Messages in this thread | | | Date | Mon, 22 Aug 2022 16:21:25 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH 3/3] dma-pool: limit DMA and DMA32 zone size pools |
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On Mon 22-08-22 14:27:59, Christoph Hellwig wrote: > On Mon, Aug 22, 2022 at 02:09:13PM +0200, Michal Hocko wrote: > > OK, so you are worried about configurations that lack ZONE_DMA32 because > > that memory range is covered by ZONE_DMA? I thought though simply do not > > have CONFIG_ZONE_DMA32. Or am I wrong here? > > Zones can disappear when they are empty. Normally that affects > ZONE_NORMAL and ZONE_HIGHMEM, but it can also happen to ZONE_DMA32 > when there is not enough memory.
Correct but that is essentially the same problem as ZONE_DMA becoming empty. Or maybe I am just completely missing what you are trying to say/ask?
My whole point was that if those zones are configured and you cannot pre-allocate the pool then this can be either a result of OOM on that zone or zone completely empty. In either case the pool would be empty and if that is something worth bothering^Wnotifying an admin about then better provide something useful rather than over messaging for one case and be silent about the other. See my point?
-- Michal Hocko SUSE Labs
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