From: Sergey Dyasli Date: Wed, 9 Jan 2019 14:45:14 +0000 (+0100) Subject: mm/page_alloc: fix MEMF_no_dma allocations for single NUMA X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~2665 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=5ac2dddb173b69be259ce4b259e73f971a4816c1;p=xen.git mm/page_alloc: fix MEMF_no_dma allocations for single NUMA Currently dma_bitsize is zero by default on single NUMA node machines. This makes all alloc_domheap_pages() calls with MEMF_no_dma return NULL. There is only 1 user of MEMF_no_dma: dom0_memflags, which are used during memory allocation for Dom0. Failing allocation with default dom0_memflags is especially severe for the PV Dom0 case: it makes alloc_chunk() to use suboptimal 2MB allocation algorithm with a search for higher memory addresses. This can lead to the NMI watchdog timeout during PV Dom0 construction on some machines, which can be worked around by specifying "dma_bits" in Xen's cmdline manually. Fix the issue by ignoring MEMF_no_dma in cases when dma_bitsize is zero, which means there is no DMA zone. This shouldn't cause any issues for Dom0 because alloc_heap_pages() will first use higher memory addresses for satisfying memory allocation requests. Signed-off-by: Sergey Dyasli Reviewed-by: Jan Beulich --- diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 37a52aaa0d..f71d3bb7a1 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -2314,7 +2314,9 @@ struct page_info *alloc_domheap_pages( return NULL; } - if ( dma_bitsize && ((dma_zone = bits_to_zone(dma_bitsize)) < zone_hi) ) + if ( !dma_bitsize ) + memflags &= ~MEMF_no_dma; + else if ( (dma_zone = bits_to_zone(dma_bitsize)) < zone_hi ) pg = alloc_heap_pages(dma_zone + 1, zone_hi, order, memflags, d); if ( (pg == NULL) &&