
-struct mem_cgroup_tree_per_zone {
- struct rb_root rb_root;
- spinlock_t lock;
-};
-
-struct mem_cgroup_tree_per_node {
- struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
-};
-
-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;
-
struct mem_cgroup_threshold {
struct eventfd_ctx *eventfd;
u64 threshold;
@@ -326,12 +299,7 @@ static bool move_file(void)
&mc.to->move_charge_at_immigrate);
}

-/*
- * Maximum loops in 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)

enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
@@ -388,164 +356,6 @@ page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
return mem_cgroup_zoneinfo(mem, nid, zid);
}

-static struct mem_cgroup_tree_per_zone *
-soft_limit_tree_node_zone(int nid, int zid)
-{
- return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
-}
-
-static struct mem_cgroup_tree_per_zone *
-soft_limit_tree_from_page(struct page *page)
-{
- int nid = page_to_nid(page);
- int zid = page_zonenum(page);
-
- return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
-}
-
-static void
-__mem_cgroup_insert_exceeded(struct mem_cgroup *mem,
- struct mem_cgroup_per_zone *mz,
- struct mem_cgroup_tree_per_zone *mctz,
- unsigned long long new_usage_in_excess)
-{
- struct rb_node **p = &mctz->rb_root.rb_node;
- struct rb_node *parent = NULL;
- struct mem_cgroup_per_zone *mz_node;
-
- 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_zone,
- tree_node);
- if (mz->usage_in_excess < mz_node->usage_in_excess)
- p = &(*p)->rb_left;
- /*
- * We can't avoid mem cgroups that are over their soft
- * limit by the same amount
- */
- else if (mz->usage_in_excess >= mz_node->usage_in_excess)
- p = &(*p)->rb_right;
- }
- 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 *mem,
- struct mem_cgroup_per_zone *mz,
- struct mem_cgroup_tree_per_zone *mctz)
-{
- if (!mz->on_tree)
- return;
- rb_erase(&mz->tree_node, &mctz->rb_root);
- mz->on_tree = false;
-}
-
-static void
-mem_cgroup_remove_exceeded(struct mem_cgroup *mem,
- struct mem_cgroup_per_zone *mz,
- struct mem_cgroup_tree_per_zone *mctz)
-{
- spin_lock(&mctz->lock);
- __mem_cgroup_remove_exceeded(mem, mz, mctz);
- spin_unlock(&mctz->lock);
-}
-
-
-static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
-{
- unsigned long long excess;
- struct mem_cgroup_per_zone *mz;
- struct mem_cgroup_tree_per_zone *mctz;
- int nid = page_to_nid(page);
- int zid = page_zonenum(page);
- mctz = soft_limit_tree_from_page(page);
-
- /*
- * Necessary to update all ancestors when hierarchy is used.
- * because their event counter is not touched.
- */
- for (; mem; mem = parent_mem_cgroup(mem)) {
- mz = mem_cgroup_zoneinfo(mem, nid, zid);
- excess = res_counter_soft_limit_excess(&mem->res);
- /*
- * We have to update the tree if mz is on RB-tree or
- * mem is over its softlimit.
- */
- if (excess || mz->on_tree) {
- spin_lock(&mctz->lock);
- /* if on-tree, remove it */
- if (mz->on_tree)
- __mem_cgroup_remove_exceeded(mem, mz, mctz);
- /*
- * Insert again. mz->usage_in_excess will be updated.
- * If excess is 0, no tree ops.
- */
- __mem_cgroup_insert_exceeded(mem, mz, mctz, excess);
- spin_unlock(&mctz->lock);
- }
- }
-}
-
-static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem)
-{
- int node, zone;
- struct mem_cgroup_per_zone *mz;
- struct mem_cgroup_tree_per_zone *mctz;
-
- for_each_node_state(node, N_POSSIBLE) {
- for (zone = 0; zone < MAX_NR_ZONES; zone++) {
- mz = mem_cgroup_zoneinfo(mem, node, zone);
- mctz = soft_limit_tree_node_zone(node, zone);
- mem_cgroup_remove_exceeded(mem, mz, mctz);
- }
- }
-}
-
-static struct mem_cgroup_per_zone *
-__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
-{
- struct rb_node *rightmost = NULL;
- struct mem_cgroup_per_zone *mz;
-
-retry:
- mz = NULL;
- rightmost = rb_last(&mctz->rb_root);
- if (!rightmost)
- goto done; /* Nothing to reclaim from */
-
- mz = rb_entry(rightmost, struct mem_cgroup_per_zone, 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->mem, mz, mctz);
- if (!res_counter_soft_limit_excess(&mz->mem->res) ||
- !css_tryget(&mz->mem->css))
- goto retry;
-done:
- return mz;
-}
-
-static struct mem_cgroup_per_zone *
-mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
-{
- struct mem_cgroup_per_zone *mz;
-
- spin_lock(&mctz->lock);
- mz = __mem_cgroup_largest_soft_limit_node(mctz);
- spin_unlock(&mctz->lock);
- return mz;
-}
-
/*
* Implementation Note: reading percpu statistics for memcg.
*
@@ -583,15 +393,6 @@ static long mem_cgroup_read_stat(struct mem_cgroup *mem,
return val;
}

