Messages in this thread | | | Date | Sat, 10 Dec 2005 17:06:41 +0100 | From | Pavel Machek <> | Subject | Re: [RFC/RFT] swsusp: image size tunable (was: Re: [PATCH][mm] swsusp: limit image size) |
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Hi!
> > The tunable may be useful to people who'd like to achieve the > > maximum efficiency of suspend/resume and it would be a nice > > feature to have, I think, but let's say we'll try to implement it > > in the future, if still needed/wanted. > > Actually the tunable turned out to be quite easy to implement and I think > I'll need it for userspace swsusp (the suspend-handling userspace > process will need to tell the kernel how much space there is for the > image).
Looks mostly okay to me, small comments below.
> Index: linux-2.6.15-rc5-mm1/kernel/power/disk.c > =================================================================== > --- linux-2.6.15-rc5-mm1.orig/kernel/power/disk.c 2005-12-10 13:12:18.000000000 +0100 > +++ linux-2.6.15-rc5-mm1/kernel/power/disk.c 2005-12-10 13:20:38.000000000 +0100 > @@ -367,9 +367,34 @@ > > power_attr(resume); > > +static ssize_t image_size_show(struct subsystem * subsys, char *buf) > +{ > + return sprintf(buf, "%u\n", image_size); > +} > + > +static ssize_t image_size_store(struct subsystem * subsys, const char * buf, size_t n) > +{ > + int len; > + char *p; > + unsigned int size; > + > + p = memchr(buf, '\n', n); > + len = p ? p - buf : n;
len and p are unused.
> + if (sscanf(buf, "%u", &size) == 1) { > + image_size = size < MAX_IMAGE_SIZE ? size : MAX_IMAGE_SIZE; > + return n;
Why the limit? We may want to allow very big images when someone wants "as similar to suspended system as possible".
> Index: linux-2.6.15-rc5-mm1/kernel/power/power.h > =================================================================== > --- linux-2.6.15-rc5-mm1.orig/kernel/power/power.h 2005-12-10 13:12:18.000000000 +0100 > +++ linux-2.6.15-rc5-mm1/kernel/power/power.h 2005-12-10 13:20:46.000000000 +0100 > @@ -53,10 +53,12 @@ > extern struct pbe *pagedir_nosave; > > /* > - * Preferred image size in MB (set it to zero to get the smallest > + * Maximum image size in MB (set it to zero to get the smallest > * image possible) > */
In fact this is not maximum. If more than 500MB can't be freed, well, it will not be freed. Very improbable, but possible.
> -#define IMAGE_SIZE 500 > +#define MAX_IMAGE_SIZE 500 > +
With runtime configuration, we should not need additional compile-time config. OTOH /proc tunables should have descritption in Documentation/.
Pavel -- Thanks, Sharp! - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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