On Fri 2019-02-22 23:49:04, Harry Pan wrote:
> This patch gives the reader an intuitive metric of the time cost by
> the kernel issuing a filesystem sync during system sleep; although
> developer can guess by the timestamp of next log or enable the ftrace
> power event for manual calculation, this manner is easier to read and
> benefits the automatic script.
>
> v2: simplify the variables, apply the simplest form of ktime API.
> v3: reduce conditional compilation, rectify profiling in better syntax
> v4: avoid interposition, profile on hibernation, rectify printk format
> v5: introduce sync helper shared by suspend, hibernate, and snapshot
>
> Signed-off-by: Harry Pan <harry....@intel.com>
> ---
> include/linux/suspend.h | 3 +++
> kernel/power/hibernate.c | 5 +----
> kernel/power/main.c | 15 +++++++++++++++
> kernel/power/suspend.c | 13 +++++--------
> kernel/power/user.c | 5 +----
> 5 files changed, 25 insertions(+), 16 deletions(-)
>
> diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> index 3f529ad9a9d2..6b3ea9ea6a9e 100644
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -425,6 +425,7 @@ void restore_processor_state(void);
> /* kernel/power/main.c */
> extern int register_pm_notifier(struct notifier_block *nb);
> extern int unregister_pm_notifier(struct notifier_block *nb);
> +extern void ksys_sync_helper(void);
>
> #define pm_notifier(fn, pri) { \
> static struct notifier_block fn##_nb = \
> @@ -462,6 +463,8 @@ static inline int unregister_pm_notifier(struct
> notifier_block *nb)
> return 0;
> }
>
> +static inline void ksys_sync_helper(void) {}
> +
> #define pm_notifier(fn, pri) do { (void)(fn); } while (0)
>
> static inline bool pm_wakeup_pending(void) { return false; }
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index abef759de7c8..cc105ecd9c07 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -14,7 +14,6 @@
>
> #include <linux/export.h>
> #include <linux/suspend.h>
> -#include <linux/syscalls.h>
> #include <linux/reboot.h>
> #include <linux/string.h>
> #include <linux/device.h>
> @@ -709,9 +708,7 @@ int hibernate(void)
> goto Exit;
> }
>
> - pr_info("Syncing filesystems ... \n");
> - ksys_sync();
> - pr_info("done.\n");
> + ksys_sync_helper();
>
> error = freeze_processes();
> if (error)
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 35b50823d83b..a08dcc743f31 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -16,6 +16,7 @@
> #include <linux/debugfs.h>
> #include <linux/seq_file.h>
> #include <linux/suspend.h>
> +#include <linux/syscalls.h>
>
> #include "power.h"
>
> @@ -51,6 +52,20 @@ void unlock_system_sleep(void)
> }
> EXPORT_SYMBOL_GPL(unlock_system_sleep);
>
> +void ksys_sync_helper(void)
> +{
> + ktime_t start;
> + s64 elapsed_msecs;
> +
> + start = ktime_get();
> + ksys_sync();
> + elapsed_msecs = ktime_to_ms(ktime_sub(ktime_get(), start));
> + pr_info("Filesystems sync: %lld.%03lld seconds\n",
> + elapsed_msecs / MSEC_PER_SEC,
> + elapsed_msecs % MSEC_PER_SEC);
> +}
Sharing code is fine. Changing message, remove partial print before
long operation is not.
Adding timing is not, either. There are other ways to get that info.
NAK.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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