On Thu, Jun 06, 2024 at 10:28:11AM -0700, Isaac J. Manjarres wrote: > From: Manish Varma <varmam@xxxxxxxxxx> > > 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 > "epollN:P" (instead of just "eventpoll"), where N is a unique ID token, > and P is the PID of the creating process. > 2) individual per-underlying-file descriptor 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. > > Co-developed-by: Kelly Rossmoyer <krossmo@xxxxxxxxxx> > Signed-off-by: Kelly Rossmoyer <krossmo@xxxxxxxxxx> > Signed-off-by: Manish Varma <varmam@xxxxxxxxxx> > Co-developed-by: Isaac J. Manjarres <isaacmanjarres@xxxxxxxxxx> > Signed-off-by: Isaac J. Manjarres <isaacmanjarres@xxxxxxxxxx> > --- > drivers/base/power/wakeup.c | 12 +++++++++--- > fs/eventpoll.c | 11 +++++++++-- > include/linux/pm_wakeup.h | 8 ++++---- > 3 files changed, 22 insertions(+), 9 deletions(-) > > v1 -> v2: > - Renamed instance count to wakesource_create_id to better describe > its purpose. > - Changed the wakeup source naming convention for wakeup sources > created by eventpoll to avoid changing the timerfd names. > - Used the PID of the process instead of the process name for the > sake of uniqueness when creating wakeup sources. > > v2 -> v3: > - Changed wakeup_source_register() to take in a format string > and arguments to avoid duplicating code to construct wakeup > source names. > - Moved the definition of wakesource_create_id so that it is > always defined to fix an compilation error. > > v3 -> v4: > - Changed the naming convention for the top-level epoll wakeup > sources to include an ID for uniqueness. This is needed in > cases where a process is using two epoll fds. > - Edited commit log to reflect new changes and add new tags. > > v4 -> v5: > - Added the format attribute to the wakeup_source_register() > function to address a warning from the kernel test robot: > https://lore.kernel.org/all/202406050504.UvdlPAQ0-lkp@xxxxxxxxx/ > > diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c > index 752b417e8129..04a808607b62 100644 > --- a/drivers/base/power/wakeup.c > +++ b/drivers/base/power/wakeup.c > @@ -209,13 +209,19 @@ 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) > +__printf(2, 3) struct wakeup_source *wakeup_source_register(struct device *dev, > + 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 f53ca4f7fced..941df15208a4 100644 > --- a/fs/eventpoll.c > +++ b/fs/eventpoll.c > @@ -338,6 +338,7 @@ static void __init epoll_sysctls_init(void) > #define epoll_sysctls_init() do { } while (0) > #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) > @@ -1545,15 +1546,21 @@ 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"); > + id = atomic_inc_return(&wakesource_create_id); > + epi->ep->ws = wakeup_source_register(NULL, "epoll:%d:%d", id, 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 76cd1f9f1365..1fb6dca981c2 100644 > --- a/include/linux/pm_wakeup.h > +++ b/include/linux/pm_wakeup.h > @@ -99,8 +99,8 @@ extern struct wakeup_source *wakeup_source_create(const char *name); > 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); > +extern __printf(2, 3) struct wakeup_source *wakeup_source_register(struct device *dev, > + 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); > @@ -140,8 +140,8 @@ 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) > +static inline __printf(2, 3) struct wakeup_source *wakeup_source_register(struct device *dev, > + const char *fmt, ...) > { > return NULL; > } > -- > 2.45.2.505.gda0bf45e8d-goog Hello, Just following up to see if there are comments or concerns with this patch? Thanks, Isaac
