Purge caches in memory before suspending

yozhhh · 11-23-2006, 05:02 PM

I'm using linux on my laptop having 1Gb memory. Each time i start "suspend to disk" the kernel stores the actual memory contents to swap partition. I discovered today that the caches in memory are also written to the swap!

Currently, the memory usage is:

Code:

# free -m
             total       used       free     shared    buffers     cached
Mem:          1010        488        522          0         17        348
-/+ buffers/cache:        123        887
Swap:         1535          0       1535

The caches use 348 Mb of memory. Each time i suspend my laptop this content is written to disk and then read from disk into memory when i switch my laptop on (?). It takes very much time and i don't need it, definitely!

Is there a way to clean the caches before starting suspend?

JZL240I-U · 12-01-2006, 02:48 AM

This is a wild guess: try "sync" and compare the "free -m" results. Just maybeee...

blackhole54 · 12-01-2006, 09:18 AM

Quote:

Originally Posted by JZL240I-U

This is a wild guess: try "sync" and compare the "free -m" results. Just maybeee...

I think "sync" just flushes stuff to the disk but doesn't alter memory allocated to cache or buffer (but it never hurts to try.)

I was monitoring this thread to see if anybody came up with something. The kernel is just following the philosophy of "unused memory is wasted memory." Perhaps the issue should be thought of as being with the suspend routines. That either they shouldn't save cache and buffer to disk, or this should be an option. Maybe it is already that way. If not, maybe it should be proposed on the KML.

JZL240I-U · 12-01-2006, 09:34 AM

Well it is a wild guess. As I'm not in front of a linux system perhaps one could try "man *mem*" or "man *buff*"