[PATCH 2/3] vmscan: implement swap token trace

From: KOSAKI Motohiro
Date: Fri May 13 2011 - 07:39:18 EST


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@xxxxxxxxxxxxxx>
---
include/trace/events/vmscan.h | 77 +++++++++++++++++++++++++++++++++++++++++
mm/thrash.c | 11 +++++-
2 files changed, 87 insertions(+), 1 deletions(-)

diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index ea422aa..1798e0c 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -6,6 +6,8 @@

#include <linux/types.h>
#include <linux/tracepoint.h>
+#include <linux/mm.h>
+#include <linux/memcontrol.h>
#include "gfpflags.h"

#define RECLAIM_WB_ANON 0x0001u
@@ -310,6 +312,81 @@ TRACE_EVENT(mm_vmscan_lru_shrink_inactive,
show_reclaim_flags(__entry->reclaim_flags))
);

+TRACE_EVENT(replace_swap_token,
+ TP_PROTO(struct mm_struct *old_mm,
+ struct mm_struct *new_mm),
+
+ TP_ARGS(old_mm, new_mm),
+
+ TP_STRUCT__entry(
+ __field(struct mm_struct*, old_mm)
+ __field(unsigned int, old_prio)
+ __field(struct mm_struct*, new_mm)
+ __field(unsigned int, new_prio)
+ ),
+
+ TP_fast_assign(
+ __entry->old_mm = old_mm;
+ __entry->old_prio = old_mm ? old_mm->token_priority : 0;
+ __entry->new_mm = new_mm;
+ __entry->new_prio = new_mm->token_priority;
+ ),
+
+ TP_printk("old_token_mm=%p old_prio=%u new_token_mm=%p new_prio=%u",
+ __entry->old_mm, __entry->old_prio,
+ __entry->new_mm, __entry->new_prio)
+);
+
+DECLARE_EVENT_CLASS(put_swap_token_template,
+ TP_PROTO(struct mm_struct *swap_token_mm),
+
+ TP_ARGS(swap_token_mm),
+
+ TP_STRUCT__entry(
+ __field(struct mm_struct*, swap_token_mm)
+ ),
+
+ TP_fast_assign(
+ __entry->swap_token_mm = swap_token_mm;
+ ),
+
+ TP_printk("token_mm=%p", __entry->swap_token_mm)
+);
+
+DEFINE_EVENT(put_swap_token_template, put_swap_token,
+ TP_PROTO(struct mm_struct *swap_token_mm),
+ TP_ARGS(swap_token_mm)
+);
+
+DEFINE_EVENT_CONDITION(put_swap_token_template, disable_swap_token,
+ TP_PROTO(struct mm_struct *swap_token_mm),
+ TP_ARGS(swap_token_mm),
+ TP_CONDITION(swap_token_mm != NULL)
+);
+
+TRACE_EVENT_CONDITION(update_swap_token_priority,
+ TP_PROTO(struct mm_struct *mm,
+ unsigned int old_prio),
+
+ TP_ARGS(mm, old_prio),
+
+ TP_CONDITION(mm->token_priority != old_prio),
+
+ TP_STRUCT__entry(
+ __field(struct mm_struct*, mm)
+ __field(unsigned int, old_prio)
+ __field(unsigned int, new_prio)
+ ),
+
+ TP_fast_assign(
+ __entry->mm = mm;
+ __entry->old_prio = old_prio;
+ __entry->new_prio = mm->token_priority;
+ ),
+
+ TP_printk("mm=%p old_prio=%u new_prio=%u",
+ __entry->mm, __entry->old_prio, __entry->new_prio)
+);

#endif /* _TRACE_VMSCAN_H */

diff --git a/mm/thrash.c b/mm/thrash.c
index 32c07fd..14c6c9f 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;
@@ -31,6 +33,7 @@ static unsigned int global_faults;
void grab_swap_token(struct mm_struct *mm)
{
int current_interval;
+ unsigned int old_prio = mm->token_priority;
struct mem_cgroup *memcg;

global_faults++;
@@ -46,7 +49,7 @@ void grab_swap_token(struct mm_struct *mm)

if (mm == swap_token_mm) {
mm->token_priority += 2;
- goto out;
+ goto update_priority;
}

if (current_interval < mm->last_interval)
@@ -60,6 +63,9 @@ void grab_swap_token(struct mm_struct *mm)
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;
@@ -71,6 +77,7 @@ replace_token:
memcg = try_get_mem_cgroup_from_mm(mm);
if (memcg)
css_put(mem_cgroup_css(memcg));
+ trace_replace_swap_token(swap_token_mm, mm);
swap_token_mm = mm;
swap_token_memcg = memcg;
goto out;
@@ -81,6 +88,7 @@ void __put_swap_token(struct mm_struct *mm)
{
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;
}
@@ -104,6 +112,7 @@ void disable_swap_token(struct mem_cgroup *memcg)
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;
}
--
1.7.3.1



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