vmscan: implement swap token trace
This is useful for observing swap token activity.
example output:
zsh-1845 [000] 598.962716: update_swap_token_priority:
mm=ffff88015eaf7700 old_prio=1 new_prio=0
memtoy-1830 [001] 602.033900: update_swap_token_priority:
mm=ffff880037a45880 old_prio=947 new_prio=949
memtoy-1830 [000] 602.041509: update_swap_token_priority:
mm=ffff880037a45880 old_prio=949 new_prio=951
memtoy-1830 [000] 602.051959: update_swap_token_priority:
mm=ffff880037a45880 old_prio=951 new_prio=953
memtoy-1830 [000] 602.052188: update_swap_token_priority:
mm=ffff880037a45880 old_prio=953 new_prio=955
memtoy-1830 [001] 602.427184: put_swap_token:
token_mm=ffff880037a45880
zsh-1789 [000] 602.427281: replace_swap_token:
old_token_mm= (null) old_prio=0 new_token_mm=ffff88015eaf7018
new_prio=2
zsh-1789 [001] 602.433456: update_swap_token_priority:
mm=ffff88015eaf7018 old_prio=2 new_prio=4
zsh-1789 [000] 602.437613: update_swap_token_priority:
mm=ffff88015eaf7018 old_prio=4 new_prio=6
zsh-1789 [000] 602.443924: update_swap_token_priority:
mm=ffff88015eaf7018 old_prio=6 new_prio=8
zsh-1789 [000] 602.451873: update_swap_token_priority:
mm=ffff88015eaf7018 old_prio=8 new_prio=10
zsh-1789 [001] 602.462639: update_swap_token_priority:
mm=ffff88015eaf7018 old_prio=10 new_prio=12
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Rik van Riel<riel@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/thrash.c b/mm/thrash.c
index 6cdf865..17d9e29 100644
--- a/mm/thrash.c
+++ b/mm/thrash.c
@@ -23,6 +23,8 @@
#include <linux/swap.h>
#include <linux/memcontrol.h>
+#include <trace/events/vmscan.h>
+
static DEFINE_SPINLOCK(swap_token_lock);
struct mm_struct *swap_token_mm;
struct mem_cgroup *swap_token_memcg;
@@ -49,6 +51,7 @@
void grab_swap_token(struct mm_struct *mm)
{
int current_interval;
+ unsigned int old_prio = mm->token_priority;
global_faults++;
@@ -63,7 +66,7 @@
if (mm == swap_token_mm) {
mm->token_priority += 2;
- goto out;
+ goto update_priority;
}
if (current_interval < mm->last_interval)
@@ -77,6 +80,9 @@
if (mm->token_priority > swap_token_mm->token_priority)
goto replace_token;
+update_priority:
+ trace_update_swap_token_priority(mm, old_prio);
+
out:
mm->faultstamp = global_faults;
mm->last_interval = current_interval;
@@ -85,6 +91,7 @@
replace_token:
mm->token_priority += 2;
+ trace_replace_swap_token(swap_token_mm, mm);
swap_token_mm = mm;
swap_token_memcg = swap_token_memcg_from_mm(mm);
goto out;
@@ -95,6 +102,7 @@
{
spin_lock(&swap_token_lock);
if (likely(mm == swap_token_mm)) {
+ trace_put_swap_token(swap_token_mm);
swap_token_mm = NULL;
swap_token_memcg = NULL;
}
@@ -118,6 +126,7 @@
if (match_memcg(memcg, swap_token_memcg)) {
spin_lock(&swap_token_lock);
if (match_memcg(memcg, swap_token_memcg)) {
+ trace_disable_swap_token(swap_token_mm);
swap_token_mm = NULL;
swap_token_memcg = NULL;
}