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x86/numa_emulation: Introduce uniform split capability
The current NUMA emulation capabilities for splitting System RAM by a fixed size or by a set number of nodes may result in some nodes being larger than others. The implementation prioritizes establishing a minimum usable memory size over satisfying the requested number of NUMA nodes. Introduce a uniform split capability that evenly partitions each physical NUMA node into N emulated nodes. For example numa=fake=3U creates 6 emulated nodes total on a system that has 2 physical nodes. This capability is useful for debugging and evaluating platform memory-side-cache capabilities as described by the ACPI HMAT (see 5.2.27.5 Memory Side Cache Information Structure in ACPI 6.2a) Compare numa=fake=6 that results in only 5 nodes being created against numa=fake=3U which takes the 2 physical nodes and evenly divides them. numa=fake=6 available: 5 nodes (0-4) node 0 cpus: 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 node 0 size: 2648 MB node 0 free: 2443 MB node 1 cpus: 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 node 1 size: 2672 MB node 1 free: 2442 MB node 2 cpus: 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 node 2 size: 5291 MB node 2 free: 5278 MB node 3 cpus: 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 node 3 size: 2677 MB node 3 free: 2665 MB node 4 cpus: 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 node 4 size: 2676 MB node 4 free: 2663 MB node distances: node 0 1 2 3 4 0: 10 20 10 20 20 1: 20 10 20 10 10 2: 10 20 10 20 20 3: 20 10 20 10 10 4: 20 10 20 10 10 numa=fake=3U available: 6 nodes (0-5) node 0 cpus: 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 node 0 size: 2900 MB node 0 free: 2637 MB node 1 cpus: 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 node 1 size: 3023 MB node 1 free: 3012 MB node 2 cpus: 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 node 2 size: 2015 MB node 2 free: 2004 MB node 3 cpus: 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 node 3 size: 2704 MB node 3 free: 2522 MB node 4 cpus: 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 node 4 size: 2709 MB node 4 free: 2698 MB node 5 cpus: 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 node 5 size: 2612 MB node 5 free: 2601 MB node distances: node 0 1 2 3 4 5 0: 10 10 10 20 20 20 1: 10 10 10 20 20 20 2: 10 10 10 20 20 20 3: 20 20 20 10 10 10 4: 20 20 20 10 10 10 5: 20 20 20 10 10 10 Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/153089328617.27680.14930758266174305832.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dan Williams
Ingo Molnar
parent
3b6c62f363
commit
cc9aec03e5
2 changed files with 90 additions and 19 deletions
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@ -156,6 +156,10 @@ NUMA
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If given as an integer, fills all system RAM with N fake nodes
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interleaved over physical nodes.
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numa=fake=<N>U
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If given as an integer followed by 'U', it will divide each
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physical node into N emulated nodes.
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ACPI
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acpi=off Don't enable ACPI
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@ -198,40 +198,73 @@ static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
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return end;
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}
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static u64 uniform_size(u64 max_addr, u64 base, u64 hole, int nr_nodes)
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{
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unsigned long max_pfn = PHYS_PFN(max_addr);
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unsigned long base_pfn = PHYS_PFN(base);
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unsigned long hole_pfns = PHYS_PFN(hole);
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return PFN_PHYS((max_pfn - base_pfn - hole_pfns) / nr_nodes);
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}
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/*
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* Sets up fake nodes of `size' interleaved over physical nodes ranging from
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* `addr' to `max_addr'.
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*
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* Returns zero on success or negative on error.
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*/
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static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
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static int __init split_nodes_size_interleave_uniform(struct numa_meminfo *ei,
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struct numa_meminfo *pi,
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u64 addr, u64 max_addr, u64 size)
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u64 addr, u64 max_addr, u64 size,
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int nr_nodes, struct numa_memblk *pblk,
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int nid)
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{
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nodemask_t physnode_mask = numa_nodes_parsed;
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int i, ret, uniform = 0;
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u64 min_size;
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int nid = 0;
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int i, ret;
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if (!size)
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if ((!size && !nr_nodes) || (nr_nodes && !pblk))
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return -1;
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/*
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* The limit on emulated nodes is MAX_NUMNODES, so the size per node is
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* increased accordingly if the requested size is too small. This
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* creates a uniform distribution of node sizes across the entire
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* machine (but not necessarily over physical nodes).
