[PATCH] Show kernel stack usage to /proc/meminfo and OOM log

From: KOSAKI Motohiro
Date: Tue Jun 30 2009 - 02:04:03 EST


Recent "Found the commit that causes the OOMs" discussion notice us that kernel
stack usage should be showed in OOM log.

At least, I think ;)

this patch provide it.


========
Subject: [PATCH] Show kernel stack usage to /proc/meminfo and OOM log

if the system have a lot of thread, kernel stack consume unignorable large size
memory.
IOW, it make a lot of unaccountable memory.

Tons unaccountable memory bring to harder analyse memory related trouble.

Then, kernel stack account is useful.
---
fs/proc/meminfo.c | 2 ++
include/linux/mmzone.h | 3 ++-
kernel/fork.c | 13 +++++++++++++
mm/page_alloc.c | 6 ++++--
mm/vmstat.c | 1 +
5 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index d5c410d..1fbf8c0 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -85,6 +85,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
"SReclaimable: %8lu kB\n"
"SUnreclaim: %8lu kB\n"
"PageTables: %8lu kB\n"
+ "KernelStack %8lu kB\n"
#ifdef CONFIG_QUICKLIST
"Quicklists: %8lu kB\n"
#endif
@@ -129,6 +130,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
K(global_page_state(NR_SLAB_RECLAIMABLE)),
K(global_page_state(NR_SLAB_UNRECLAIMABLE)),
K(global_page_state(NR_PAGETABLE)),
+ K(global_page_state(NR_KERNEL_STACK)),
#ifdef CONFIG_QUICKLIST
K(quicklist_total_size()),
#endif
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 8895985..d9335b8 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -94,10 +94,11 @@ enum zone_stat_item {
NR_SLAB_RECLAIMABLE,
NR_SLAB_UNRECLAIMABLE,
NR_PAGETABLE, /* used for pagetables */
+ NR_KERNEL_STACK,
+ /* Second 128 byte cacheline */
NR_UNSTABLE_NFS, /* NFS unstable pages */
NR_BOUNCE,
NR_VMSCAN_WRITE,
- /* Second 128 byte cacheline */
NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */
#ifdef CONFIG_NUMA
NUMA_HIT, /* allocated in intended node */
diff --git a/kernel/fork.c b/kernel/fork.c
index 467746b..21cd4aa 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -137,9 +137,19 @@ struct kmem_cache *vm_area_cachep;
/* SLAB cache for mm_struct structures (tsk->mm) */
static struct kmem_cache *mm_cachep;

+static void account_kernel_stack(struct thread_info *ti, int on)
+{
+ struct zone* zone = page_zone(virt_to_page(ti));
+ int sign = on ? 1 : -1;
+ long acct = sign * (THREAD_SIZE / PAGE_SIZE);
+
+ mod_zone_page_state(zone, NR_KERNEL_STACK, acct);
+}
+
void free_task(struct task_struct *tsk)
{
prop_local_destroy_single(&tsk->dirties);
+ account_kernel_stack(tsk->stack, 0);
free_thread_info(tsk->stack);
rt_mutex_debug_task_free(tsk);
ftrace_graph_exit_task(tsk);
@@ -255,6 +265,9 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
tsk->btrace_seq = 0;
#endif
tsk->splice_pipe = NULL;
+
+ account_kernel_stack(ti, 1);
+
return tsk;

out:
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 30d5093..0edec1c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2119,7 +2119,8 @@ void show_free_areas(void)
" inactive_file:%lu"
" unevictable:%lu"
" dirty:%lu writeback:%lu unstable:%lu\n"
- " free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
+ " free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n"
+ " kernel_stack:%lu\n",
global_page_state(NR_ACTIVE_ANON),
global_page_state(NR_ACTIVE_FILE),
global_page_state(NR_INACTIVE_ANON),
@@ -2133,7 +2134,8 @@ void show_free_areas(void)
global_page_state(NR_SLAB_UNRECLAIMABLE),
global_page_state(NR_FILE_MAPPED),
global_page_state(NR_PAGETABLE),
- global_page_state(NR_BOUNCE));
+ global_page_state(NR_BOUNCE),
+ global_page_state(NR_KERNEL_STACK));

for_each_populated_zone(zone) {
int i;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 138bed5..ceda39b 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -639,6 +639,7 @@ static const char * const vmstat_text[] = {
"nr_slab_reclaimable",
"nr_slab_unreclaimable",
"nr_page_table_pages",
+ "nr_kernel_stack",
"nr_unstable",
"nr_bounce",
"nr_vmscan_write",
--
1.6.0.GIT




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