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

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

> 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.

I forgot to insert most important one line ;-)

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

> ---
>  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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