On Friday 15 May 2009, Pavel Machek wrote: > On Thu 2009-05-14 19:52:20, Rafael J. Wysocki wrote: > > On Thursday 14 May 2009, Pavel Machek wrote: > > > Hi! > > > > > > > Since the hibernation code is now going to use allocations of memory > > > > to make enough room for the image, it can also use the page frames > > > > allocated at this stage as image page frames. The low-level > > > > hibernation code needs to be rearranged for this purpose, but it > > > > allows us to avoid freeing a great number of pages and allocating > > > > these same pages once again later, so it generally is worth doing. > > > > > > > > [rev. 2: Take highmem into account correctly.] > > > > > > I don't get it. What is advantage of this patch? It makes the code > > > more complex... Is it supposed to be faster? > > > > Yes, in some test cases it is reported to be faster (along with [4/6], > > actually). > > > > Besides, we'd like to get rid of shrink_all_memory() eventually and it is a > > step in this direction. > > Ok, but maybe we should wait with applying this until we have patches > that actually get us rid of shrink_all_memory? Well, the $subject patch is only an optimization of top of [4/6] that you've just acked. ;-) In fact [4/6] changes the approach to the memory shrinking and the $subject one is only to avoid freeing all of the memory we've allocated and allocating it once again later. > Maybe it will not be feasible for speed reasons after all, or something... At least it allows us to drop shrink_all_memory() easily for the sake of experimentation (it's sufficient to comment out just one line of code for this purpose). Besides, after this patchset shrink_all_memory() is _only_ needed for performance, so it should be possible to get rid of it relatively quckly. Thanks, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
