[Fedora PATCH] Improve Resource Counter Scalability
Prarit Bhargava
prarit at redhat.com
Mon Oct 12 15:54:33 UTC 2009
This patch was sent to me by Balbir Singh, cc'd, who worked on the original
patch. The patch results in a massive increase in performance on a 64p/32G
system. The patch was successfully compiled and tested by me on fedora-latest.
>From the upstream commit:
"Data from Prarit (kernel compile with make -j64 on a 64
CPU/32G machine)
For a single run
Without patch
real 27m8.988s
user 87m24.916s
sys 382m6.037s
With patch
real 4m18.607s
user 84m58.943s
sys 50m52.682s
With config turned off
real 4m54.972s
user 90m13.456s
sys 50m19.711s
NOTE: The data looks counterintuitive due to the increased performance
with the patch, even over the config being turned off. We probably need
more runs, but so far all testing has shown that the patches definitely
help."
-------------------------------------------------------------------------------
Backport 0c3e73e84fe3f64cf1c2e8bb4e91e8901cbcdc38
From: Balbir Singh <balbir at linux.vnet.ibm.com>
(memcg: improve resource counter scalability) to 2.6.31.
It is a very useful patch for non-users of memory control
group as it reduces the overhead quite significantly.
Signed-off-by: Balbir Singh <balbir at linux.vnet.ibm.com>
---
mm/memcontrol.c | 127 ++++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 106 insertions(+), 21 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fd4529d..4821be0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -43,6 +43,7 @@
struct cgroup_subsys mem_cgroup_subsys __read_mostly;
#define MEM_CGROUP_RECLAIM_RETRIES 5
+struct mem_cgroup *root_mem_cgroup __read_mostly;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
@@ -66,6 +67,7 @@ enum mem_cgroup_stat_index {
MEM_CGROUP_STAT_MAPPED_FILE, /* # of pages charged as file rss */
MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
+ MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
MEM_CGROUP_STAT_NSTATS,
};
@@ -219,11 +221,24 @@ static void mem_cgroup_get(struct mem_cgroup *mem);
static void mem_cgroup_put(struct mem_cgroup *mem);
static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
+static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
+ bool charge)
+{
+ int val = (charge) ? 1 : -1;
+ struct mem_cgroup_stat *stat = &mem->stat;
+ struct mem_cgroup_stat_cpu *cpustat;
+ int cpu = get_cpu();
+
+ cpustat = &stat->cpustat[cpu];
+ __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_SWAPOUT, val);
+ put_cpu();
+}
+
static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
struct page_cgroup *pc,
bool charge)
{
- int val = (charge)? 1 : -1;
+ int val = (charge) ? 1 : -1;
struct mem_cgroup_stat *stat = &mem->stat;
struct mem_cgroup_stat_cpu *cpustat;
int cpu = get_cpu();
@@ -354,6 +369,11 @@ static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
return ret;
}
+static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
+{
+ return (mem == root_mem_cgroup);
+}
+
/*
* Following LRU functions are allowed to be used without PCG_LOCK.
* Operations are called by routine of global LRU independently from memcg.
@@ -996,9 +1016,11 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
VM_BUG_ON(css_is_removed(&mem->css));
while (1) {
- int ret;
+ int ret = 0;
bool noswap = false;
+ if (mem_cgroup_is_root(mem))
+ goto done;
ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
if (likely(!ret)) {
if (!do_swap_account)
@@ -1046,6 +1068,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
goto nomem;
}
}
+done:
return 0;
nomem:
css_put(&mem->css);
@@ -1119,9 +1142,11 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
lock_page_cgroup(pc);
if (unlikely(PageCgroupUsed(pc))) {
unlock_page_cgroup(pc);
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- if (do_swap_account)
- res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+ if (!mem_cgroup_is_root(mem)) {
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ if (do_swap_account)
+ res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+ }
css_put(&mem->css);
return;
}
@@ -1178,7 +1203,8 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
if (pc->mem_cgroup != from)
goto out;
- res_counter_uncharge(&from->res, PAGE_SIZE);
+ if (!mem_cgroup_is_root(from))
+ res_counter_uncharge(&from->res, PAGE_SIZE);
mem_cgroup_charge_statistics(from, pc, false);
page = pc->page;
@@ -1197,7 +1223,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc,
1);
}
- if (do_swap_account)
+ if (do_swap_account && !mem_cgroup_is_root(from))
