lowmemorykiller: trace kill events.

Allows for capturing lmk kill events and
their rationale.

Change-Id: Ibe215db5bb9806fc550c72c0b9832c85cbd56bf6
Signed-off-by: Martijn Coenen <maco@google.com>

diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c
index 8a23d37428bbcd08722e75a2ac0633d4b470fb84..c62d951ada50792fab5f795e7b6479804b110c75 100644 (file)
--- a/drivers/staging/android/lowmemorykiller.c
+++ b/drivers/staging/android/lowmemorykiller.c
@@ -43,6 +43,9 @@
 #include <linux/profile.h>
 #include <linux/notifier.h>
 
+#define CREATE_TRACE_POINTS
+#include "trace/lowmemorykiller.h"
+
 static uint32_t lowmem_debug_level = 1;
 static short lowmem_adj[6] = {
        0,
@@ -168,6 +171,10 @@ static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc)
                if (selected->mm)
                        mark_oom_victim(selected);
                task_unlock(selected);
+               long cache_size = other_file * (long)(PAGE_SIZE / 1024);
+               long cache_limit = minfree * (long)(PAGE_SIZE / 1024);
+               long free = other_free * (long)(PAGE_SIZE / 1024);
+               trace_lowmemory_kill(selected, cache_size, cache_limit, free);
                lowmem_print(1, "Killing '%s' (%d), adj %hd,\n" \
                                "   to free %ldkB on behalf of '%s' (%d) because\n" \
                                "   cache %ldkB is below limit %ldkB for oom_score_adj %hd\n" \
@@ -176,10 +183,9 @@ static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc)
                             selected_oom_score_adj,
                             selected_tasksize * (long)(PAGE_SIZE / 1024),
                             current->comm, current->pid,
-                            other_file * (long)(PAGE_SIZE / 1024),
-                            minfree * (long)(PAGE_SIZE / 1024),
+                            cache_size, cache_limit,
                             min_score_adj,
-                            other_free * (long)(PAGE_SIZE / 1024));
+                            free);
                lowmem_deathpending_timeout = jiffies + HZ;
                rem += selected_tasksize;
        }

diff --git a/drivers/staging/android/trace/lowmemorykiller.h b/drivers/staging/android/trace/lowmemorykiller.h
new file mode 100644 (file)
index 0000000..f43d3fa
--- /dev/null
+++ b/drivers/staging/android/trace/lowmemorykiller.h
@@ -0,0 +1,41 @@
+#undef TRACE_SYSTEM
+#define TRACE_INCLUDE_PATH ../../drivers/staging/android/trace
+#define TRACE_SYSTEM lowmemorykiller
+
+#if !defined(_TRACE_LOWMEMORYKILLER_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_LOWMEMORYKILLER_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(lowmemory_kill,
+       TP_PROTO(struct task_struct *killed_task, long cache_size, \
+                long cache_limit, long free),
+
+       TP_ARGS(killed_task, cache_size, cache_limit, free),
+
+       TP_STRUCT__entry(
+                       __array(char, comm, TASK_COMM_LEN)
+                       __field(pid_t, pid)
+                       __field(long, pagecache_size)
+                       __field(long, pagecache_limit)
+                       __field(long, free)
+       ),
+
+       TP_fast_assign(
+                       memcpy(__entry->comm, killed_task->comm, TASK_COMM_LEN);
+                       __entry->pid = killed_task->pid;
+                       __entry->pagecache_size = cache_size;
+                       __entry->pagecache_limit = cache_limit;
+                       __entry->free = free;
+       ),
+
+       TP_printk("%s (%d), page cache %ldkB (limit %ldkB), free %ldKb",
+               __entry->comm, __entry->pid, __entry->pagecache_size,
+               __entry->pagecache_limit, __entry->free)
+);
+
+
+#endif /* if !defined(_TRACE_LOWMEMORYKILLER_H) || defined(TRACE_HEADER_MULTI_READ) */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>