On Thu, 25 Oct 2012 00:04:46 +0200 "Rafael J. Wysocki" [off-list ref] wrote:

On Wednesday 24 of October 2012 14:13:03 Andrew Morton wrote:

quoted

On Wed, 24 Oct 2012 23:06:00 +0200
Borislav Petkov [off-list ref] wrote:

quoted

On Wed, Oct 24, 2012 at 01:48:36PM -0700, Andrew Morton wrote:

quoted

Well who knows. Could be that people's vm *does* suck. Or they have
some particularly peculiar worklosd or requirement[*]. Or their VM
*used* to suck, and the drop_caches is not really needed any more but
it's there in vendor-provided code and they can't practically prevent
it.

I have drop_caches in my suspend-to-disk script so that the hibernation
image is kept at minimum and suspend times are as small as possible.

hm, that sounds smart.

quoted

Would that be a valid use-case?

I'd say so, unless we change the kernel to do that internally.  We do
have the hibernation-specific shrink_all_memory() in the vmscan code. 
We didn't see fit to document _why_ that exists, but IIRC it's there to
create enough free memory for hibernation to be able to successfully
complete, but no more.

That's correct.

Well, my point was: how about the idea of reclaiming clean pagecache
(and inodes, dentries, etc) before hibernation so we read/write less
disk data?

Given that it's so easy to do from the hibernation script, I guess
there's not much point...


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