[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen staging-4.9] mm/page_alloc: fix MEMF_no_dma allocations for single NUMA
commit b366d29102a78a67e62d4a31472a99a9fb2323d7 Author: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx> AuthorDate: Fri Feb 1 12:06:21 2019 +0100 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Fri Feb 1 12:06:21 2019 +0100 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 <sergey.dyasli@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> master commit: 5ac2dddb173b69be259ce4b259e73f971a4816c1 master date: 2019-01-09 15:45:14 +0100 --- xen/common/page_alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 7d8c37ef36..adede05509 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -1796,7 +1796,9 @@ struct page_info *alloc_domheap_pages( if ( memflags & MEMF_no_owner ) memflags |= MEMF_no_refcount; - 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) && -- generated by git-patchbot for /home/xen/git/xen.git#staging-4.9 _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/xen-changelog
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