On Tuesday, July 19, 2016 08:36:44 AM Chen Yu wrote:
> test_resume mode is to verify if the snapshot data
> written to swap device can be successfully restored
> to memory. It is useful to ease the debugging process
> on hibernation, since this mode can not only bypass
> the BIOSes/bootloader, but also the system re-initialization.
>
> For example:
> echo test_resume > /sys/power/disk
> echo disk > /sys/power/state
>
> [ 187.306470] PM: Image saving progress: 70%
> [ 187.395298] PM: Image saving progress: 80%
> [ 187.476697] PM: Image saving progress: 90%
> [ 187.554641] PM: Image saving done.
> [ 187.558896] PM: Wrote 594600 kbytes in 0.90 seconds (660.66 MB/s)
> [ 187.566000] PM: S|
> [ 187.589742] PM: Basic memory bitmaps freed
> [ 187.594694] PM: Checking hibernation image
> [ 187.599865] PM: Image signature found, resuming
> [ 187.605209] PM: Loading hibernation image.
> [ 187.665753] PM: Basic memory bitmaps created
> [ 187.691397] PM: Using 3 thread(s) for decompression.
> [ 187.691397] PM: Loading and decompressing image data (148650 pages)...
> [ 187.889719] PM: Image loading progress: 0%
> [ 188.100452] PM: Image loading progress: 10%
> [ 188.244781] PM: Image loading progress: 20%
> [ 189.057305] PM: Image loading done.
> [ 189.068793] PM: Image successfully loaded
>
> Suggested-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> Signed-off-by: Chen Yu <yu.c.c...@intel.com>
> ---
> v5:
> - Introduce a new function to be shared with software_resume().
> v4:
> - Fix some errors and modify the comment for software_resume_unthaw.
> v3:
> - As Pavel mentioned, there was a potential risk in previous
> version that might break the filesystem. According to Rafael's suggestion,
> this version avoids that issue by restoring the pages with user/kernel
> threads kept in frozen. Also updated the patch on top of linux-next.
> ---
> kernel/power/hibernate.c | 61
> ++++++++++++++++++++++++++++++++----------------
> kernel/power/swap.c | 6 +++++
> 2 files changed, 47 insertions(+), 20 deletions(-)
>
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index 5f3523e..73ec63c 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -52,6 +52,7 @@ enum {
> #ifdef CONFIG_SUSPEND
> HIBERNATION_SUSPEND,
> #endif
> + HIBERNATION_TEST_RESUME,
> /* keep last */
> __HIBERNATION_AFTER_LAST
> };
> @@ -647,12 +648,39 @@ static void power_down(void)
> cpu_relax();
> }
>
> +static int load_image_and_restore(void)
> +{
> + int error;
> + unsigned int flags;
> +
> + pr_debug("PM: Loading hibernation image.\n");
> +
> + lock_device_hotplug();
> + error = create_basic_memory_bitmaps();
> + if (error)
> + goto Unlock;
> +
> + error = swsusp_read(&flags);
> + swsusp_close(FMODE_READ);
> + if (!error)
> + hibernation_restore(flags & SF_PLATFORM_MODE);
> +
> + printk(KERN_ERR "PM: Failed to load hibernation image, recovering.\n");
> + swsusp_free();
> + free_basic_memory_bitmaps();
> + Unlock:
> + unlock_device_hotplug();
> +
> + return error;
> +}
> +
> /**
> * hibernate - Carry out system hibernation, including saving the image.
> */
> int hibernate(void)
> {
> int error, nr_calls = 0;
> + bool snapshot_test = false;
>
> if (!hibernation_available()) {
> pr_debug("PM: Hibernation not available.\n");
> @@ -704,7 +732,9 @@ int hibernate(void)
> pr_debug("PM: writing image.\n");
> error = swsusp_write(flags);
> swsusp_free();
> - if (!error)
> + if (hibernation_mode == HIBERNATION_TEST_RESUME)
> + snapshot_test = true;
> + if (!error && !snapshot_test)
The above change isn't correct IMO.
If swsusp_write() returns an error, snapshot_test shouldn't be set (that
basically means "no image", so nothing to test).
So this code should look like
if (!error) {
if (hibernation_mode == HIBERNATION_TEST_RESUME)
snapshot_test = true;
else
power_down();
}
The rest of the patch looks OK to me.
Thanks,
Rafael
