The patch titled
memcg: make resize limit hold mutex
has been added to the -mm tree. Its filename is
memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memcg: make resize limit hold mutex
From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
mem_cgroup_resize_memsw_limit() try to hold memsw.lock while holding
res.lock, so below message is showed when trying to write
memory.memsw.limit_in_bytes file.
[ INFO: possible recursive locking detected ]
2.6.28-rc4-mm1-mmotm-2008-11-14-20-50-ef4e17ef #1
bash/4406 is trying to acquire lock:
(&counter->lock){....}, at: [<c0498408>] mem_cgroup_resize_memsw_limit+0x8d/0x113
but task is already holding lock:
(&counter->lock){....}, at: [<c04983d6>] mem_cgroup_resize_memsw_limit+0x5b/0x113
other info that might help us debug this:
1 lock held by bash/4406:
#0: (&counter->lock){....}, at: [<c04983d6>] mem_cgroup_resize_memsw_limit+0x5b/0x113
stack backtrace:
Pid: 4406, comm: bash Not tainted 2.6.28-rc4-mm1-mmotm-2008-11-14-20-50-ef4e17ef #1
Call Trace:
[<c066e60f>] ? printk+0xf/0x18
[<c044d0c0>] __lock_acquire+0xc67/0x1353
[<c044d793>] ? __lock_acquire+0x133a/0x1353
[<c044d81c>] lock_acquire+0x70/0x97
[<c0498408>] ? mem_cgroup_resize_memsw_limit+0x8d/0x113
[<c0671519>] _spin_lock_irqsave+0x3a/0x6d
[<c0498408>] ? mem_cgroup_resize_memsw_limit+0x8d/0x113
[<c0498408>] mem_cgroup_resize_memsw_limit+0x8d/0x113
[<c0518a6c>] ? memparse+0x14/0x66
[<c0498594>] mem_cgroup_write+0x4a/0x50
[<c045e063>] cgroup_file_write+0x181/0x1c6
[<c0449e43>] ? lock_release_holdtime+0x1a/0x168
[<c04ec725>] ? security_file_permission+0xf/0x11
[<c049b5f0>] ? rw_verify_area+0x76/0x97
[<c045dee2>] ? cgroup_file_write+0x0/0x1c6
[<c049bce6>] vfs_write+0x8a/0x12e
[<c049be23>] sys_write+0x3b/0x60
[<c0403867>] sysenter_do_call+0x12/0x3f
This patch define a new mutex and make both mem_cgroup_resize_limit and
mem_cgroup_memsw_resize_limit hold it to remove spin_lock_irqsave.
Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 40 ++++++++++++++++++++++++++--------------
1 file changed, 26 insertions(+), 14 deletions(-)
diff -puN mm/memcontrol.c~memcg-memswap-controller-core-make-resize-limit-hold-mutex mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-memswap-controller-core-make-resize-limit-hold-mutex
+++ a/mm/memcontrol.c
@@ -27,6 +27,7 @@
#include <linux/backing-dev.h>
#include <linux/bit_spinlock.h>
#include <linux/rcupdate.h>
+#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/spinlock.h>
@@ -1189,27 +1190,38 @@ int mem_cgroup_shrink_usage(struct mm_st
return 0;
}
+static DEFINE_MUTEX(set_limit_mutex);
int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
{
int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
int progress;
+ u64 memswlimit;
int ret = 0;
- if (do_swap_account) {
- if (val > memcg->memsw.limit)
- return -EINVAL;
- }
-
- while (res_counter_set_limit(&memcg->res, val)) {
+ while (retry_count) {
if (signal_pending(current)) {
ret = -EINTR;
break;
}
- if (!retry_count) {
- ret = -EBUSY;
+ /*
+ * Rather than hide all in some function, I do this in
+ * open coded manner. You see what this really does.
+ * We have to guarantee mem->res.limit < mem->memsw.limit.
+ */
+ mutex_lock(&set_limit_mutex);
+ memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+ if (memswlimit < val) {
+ ret = -EINVAL;
+ mutex_unlock(&set_limit_mutex);
break;
}
+ ret = res_counter_set_limit(&memcg->res, val);
+ mutex_unlock(&set_limit_mutex);
+
+ if (!ret)
+ break;
+
progress = try_to_free_mem_cgroup_pages(memcg,
GFP_HIGHUSER_MOVABLE, false);
if (!progress)
@@ -1222,7 +1234,6 @@ int mem_cgroup_resize_memsw_limit(struct
unsigned long long val)
{
int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
- unsigned long flags;
u64 memlimit, oldusage, curusage;
int ret;
@@ -1239,19 +1250,20 @@ int mem_cgroup_resize_memsw_limit(struct
* open coded manner. You see what this really does.
* We have to guarantee mem->res.limit < mem->memsw.limit.
*/
- spin_lock_irqsave(&memcg->res.lock, flags);
- memlimit = memcg->res.limit;
+ mutex_lock(&set_limit_mutex);
+ memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
if (memlimit > val) {
- spin_unlock_irqrestore(&memcg->res.lock, flags);
ret = -EINVAL;
+ mutex_unlock(&set_limit_mutex);
break;
}
ret = res_counter_set_limit(&memcg->memsw, val);
- oldusage = memcg->memsw.usage;
- spin_unlock_irqrestore(&memcg->res.lock, flags);
+ mutex_unlock(&set_limit_mutex);
if (!ret)
break;
+
+ oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
try_to_free_mem_cgroup_pages(memcg, GFP_HIGHUSER_MOVABLE, true);
curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
if (curusage >= oldusage)
_
Patches currently in -mm which might be from nishimura@xxxxxxxxxxxxxxxxx are
cgroup-fix-potential-deadlock-in-pre_destroy-v2.patch
cgroups-make-cgroup-config-a-submenu.patch
memcg-introduce-charge-commit-cancel-style-of-functions.patch
memcg-introduce-charge-commit-cancel-style-of-functions-fix.patch
memcg-fix-gfp_mask-of-callers-of-charge.patch
memcg-simple-migration-handling.patch
memcg-do-not-recalculate-section-unnecessarily-in-init_section_page_cgroup.patch
memcg-move-all-acccounts-to-parent-at-rmdir.patch
memcg-handle-swap-caches.patch
memcg-memswap-controller-kconfig.patch
memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