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* In the 'uniform' case split the passed in physical node by
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* nr_nodes, in the non-uniform case, ignore the passed in
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* physical block and try to create nodes of at least size
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* @size.
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*
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* In the uniform case, split the nodes strictly by physical
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* capacity, i.e. ignore holes. In the non-uniform case account
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* for holes and treat @size as a minimum floor.
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*/
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min_size = (max_addr - addr - mem_hole_size(addr, max_addr)) / MAX_NUMNODES;
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min_size = max(min_size, FAKE_NODE_MIN_SIZE);
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if ((min_size & FAKE_NODE_MIN_HASH_MASK) < min_size)
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min_size = (min_size + FAKE_NODE_MIN_SIZE) &
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FAKE_NODE_MIN_HASH_MASK;
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if (!nr_nodes)
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nr_nodes = MAX_NUMNODES;
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else {
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nodes_clear(physnode_mask);
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node_set(pblk->nid, physnode_mask);
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uniform = 1;
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}
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if (uniform) {
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min_size = uniform_size(max_addr, addr, 0, nr_nodes);
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size = min_size;
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} else {
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/*
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* The limit on emulated nodes is MAX_NUMNODES, so the
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* size per node is increased accordingly if the
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* requested size is too small. This creates a uniform
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* distribution of node sizes across the entire machine
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* (but not necessarily over physical nodes).
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*/
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min_size = uniform_size(max_addr, addr,
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mem_hole_size(addr, max_addr), nr_nodes);
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}
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min_size = ALIGN(max(min_size, FAKE_NODE_MIN_SIZE), FAKE_NODE_MIN_SIZE);
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if (size < min_size) {
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pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
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size >> 20, min_size >> 20);
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size = min_size;
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}
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size &= FAKE_NODE_MIN_HASH_MASK;
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size = ALIGN_DOWN(size, FAKE_NODE_MIN_SIZE);
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/*
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* Fill physical nodes with fake nodes of size until there is no memory
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@ -248,10 +281,14 @@ static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
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node_clear(i, physnode_mask);
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continue;
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}
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start = pi->blk[phys_blk].start;
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limit = pi->blk[phys_blk].end;
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end = find_end_of_node(start, limit, size);
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if (uniform)
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end = start + size;
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else
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end = find_end_of_node(start, limit, size);
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/*
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* If there won't be at least FAKE_NODE_MIN_SIZE of
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* non-reserved memory in ZONE_DMA32 for the next node,
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@ -266,7 +303,8 @@ static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
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* next node, this one must extend to the end of the
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* physical node.
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*/
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if (limit - end - mem_hole_size(end, limit) < size)
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if ((limit - end - mem_hole_size(end, limit) < size)
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&& !uniform)
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end = limit;
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ret = emu_setup_memblk(ei, pi, nid++ % MAX_NUMNODES,
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@ -276,7 +314,15 @@ static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
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return ret;
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}
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}
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return 0;
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return nid;
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}
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static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
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struct numa_meminfo *pi,
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u64 addr, u64 max_addr, u64 size)
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{
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return split_nodes_size_interleave_uniform(ei, pi, addr, max_addr, size,
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0, NULL, NUMA_NO_NODE);
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}
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int __init setup_emu2phys_nid(int *dfl_phys_nid)
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@ -346,7 +392,28 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
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* the fixed node size. Otherwise, if it is just a single number N,
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* split the system RAM into N fake nodes.
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*/
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if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
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if (strchr(emu_cmdline, 'U')) {
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nodemask_t physnode_mask = numa_nodes_parsed;
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unsigned long n;
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int nid = 0;
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n = simple_strtoul(emu_cmdline, &emu_cmdline, 0);
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ret = -1;
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for_each_node_mask(i, physnode_mask) {
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ret = split_nodes_size_interleave_uniform(&ei, &pi,
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pi.blk[i].start, pi.blk[i].end, 0,
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n, &pi.blk[i], nid);
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if (ret < 0)
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break;
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if (ret < n) {
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pr_info("%s: phys: %d only got %d of %ld nodes, failing\n",
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__func__, i, ret, n);
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ret = -1;
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break;
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}
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nid = ret;
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}
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} else if (strchr(emu_cmdline, 'M') || strchr(emu_cmdline, 'G')) {
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u64 size;
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size = memparse(emu_cmdline, &emu_cmdline);
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