Home » Mailing lists » Devel » [RFC 0/7] Initial proposal for faster res_counter updates
| [RFC 2/7] consolidate all res_counter manipulation [message #45716 is a reply to message #45710] |
Fri, 30 March 2012 08:04   |
Glauber Costa
Messages: 916
Registered: October 2011
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Senior Member |
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This patch moves all the locked updates done to res_counter to
__res_counter_add(). It gets flags for the special cases like nofail(),
and a negative value of the increment means uncharge.
This will be useful later when we start doing percpu_counter updates.
Signed-off-by: Glauber Costa <glommer@parallels.com>
---
kernel/res_counter.c | 59 +++++++++++++++++++++++--------------------------
1 files changed, 28 insertions(+), 31 deletions(-)
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index b8a3d6a..ecb4aad 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -22,17 +22,32 @@ void res_counter_init(struct res_counter *counter, struct res_counter *parent)
counter->parent = parent;
}
-int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
+int __res_counter_add(struct res_counter *c, long val, bool fail)
{
- if (counter->usage + val > counter->limit) {
- counter->failcnt++;
- return -ENOMEM;
+ int ret = 0;
+ u64 usage;
+
+ spin_lock(&c->lock);
+
+ usage = c->usage;
+
+ if (usage + val > c->limit) {
+ c->failcnt++;
+ ret = -ENOMEM;
+ if (fail)
+ goto out;
}
- counter->usage += val;
- if (counter->usage > counter->max_usage)
- counter->max_usage = counter->usage;
- return 0;
+ usage += val;
+
+ c->usage = usage;
+ if (usage > c->max_usage)
+ c->max_usage = usage;
+
+out:
+ spin_unlock(&c->lock);
+ return ret;
+
}
int res_counter_charge(struct res_counter *counter, unsigned long val,
@@ -45,9 +60,7 @@ int res_counter_charge(struct res_counter *counter, unsigned long val,
*limit_fail_at = NULL;
local_irq_save(flags);
for (c = counter; c != NULL; c = c->parent) {
- spin_lock(&c->lock);
- ret = res_counter_charge_locked(c, val);
- spin_unlock(&c->lock);
+ ret = __res_counter_add(c, val, true);
if (ret < 0) {
*limit_fail_at = c;
goto undo;
@@ -57,9 +70,7 @@ int res_counter_charge(struct res_counter *counter, unsigned long val,
goto done;
undo:
for (u = counter; u != c; u = u->parent) {
- spin_lock(&u->lock);
- res_counter_uncharge_locked(u, val);
- spin_unlock(&u->lock);
+ __res_counter_add(u, -val, false);
}
done:
local_irq_restore(flags);
@@ -77,11 +88,7 @@ int res_counter_charge_nofail(struct res_counter *counter, unsigned long val,
*limit_fail_at = NULL;
local_irq_save(flags);
for (c = counter; c != NULL; c = c->parent) {
- spin_lock(&c->lock);
- r = res_counter_charge_locked(c, val);
- if (r)
- c->usage += val;
- spin_unlock(&c->lock);
+ r = __res_counter_add(c, val, false);
if (r < 0 && ret == 0) {
*limit_fail_at = c;
ret = r;
@@ -91,13 +98,6 @@ int res_counter_charge_nofail(struct res_counter *counter, unsigned long val,
return ret;
}
-void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
-{
- if (WARN_ON(counter->usage < val))
- val = counter->usage;
-
- counter->usage -= val;
-}
void res_counter_uncharge(struct res_counter *counter, unsigned long val)
{
@@ -105,11 +105,8 @@ void res_counter_uncharge(struct res_counter *counter, unsigned long val)
struct res_counter *c;
local_irq_save(flags);
- for (c = counter; c != NULL; c = c->parent) {
- spin_lock(&c->lock);
- res_counter_uncharge_locked(c, val);
- spin_unlock(&c->lock);
- }
+ for (c = counter; c != NULL; c = c->parent)
+ __res_counter_add(c, -val, false);
local_irq_restore(flags);
}
--
1.7.4.1
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