Re: [PATCH 3/4] PM/Hibernate: Use memory allocations to free memory (rev. 2)

Pavel Machek
2009-05-03T09:36:59Z

Hi!

> > Remove the shrinking of memory from the suspend-to-RAM code, where it is
> > not really necessary.
>
> Hmm. Shouldn't we do this _regardless_?
>
> IOW, shouldn't this be a totally separate patch? It seems to be left-over
> from when we shared the same code-paths, and before the split of the STR
> and hibernate code?
>
> IOW, shouldn't the very _first_ patch just be this part? That code doesn't
> make any sense anyway (that FREE_PAGE_NUMBER really _is_ totally
> arbitrary).
>
> This part seems to be totally independent of all the other parts in your
> patch-series. No?

I'm not sure this one is a good idea: drivers will need to allocate
memory during suspend/resume, and when processes are frozen/disk
driver is suspended, normal memory management will no longer work.

So, freeing 4M of memory before starting suspend seems like a good
idea. That way those small alocations will not fail.
Pavel

> @@ -188,9 +188,6 @@ static void suspend_test_finish(const char *label)
>
> #endif
>
> -/* This is just an arbitrary number */
> -#define FREE_PAGE_NUMBER (100)
> -
> static struct platform_suspend_ops *suspend_ops;
>
> /**
> @@ -241,24 +238,10 @@ static int suspend_prepare(void)
> if (error)
> goto Finish;
>
> - if (suspend_freeze_processes()) {
> - error = -EAGAIN;
> - goto Thaw;
> - }
> -
> - free_pages = global_page_state(NR_FREE_PAGES);
> - if (free_pages < FREE_PAGE_NUMBER) {
> - pr_debug("PM: free some memory\n");
> - shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
> - if (nr_free_pages() < FREE_PAGE_NUMBER) {
> - error = -ENOMEM;
> - printk(KERN_ERR "PM: No enough memory\n");
> - }
> - }
> + error = suspend_freeze_processes();
> if (!error)
> return 0;
>
> - Thaw:
> suspend_thaw_processes();
> usermodehelper_enable();
> Finish:

--
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