Re: [RFC][PATCH -mm 2/5] swsusp: Use memory bitmaps during resume

Pavel Machek
2006-08-09T11:49:42Z

Hi!

> Make swsusp use memory bitmaps to store its internal information during the
> resume phase of the suspend-resume cycle.
>
> If the pfns of saveable pages are saved during the suspend phase instead of
> the kernel virtual addresses of these pages, we can use them during the resume
> phase directly to set the corresponding bits in a memory bitmap. Then, this
> bitmap is used to mark the page frames corresponding to the pages that were
> saveable before the suspend (aka "unsafe" page frames).
>
> Next, we allocate as many page frames as needed to store the entire suspend
> image and make sure that there will be some extra free "safe" page frames for
> the list of PBEs constructed later. Subsequently, the image is loaded and,
> if possible, the data loaded from it are written into their "original" page frames
> (ie. the ones they had occupied before the suspend). The image data that
> cannot be written into their "original" page frames are loaded into "safe" page
> frames and their "original" kernel virtual addresses, as well as the addresses
> of the "safe" pages containing their copies, are stored in a list of PBEs.
> Finally, the list of PBEs is used to copy the remaining image data into their
> "original" page frames (this is done atomically, by the architecture-dependent
> parts of swsusp).
>
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

ACK. If we get bitmap code we may as well use it. Should wait in -mm
for a while.

> @@ -53,7 +40,7 @@ static inline void pm_restore_console(vo
> static inline int software_suspend(void)
> {
> printk("Warning: fake suspend called\n");
> - return -EPERM;
> + return -ENOSYS;
> }
> #endif /* CONFIG_PM */
>

Heh, yes, it is right.. it is also totally unrelated and changes
userland interface ;-)))... which is probably okay here. But separate
would be nice.
Pavel