timerfd doesn't create any wakelocks, but eventpoll can. When it does,
it names them after the underlying file descriptor, and since all
timerfd file descriptors are named "[timerfd]" (which saves memory on
systems like desktops with potentially many timerfd instances), all
wakesources created as a result of using the eventpoll-on-timerfd idiom
are called... "[timerfd]".
However, it becomes impossible to tell which "[timerfd]" wakesource is
affliated with which process and hence troubleshooting is difficult.
This change addresses this problem by changing the way eventpoll
wakesources are named:
1) the top-level per-process eventpoll wakesource is now named "epoll:P"
(instead of just "eventpoll"), where P, is the PID of the creating
process.
2) individual per-underlying-filedescriptor eventpoll wakesources are
now named "epollitemN:P.F", where N is a unique ID token and P is PID
of the creating process and F is the name of the underlying file
descriptor.
All together that should be splitted up into a change to eventpoll and
timerfd (or other file descriptors).
Reported-by: kernel test robot <l...@intel.com>
Co-developed-by: Kelly Rossmoyer <kros...@google.com>
Signed-off-by: Kelly Rossmoyer <kros...@google.com>
Signed-off-by: Manish Varma <var...@google.com>
---
drivers/base/power/wakeup.c | 10 ++++++++--
fs/eventpoll.c | 10 ++++++++--
include/linux/pm_wakeup.h | 4 ++--
3 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 01057f640233..3628536c67a5 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -216,13 +216,19 @@ EXPORT_SYMBOL_GPL(wakeup_source_remove);
/**
* wakeup_source_register - Create wakeup source and add it to the list.
* @dev: Device this wakeup source is associated with (or NULL if virtual).
- * @name: Name of the wakeup source to register.
+ * @fmt: format string for the wakeup source name
*/
struct wakeup_source *wakeup_source_register(struct device *dev,
- const char *name)
+ const char *fmt, ...)
{
struct wakeup_source *ws;
int ret;
+ char name[128];
+ va_list args;
+
+ va_start(args, fmt);
+ vsnprintf(name, sizeof(name), fmt, args);
+ va_end(args);
ws = wakeup_source_create(name);
if (ws) {
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 7df8c0fa462b..7c35987a8887 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -312,6 +312,7 @@ struct ctl_table epoll_table[] = {
};
#endif /* CONFIG_SYSCTL */
+static atomic_t wakesource_create_id = ATOMIC_INIT(0);
static const struct file_operations eventpoll_fops;
static inline int is_file_epoll(struct file *f)
@@ -1451,15 +1452,20 @@ static int ep_create_wakeup_source(struct epitem *epi)
{
struct name_snapshot n;
struct wakeup_source *ws;
+ pid_t task_pid;
+ int id;
+
+ task_pid = task_pid_nr(current);
if (!epi->ep->ws) {
- epi->ep->ws = wakeup_source_register(NULL, "eventpoll");
+ epi->ep->ws = wakeup_source_register(NULL, "epoll:%d",
task_pid);
if (!epi->ep->ws)
return -ENOMEM;
}
+ id = atomic_inc_return(&wakesource_create_id);
take_dentry_name_snapshot(&n, epi->ffd.file->f_path.dentry);
- ws = wakeup_source_register(NULL, n.name.name);
+ ws = wakeup_source_register(NULL, "epollitem%d:%d.%s", id, task_pid,
n.name.name);
release_dentry_name_snapshot(&n);
if (!ws)
diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index aa3da6611533..cb91c84f6f08 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -95,7 +95,7 @@ extern void wakeup_source_destroy(struct wakeup_source *ws);
extern void wakeup_source_add(struct wakeup_source *ws);
extern void wakeup_source_remove(struct wakeup_source *ws);
extern struct wakeup_source *wakeup_source_register(struct device *dev,
- const char *name);
+ const char *fmt, ...);
extern void wakeup_source_unregister(struct wakeup_source *ws);
extern int wakeup_sources_read_lock(void);
extern void wakeup_sources_read_unlock(int idx);
@@ -137,7 +137,7 @@ static inline void wakeup_source_add(struct wakeup_source
*ws) {}
static inline void wakeup_source_remove(struct wakeup_source *ws) {}
static inline struct wakeup_source *wakeup_source_register(struct device *dev,
- const char *name)
+ const char *fmt, ...)
{
return NULL;
}
--
2.31.0.208.g409f899ff0-goog
