Messages in this thread | | | Date | Sun, 3 Nov 2002 12:52:06 -0800 | From | William Lee Irwin III <> | Subject | Re: Hot/cold allocation -- swsusp can not handle hot pages |
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On Sun, Nov 03, 2002 at 09:08:09PM +0100, Pavel Machek wrote: > "big-picture" should be in Documentation/swsusp.txt... > *Should* be :-(. I need to copy all used memory, to make sure my > snapshot is atomic. > Copying works by looking at what is allocated, counting needed pages, > allocating 'directory' for them, allocating memory for copies, and > actually copying. > When I suddenly find I have less data to copy than I thought, it > screws up the code.
Why don't we just mark PG_nosave in page->flags and stuff order in page->index (or elsewhere) for you and then you can safely walk the zone->zone_mem_map? A single pass of marking up-front should be a bit quicker than searching the lists for a list head at every page, and also something more maintainable/comprehensible: we can basically know what we're dealing with and do a kind of "shutdown" of the stuff for you:
static void empty_pageset(struct zone *zone, struct per_cpu_pages *pcp) { pcp->batch = pcp->low = pcp->high = 1; pcp->count -= free_pages_bulk(zone, pcp->batch, &pcp->list, 0); }
static void empty_cpu_pages(void *unused) { struct zone *zone; unsigned long flags; int cpu;
cpu = get_cpu(); local_irq_save(flags);
for_each_zone(zone) { empty_pcp(zone, &zone->pageset[cpu].pcp[0]); empty_pcp(zone, &zone->pageset[cpu].pcp[1]); }
local_irq_restore(flags); put_cpu(); }
static void shootdown_per_cpu_pages(void) { smp_call_function(empty_cpu_pages, NULL, 0, 1); empty_cpu_pages(NULL); }
void suspend_mark_free_pages(void) { struct zone *zone; struct free_area *area; struct page *page; unsigned long flags; int order;
shootdown_per_cpu_pages();
for_each_zone(zone) { spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; ++order) { area = &zone->free_area[order]; list_for_each_entry(page, &area->free_list, list) { SetPageNosave(page); /* if ->index clashes, use flag bits */ page->index = order; } } spin_unlock_irqrestore(&zone->lock, flags); } }
Then you can just do
if (PageNosave(page)) pfn += 1 << page->index;
in kernel/suspend.c and everybody's happy, no?
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