On Tue, Jan 13, 2009 at 4:44 AM, Tim Blechmann <tim@xxxxxxxxxx> wrote:
> fyi, this is still an issue in 2.6.26.8-rt13.
>
> tim
The attached patch should fix it ; it is based on the discussion
that took place here on rt-users.
Paul.
>
> Tim Blechmann wrote:
>
>> hi all,
>>
>> using the 2.6.26.6-rt11 patchset on a 2.6.26.8 kernel, i get the
>> following stack traces:
>>
>> [ 4262.931832] BUG: using smp_processor_id() in preemptible [00000000]
>> code: bash/361 [ 4262.931846] caller is
>> mem_cgroup_charge_statistics+0x6d/0xa0 [ 4262.931852] Pid: 361, comm:
>> bash Not tainted 2.6.26.8-rt11 #3 [ 4262.931855]
>> [ 4262.931856] Call Trace:
>> [ 4262.931886] [<ffffffff80396e8c>] debug_smp_processor_id+0xcc/0xd0 [
>> 4262.931895] [<ffffffff802daead>]
>> mem_cgroup_charge_statistics+0x6d/0xa0 [ 4262.931905]
From faa0ea31405ec9d44e8242e224f8e607642f3c5e Mon Sep 17 00:00:00 2001
From: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Date: Mon, 26 Jan 2009 21:15:22 -0500
Subject: [PATCH] memcg: fix BUG: using smp_processor_id() in preemptible
A combination of upstream (e.g. addb9efe) and as per discussion
on rt list (Dec 2008) between Tim Blechmann and Kamezawa Hiroyuki,
this is needed to fix the following:
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/1
caller is mem_cgroup_charge_statistics+0x85/0xa0
Pid: 1, comm: swapper Not tainted 2.6.26.8-rt12 #1
Call Trace:
[<ffffffff8038eb94>] debug_smp_processor_id+0xc4/0xd0
[<ffffffff8029ffe5>] mem_cgroup_charge_statistics+0x85/0xa0
[<ffffffff802a0039>] __mem_cgroup_add_list+0x39/0x60
[<ffffffff802a0807>] mem_cgroup_charge_common+0x317/0x340
[<ffffffff802a0849>] mem_cgroup_cache_charge+0x19/0x20
[<ffffffff80276918>] add_to_page_cache+0x38/0x250
[<ffffffff8027d43d>] ? __alloc_pages_internal+0xed/0x4f0
[<ffffffff80276b49>] add_to_page_cache_lru+0x19/0x40
[<ffffffff80277603>] find_or_create_page+0x63/0xb0
[<ffffffff802cd401>] __getblk+0x101/0x320
[<ffffffff802fddd6>] __ext3_get_inode_loc+0x106/0x320
[<ffffffff802fe060>] ext3_iget+0x70/0x420
[<ffffffff80305068>] ext3_lookup+0xa8/0x100
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
mm/memcontrol.c | 19 ++++++++++++-------
1 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ed1cfb1..86e7f14 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -65,11 +65,11 @@ struct mem_cgroup_stat {
/*
* For accounting under irq disable, no need for increment preempt count.
*/
-static void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat *stat,
+static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat,
enum mem_cgroup_stat_index idx, int val)
{
- int cpu = smp_processor_id();
- stat->cpustat[cpu].count[idx] += val;
+ stat->count[idx] += val;
+
}
static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
@@ -195,19 +195,24 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags,
{
int val = (charge)? 1 : -1;
struct mem_cgroup_stat *stat = &mem->stat;
+ struct mem_cgroup_stat_cpu *cpustat;
+ int cpu = get_cpu();
VM_BUG_ON(!irqs_disabled());
+
+ cpustat = &stat->cpustat[cpu];
if (flags & PAGE_CGROUP_FLAG_CACHE)
- __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_CACHE, val);
+ __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
else
- __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val);
+ __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
if (charge)
- __mem_cgroup_stat_add_safe(stat,
+ __mem_cgroup_stat_add_safe(cpustat,
MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
else
- __mem_cgroup_stat_add_safe(stat,
+ __mem_cgroup_stat_add_safe(cpustat,
MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
+ put_cpu();
}
static struct mem_cgroup_per_zone *
--
1.6.0.4
