Messages in this thread | | | Date | Fri, 13 Sep 2002 14:30:47 -0700 | From | Andrew Morton <> | Subject | Re: Good way to free as much memory as possible under 2.5.34? |
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Rik van Riel wrote: > > On Fri, 13 Sep 2002, Pavel Machek wrote: > > > /* > > * Try to free as much memory as possible, but do not OOM-kill anyone > > * > > * Notice: all userland should be stopped at this point, or livelock > > is possible. > > */ > > > > This worked before -rmap came in, but it does not free anything > > now. What needs to be done to fix it? > > Actually, it still worked when -rmap came in, but it stopped working > when the LRU lists were made to be per-zone...
hmm, I missed that. Yes, the zone balancing in try_to_free_pages() will see that all zones are above ->pages_high and will just return.
> > static void free_some_memory(void) > > { > > printk("Freeing memory: "); > > while > > (try_to_free_pages(&contig_page_data.node_zones[ZONE_HIGHMEM], GFP_KSWAPD, 0)) > > printk("."); > > printk("|\n"); > > } > > Why don't you just allocate memory ?
That would work.
> To prevent the OOM kill you can just check for a variable > in the OOM slow path. No need to rely on any particular > behaviour of the VM. >
Sure.
I'm not sure why swsusp needs "half of memory to be free"? What's the story there?
I'd recommend that you sit in a loop, allocating pages with an allocation mode of
__GFP_HIGHMEM | __GFP_WAIT
This will give you all the easily-reclaimable pages in the machine, without trashing the page reserves (no __GFP_HIGH).
String all the pages together via page->list and when you have "enough", free them all again. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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