res_counter_uncharge(&from->memsw, PAGE_SIZE);
css_put(&from->css);
@@ -1268,9 +1294,11 @@ uncharge:
/* drop extra refcnt by try_charge() */
css_put(&parent->css);
/* uncharge if move fails */
- res_counter_uncharge(&parent->res, PAGE_SIZE);
- if (do_swap_account)
- res_counter_uncharge(&parent->memsw, PAGE_SIZE);
+ if (!mem_cgroup_is_root(parent)) {
+ res_counter_uncharge(&parent->res, PAGE_SIZE);
+ if (do_swap_account)
+ res_counter_uncharge(&parent->memsw, PAGE_SIZE);
+ }
return ret;
}
@@ -1459,7 +1487,9 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
* This recorded memcg can be obsolete one. So, avoid
* calling css_tryget
*/
- res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+ if (!mem_cgroup_is_root(memcg))
+ res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+ mem_cgroup_swap_statistics(memcg, false);
mem_cgroup_put(memcg);
}
rcu_read_unlock();
@@ -1484,9 +1514,11 @@ void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
return;
if (!mem)
return;
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- if (do_swap_account)
- res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+ if (!mem_cgroup_is_root(mem)) {
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ if (do_swap_account)
+ res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+ }
css_put(&mem->css);
}
@@ -1538,9 +1570,14 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
break;
}
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
- res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+ if (!mem_cgroup_is_root(mem)) {
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ if (do_swap_account &&
+ (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
+ res_counter_uncharge(&mem->memsw, PAGE_SIZE);
+ }
+ if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
+ mem_cgroup_swap_statistics(mem, true);
mem_cgroup_charge_statistics(mem, pc, false);
ClearPageCgroupUsed(pc);
@@ -1629,7 +1666,9 @@ void mem_cgroup_uncharge_swap(swp_entry_t ent)
* We uncharge this because swap is freed.
* This memcg can be obsolete one. We avoid calling css_tryget
*/
- res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+ if (!mem_cgroup_is_root(memcg))
+ res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
+ mem_cgroup_swap_statistics(memcg, false);
mem_cgroup_put(memcg);
}
rcu_read_unlock();
@@ -2046,20 +2085,64 @@ static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
return retval;
}
+struct mem_cgroup_idx_data {
+ s64 val;
+ enum mem_cgroup_stat_index idx;
+};
+
+static int
+mem_cgroup_get_idx_stat(struct mem_cgroup *mem, void *data)
+{
+ struct mem_cgroup_idx_data *d = data;
+ d->val += mem_cgroup_read_stat(&mem->stat, d->idx);
+ return 0;
+}
+
+static void
+mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem,
+ enum mem_cgroup_stat_index idx, s64 *val)
+{
+ struct mem_cgroup_idx_data d;
+ d.idx = idx;
+ d.val = 0;
+ mem_cgroup_walk_tree(mem, &d, mem_cgroup_get_idx_stat);
+ *val = d.val;
+}
+
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
- u64 val = 0;
+ u64 idx_val, val;
int type, name;
type = MEMFILE_TYPE(cft->private);
name = MEMFILE_ATTR(cft->private);
switch (type) {
case _MEM:
- val = res_counter_read_u64(&mem->res, name);
+ if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
+ mem_cgroup_get_recursive_idx_stat(mem,
+ MEM_CGROUP_STAT_CACHE, &idx_val);
+ val = idx_val;
+ mem_cgroup_get_recursive_idx_stat(mem,
+ MEM_CGROUP_STAT_RSS, &idx_val);
+ val += idx_val;
+ val <<= PAGE_SHIFT;
+ } else
+ val = res_counter_read_u64(&mem->res, name);
break;
case _MEMSWAP:
- val = res_counter_read_u64(&mem->memsw, name);
+ if (name == RES_USAGE && mem_cgroup_is_root(mem)) {
+ mem_cgroup_get_recursive_idx_stat(mem,
+ MEM_CGROUP_STAT_CACHE, &idx_val);
+ val = idx_val;
+ mem_cgroup_get_recursive_idx_stat(mem,
+ MEM_CGROUP_STAT_RSS, &idx_val);
+ val += idx_val;
+ mem_cgroup_get_recursive_idx_stat(mem,
+ MEM_CGROUP_STAT_SWAPOUT, &idx_val);
+ val <<= PAGE_SHIFT;
+ } else
+ val = res_counter_read_u64(&mem->memsw, name);
break;
default:
BUG();
@@ -2548,6 +2631,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
/* root ? */
if (cont->parent == NULL) {
enable_swap_cgroup();
+ root_mem_cgroup = mem;
parent = NULL;
} else {
parent = mem_cgroup_from_cont(cont->parent);
@@ -2577,6 +2661,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
return &mem->css;
free_out:
__mem_cgroup_free(mem);
+ root_mem_cgroup = NULL;
return ERR_PTR(error);
}
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