-static long mem_cgroup_local_usage(struct mem_cgroup *mem)
-{
- long ret;
-
- ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
- ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
- return ret;
-}
-
static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
bool charge)
{
@@ -710,7 +511,6 @@ static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
__mem_cgroup_target_update(mem, MEM_CGROUP_TARGET_THRESH);
if (unlikely(__memcg_event_check(mem,
MEM_CGROUP_TARGET_SOFTLIMIT))){
- mem_cgroup_update_tree(mem, page);
__mem_cgroup_target_update(mem,
MEM_CGROUP_TARGET_SOFTLIMIT);
}
@@ -1520,103 +1320,6 @@ static unsigned long mem_cgroup_reclaim(struct mem_cgroup *mem,
}

/*
- * Visit the first child (need not be the first child as per the ordering
- * of the cgroup list, since we track last_scanned_child) of @mem and use
- * that to reclaim free pages from.
- */
-static struct mem_cgroup *
-mem_cgroup_select_victim(struct mem_cgroup *root_mem)
-{
- struct mem_cgroup *ret = NULL;
- struct cgroup_subsys_state *css;
- int nextid, found;
-
- if (!root_mem->use_hierarchy) {
- css_get(&root_mem->css);
- ret = root_mem;
- }
-
- while (!ret) {
- rcu_read_lock();
- nextid = root_mem->last_scanned_child + 1;
- css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
- &found);
- if (css && css_tryget(css))
- ret = container_of(css, struct mem_cgroup, css);
-
- rcu_read_unlock();
- /* Updates scanning parameter */
- if (!css) {
- /* this means start scan from ID:1 */
- root_mem->last_scanned_child = 0;
- } else
- root_mem->last_scanned_child = found;
- }
-
- return ret;
-}
-
-static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_mem,
- struct zone *zone,
- gfp_t gfp_mask)
-{
- struct mem_cgroup *victim;
- int ret, total = 0;
- int loop = 0;
- bool noswap = false;
- unsigned long excess;
-
- excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
-
- /* If memsw_is_minimum==1, swap-out is of-no-use. */
- if (root_mem->memsw_is_minimum)
- noswap = true;
-
- while (1) {
- victim = mem_cgroup_select_victim(root_mem);
- if (victim == root_mem) {
- loop++;
- if (loop >= 1)
- drain_all_stock_async();
- 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) {
- css_put(&victim->css);
- 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)) {
- css_put(&victim->css);
- break;
- }
- }
- }
- if (!mem_cgroup_local_usage(victim)) {
- /* this cgroup's local usage == 0 */
- css_put(&victim->css);
- continue;
- }
- ret = mem_cgroup_shrink_node_zone(victim, gfp_mask, noswap,
- get_swappiness(victim), zone);
- css_put(&victim->css);
- total += ret;
- if (!res_counter_soft_limit_excess(&root_mem->res))
- return total;
- }
- return total;
-}
-
-/*
* Check OOM-Killer is already running under our hierarchy.
* If someone is running, return false.
*/
@@ -2310,8 +2013,6 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
unlock_page_cgroup(pc);
/*
* "charge_statistics" updated event counter. Then, check it.
- * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
- * if they exceeds softlimit.
*/
memcg_check_events(mem, page);
}
@@ -3391,94 +3092,6 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
return ret;
}

-unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
- gfp_t gfp_mask)
-{
- unsigned long nr_reclaimed = 0;
- struct mem_cgroup_per_zone *mz, *next_mz = NULL;
- unsigned long reclaimed;
- int loop = 0;
- struct mem_cgroup_tree_per_zone *mctz;
- unsigned long long excess;
-
- if (order > 0)
- return 0;
-
- mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
- /*
- * 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->mem, zone, gfp_mask);
- nr_reclaimed += reclaimed;
- spin_lock(&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) {
- do {
- /*
- * Loop until we find yet another one.
- *
- * By the time we get the soft_limit lock
- * again, someone might have aded the
- * group back on the RB tree. Iterate to
- * make sure we get a different mem.
- * mem_cgroup_largest_soft_limit_node returns
- * NULL if no other cgroup is present on
- * the tree
- */
- next_mz =
- __mem_cgroup_largest_soft_limit_node(mctz);
- if (next_mz == mz) {
- css_put(&next_mz->mem->css);
- next_mz = NULL;
- } else /* next_mz == NULL or other memcg */
- break;
- } while (1);
- }
- __mem_cgroup_remove_exceeded(mz->mem, mz, mctz);
- excess = res_counter_soft_limit_excess(&mz->mem->res);
- /*
- * 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->mem, mz, mctz, excess);
- spin_unlock(&mctz->lock);
- css_put(&mz->mem->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->mem->css);
- return nr_reclaimed;
-}
-
/*
* This routine traverse page_cgroup in given list and drop them all.
* *And* this routine doesn't reclaim page itself, just removes page_cgroup.
@@ -4548,9 +4161,6 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
mz = &pn->zoneinfo[zone];
for_each_lru(l)
INIT_LIST_HEAD(&mz->lists[l]);
- mz->usage_in_excess = 0;
- mz->on_tree = false;
- mz->mem = mem;
}
return 0;
}
@@ -4603,7 +4213,6 @@ static void __mem_cgroup_free(struct mem_cgroup *mem)
{
int node;

- mem_cgroup_remove_from_trees(mem);
free_css_id(&mem_cgroup_subsys, &mem->css);

for_each_node_state(node, N_POSSIBLE)
@@ -4658,31 +4267,6 @@ static void __init enable_swap_cgroup(void)
}
#endif

-static int mem_cgroup_soft_limit_tree_init(void)
-{
- struct mem_cgroup_tree_per_node *rtpn;
- struct mem_cgroup_tree_per_zone *rtpz;
- int tmp, node, zone;
-
- for_each_node_state(node, N_POSSIBLE) {
- tmp = node;
- if (!node_state(node, N_NORMAL_MEMORY))
- tmp = -1;
- rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
- if (!rtpn)
- return 1;
-
- soft_limit_tree.rb_tree_per_node[node] = rtpn;
-
- for (zone = 0; zone < MAX_NR_ZONES; zone++) {
- rtpz = &rtpn->rb_tree_per_zone[zone];
- rtpz->rb_root = RB_ROOT;
- spin_lock_init(&rtpz->lock);
- }
- }
- return 0;
-}
-
static struct cgroup_subsys_state * __ref
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
@@ -4704,8 +4288,6 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
enable_swap_cgroup();
parent = NULL;
root_mem_cgroup = mem;
- if (mem_cgroup_soft_limit_tree_init())
- goto free_out;
for_each_possible_cpu(cpu) {
struct memcg_stock_pcp *stock =
&per_cpu(memcg_stock, cpu);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 0163840..7d74e48 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2213,43 +2213,6 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
}

#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-
-unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
- gfp_t gfp_mask, bool noswap,
- unsigned int swappiness,
- struct zone *zone)
-{
- struct scan_control sc = {
- .nr_to_reclaim = SWAP_CLUSTER_MAX,
- .may_writepage = !laptop_mode,
- .may_unmap = 1,
- .may_swap = !noswap,
- .swappiness = swappiness,
- .order = 0,
- .target_mem_cgroup = mem,
- .mem_cgroup = mem,
- };
- sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
- (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
-
- trace_mm_vmscan_memcg_softlimit_reclaim_begin(0,
- sc.may_writepage,
- sc.gfp_mask);
-
- /*
- * NOTE: Although we can get the priority field, using it
- * here is not a good idea, since it limits the pages we can scan.
- * if we don't reclaim here, the shrink_zone from balance_pgdat
- * will pick up pages from other mem cgroup's as well. We hack
- * the priority and make it zero.
- */
- do_shrink_zone(0, zone, &sc);
-
- trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);
-
- return sc.nr_reclaimed;
-}
-
unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
gfp_t gfp_mask,
bool noswap,
@@ -2479,13 +2442,6 @@ loop_again:
continue;

sc.nr_scanned = 0;
-
- /*
- * Call soft limit reclaim before calling shrink_zone.
- * For now we ignore the return value
- */
- //mem_cgroup_soft_limit_reclaim(zone, order, sc.gfp_mask);
-
/*
* We put equal pressure on every zone, unless
* one zone has way too many pages free
--
1.7.5.2