On Mon, Jan 25, 2016 at 04:06:40PM -0800, Dan Williams wrote: > It appears devices requiring ZONE_DMA are still prevalent (see link > below). For this reason the proposal to require turning off ZONE_DMA to > enable ZONE_DEVICE is untenable in the short term. We want a single > kernel image to be able to support legacy devices as well as next > generation persistent memory platforms. > > Towards this end, alias ZONE_DMA and ZONE_DEVICE to work around needing > to maintain a unique zone number for ZONE_DEVICE. Record the geometry > of ZONE_DMA at init (->init_spanned_pages) and use that information in > is_zone_device_page() to differentiate pages allocated via > devm_memremap_pages() vs true ZONE_DMA pages. Otherwise, use the > simpler definition of is_zone_device_page() when ZONE_DMA is turned off. > > Note that this also teaches the memory hot remove path that the zone may > not have sections for all pfn spans (->zone_dyn_start_pfn). > > A user visible implication of this change is potentially an unexpectedly > high "spanned" value in /proc/zoneinfo for the DMA zone. > > Cc: H. Peter Anvin <hpa@xxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxx> > Cc: Mel Gorman <mgorman@xxxxxxx> > Cc: Jerome Glisse <j.glisse@xxxxxxxxx> > Cc: Christoph Hellwig <hch@xxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > Link: https://bugzilla.kernel.org/show_bug.cgi?id=110931 > Fixes: 033fbae988fc ("mm: ZONE_DEVICE for "device memory"") > Reported-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> It should actually be Reported-by: Mark <markk@xxxxxxxxxxx> Hi Mark, Can you please test this patch available at https://patchwork.kernel.org/patch/8116991/ in your setup.. regards sudip -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>