From 085f8e88ba73b7ff80298b0085f6e615d3b5c45f Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Fri, 31 Oct 2014 16:38:42 +0000 Subject: [PATCH] pc: count in 1Gb hugepage alignment when sizing hotplug-memory container if DIMMs with different size/alignment are interleaved in creation order, it could lead to hotplug-memory container fragmentation and following inability to use all RAM upto maxmem. For example: -m 4G,slots=3,maxmem=7G -object memory-backend-file,id=mem-1,size=256M,mem-path=/pagesize-2MB -device pc-dimm,id=mem1,memdev=mem-1 -object memory-backend-file,id=mem-2,size=1G,mem-path=/pagesize-1GB -device pc-dimm,id=mem2,memdev=mem-2 -object memory-backend-file,id=mem-3,size=256M,mem-path=/pagesize-2MB -device pc-dimm,id=mem3,memdev=mem-3 fragments hotplug-memory container and doesn't allow to use 1GB hugepage backend to consume remainig 1Gb. To ease managment factor count in max 1Gb alignment for each memory slot when sizing hotplug-memory region so that regadless of fragmentaion it would be possible to add max aligned DIMM. Signed-off-by: Igor Mammedov Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/pc.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index 3d732cf5a5..8be50a4ad6 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -1247,6 +1247,11 @@ FWCfgState *pc_memory_init(MachineState *machine, pcms->hotplug_memory_base = ROUND_UP(0x100000000ULL + above_4g_mem_size, 1ULL << 30); + if (pcms->enforce_aligned_dimm) { + /* size hotplug region assuming 1G page max alignment per slot */ + hotplug_mem_size += (1ULL << 30) * machine->ram_slots; + } + if ((pcms->hotplug_memory_base + hotplug_mem_size) < hotplug_mem_size) { error_report("unsupported amount of maximum memory: " RAM_ADDR_FMT,