The patch titled
cgroups: add res_counter_write_u64() API
has been added to the -mm tree. Its filename is
cgroups-add-res_counter_write_u64-api.patch
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Subject: cgroups: add res_counter_write_u64() API
From: Frederic Weisbecker <fweisbec@xxxxxxxxx>
The task counter is a cgroup subsystem that features an upper bound
limitation on the number of tasks running inside cgroup.
It has two desired usecases, but possibly more can be found:
- Protect against forkbomb in the scope of a cgroup, this can be
especially useful in the case of containers where traditional rlmit is
too limited.
- Kill all tasks inside a cgroup without worrying about races against
concurrent forks.
See documentation in patch 10/12 for more details.
This patch: Add res_counter_write_u64() API
Extend the resource counter API with a mirror of res_counter_read_u64() to
make it handy to update a resource counter value from a cgroup subsystem
u64 value file.
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Acked-by: Paul Menage <paul@xxxxxxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Aditya Kali <adityakali@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Kay Sievers <kay.sievers@xxxxxxxx>
Cc: Tim Hockin <thockin@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/res_counter.h | 2 ++
kernel/res_counter.c | 25 +++++++++++++++++++------
2 files changed, 21 insertions(+), 6 deletions(-)
diff -puN include/linux/res_counter.h~cgroups-add-res_counter_write_u64-api include/linux/res_counter.h
--- a/include/linux/res_counter.h~cgroups-add-res_counter_write_u64-api
+++ a/include/linux/res_counter.h
@@ -82,6 +82,8 @@ int res_counter_memparse_write_strategy(
int res_counter_write(struct res_counter *counter, int member,
const char *buffer, write_strategy_fn write_strategy);
+void res_counter_write_u64(struct res_counter *counter, int member, u64 val);
+
/*
* the field descriptors. one for each member of res_counter
*/
diff -puN kernel/res_counter.c~cgroups-add-res_counter_write_u64-api kernel/res_counter.c
--- a/kernel/res_counter.c~cgroups-add-res_counter_write_u64-api
+++ a/kernel/res_counter.c
@@ -168,12 +168,26 @@ int res_counter_memparse_write_strategy(
return 0;
}
+void res_counter_write_u64(struct res_counter *counter, int member, u64 val)
+{
+ unsigned long long *target;
+ unsigned long flags;
+
+ /*
+ * We need the lock to protect against concurrent add/dec on 32 bits.
+ * No need to ifdef it's seldom used.
+ */
+ spin_lock_irqsave(&counter->lock, flags);
+ target = res_counter_member(counter, member);
+ *target = val;
+ spin_unlock_irqrestore(&counter->lock, flags);
+}
+
int res_counter_write(struct res_counter *counter, int member,
const char *buf, write_strategy_fn write_strategy)
{
char *end;
- unsigned long flags;
- unsigned long long tmp, *val;
+ unsigned long long tmp;
if (write_strategy) {
if (write_strategy(buf, &tmp))
@@ -183,9 +197,8 @@ int res_counter_write(struct res_counter
if (*end != '\0')
return -EINVAL;
}
- spin_lock_irqsave(&counter->lock, flags);
- val = res_counter_member(counter, member);
- *val = tmp;
- spin_unlock_irqrestore(&counter->lock, flags);
+
+ res_counter_write_u64(counter, member, tmp);
+
return 0;
}
_
Patches currently in -mm which might be from fweisbec@xxxxxxxxx are
linux-next.patch
tracex86-add-tracepoint-to-x86-timer-interrupt-handler.patch
tracex86-add-x86-irq-vector-entry-exit-tracepoints.patch
cgroups-more-safe-tasklist-locking-in-cgroup_attach_proc.patch
cgroups-fix-ordering-of-calls-in-cgroup_attach_proc.patch
cgroups-add-res_counter_write_u64-api.patch
cgroups-new-resource-counter-inheritance-api.patch
cgroups-add-previous-cgroup-in-can_attach_task-attach_task-callbacks.patch
cgroups-new-cancel_attach_task-subsystem-callback.patch
cgroups-new-cancel_attach_task-subsystem-callback-fix.patch
cgroups-ability-to-stop-res-charge-propagation-on-bounded-ancestor.patch
cgroups-add-res-counter-common-ancestor-searching.patch
cgroups-add-res-counter-common-ancestor-searching-fix.patch
res_counter-allow-charge-failure-pointer-to-be-null.patch
cgroups-pull-up-res-counter-charge-failure-interpretation-to-caller.patch
cgroups-add-a-task-counter-subsystem.patch
cgroups-add-documentation-for-task-counter-subsystem.patch
cgroups-allow-subsystems-to-cancel-a-fork.patch
cgroups-convert-task-counter-to-use-the-subsys-fork-callback.patch
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