[patch 1/3] x86: fix numa emulation calculation of big nodes

[patch 1/3] x86: fix numa emulation calculation of big nodes

[David Rientjes]

numa=fake=N uses split_nodes_interleave() to partition the system into N
fake nodes.  Each node size must have be a multiple of
FAKE_NODE_MIN_SIZE, otherwise it is possible to get strange alignments.
Because of this, the remaining memory from each node when rounded to
FAKE_NODE_MIN_SIZE is consolidated into a number of "big nodes" that are
bigger than the rest.

The calculation of the number of big nodes is incorrect since it is using
a logical AND operator when it should be multiplying the rounded-off
portion of each node with N.

Signed-off-by: David Rientjes <rientjes@google.com>
---
 arch/x86/mm/numa_64.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -427,7 +427,7 @@ static int __init split_nodes_interleave(u64 addr, u64 max_addr,
 	 * Calculate the number of big nodes that can be allocated as a result
 	 * of consolidating the remainder.
 	 */
-	big = ((size & ~FAKE_NODE_MIN_HASH_MASK) & nr_nodes) /
+	big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
 		FAKE_NODE_MIN_SIZE;
 
 	size &= FAKE_NODE_MIN_HASH_MASK;

[patch 2/3] x86: add fixed node size option for numa emulation

[David Rientjes]

numa=fake=N specifies the number of fake nodes, N, to partition the
system into and then allocates them by interleaving over physical nodes.
This requires knowledge of the system capacity when attempting to
allocate nodes of a certain size: either very large nodes to benchmark
scalability of code that operates on individual nodes, or very small
nodes to find bugs in the VM.

This patch introduces numa=fake=<size>[MG] so it is possible to specify
the size of each node to allocate.  When used, nodes of the size
specified will be allocated and interleaved over the set of physical
nodes.

FAKE_NODE_MIN_SIZE was also moved to the more-appropriate
include/asm/numa_64.h.

Signed-off-by: David Rientjes <rientjes@google.com>
---
 Documentation/x86/x86_64/boot-options.txt |    4 +
 arch/x86/include/asm/mmzone_64.h          |    6 --
 arch/x86/include/asm/numa_64.h            |    5 +
 arch/x86/mm/numa_64.c                     |  117 +++++++++++++++++++++++++++--
 4 files changed, 118 insertions(+), 14 deletions(-)

diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -166,6 +166,10 @@ NUMA
 
   numa=noacpi   Don't parse the SRAT table for NUMA setup
 
+  numa=fake=<size>[MG]
+		If given as a memory unit, fills all system RAM with nodes of
+		size interleaved over physical nodes.
+
   numa=fake=CMDLINE
 		If a number, fakes CMDLINE nodes and ignores NUMA setup of the
 		actual machine.  Otherwise, system memory is configured
diff --git a/arch/x86/include/asm/mmzone_64.h b/arch/x86/include/asm/mmzone_64.h
--- a/arch/x86/include/asm/mmzone_64.h
+++ b/arch/x86/include/asm/mmzone_64.h
@@ -39,11 +39,5 @@ static inline __attribute__((pure)) int phys_to_nid(unsigned long addr)
 #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
 #define node_end_pfn(nid)       (NODE_DATA(nid)->node_start_pfn +	\
 				 NODE_DATA(nid)->node_spanned_pages)
-
-#ifdef CONFIG_NUMA_EMU
-#define FAKE_NODE_MIN_SIZE	(64 * 1024 * 1024)
-#define FAKE_NODE_MIN_HASH_MASK	(~(FAKE_NODE_MIN_SIZE - 1UL))
-#endif
-
 #endif
 #endif /* _ASM_X86_MMZONE_64_H */
diff --git a/arch/x86/include/asm/numa_64.h b/arch/x86/include/asm/numa_64.h
--- a/arch/x86/include/asm/numa_64.h
+++ b/arch/x86/include/asm/numa_64.h
@@ -36,6 +36,11 @@ extern void __cpuinit numa_set_node(int cpu, int node);
 extern void __cpuinit numa_clear_node(int cpu);
 extern void __cpuinit numa_add_cpu(int cpu);
 extern void __cpuinit numa_remove_cpu(int cpu);
+
+#ifdef CONFIG_NUMA_EMU
+#define FAKE_NODE_MIN_SIZE	((u64)64 << 20)
+#define FAKE_NODE_MIN_HASH_MASK	(~(FAKE_NODE_MIN_SIZE - 1UL))
+#endif /* CONFIG_NUMA_EMU */
 #else
 static inline void init_cpu_to_node(void)		{ }
 static inline void numa_set_node(int cpu, int node)	{ }
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -502,6 +502,102 @@ static int __init split_nodes_interleave(u64 addr, u64 max_addr,
 }
 
 /*
+ * Returns the end address of a node so that there is at least `size' amount of
+ * non-reserved memory or `max_addr' is reached.
+ */
+static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
+{
+	u64 end = start + size;
+
+	while (end - start - e820_hole_size(start, end) < size) {
+		end += FAKE_NODE_MIN_SIZE;
+		if (end > max_addr) {
+			end = max_addr;
+			break;
+		}
+	}
+	return end;
+}
+
+/*
+ * Sets up fake nodes of `size' interleaved over physical nodes ranging from
+ * `addr' to `max_addr'.  The return value is the number of nodes allocated.
+ */
+static int __init split_nodes_size_interleave(u64 addr, u64 max_addr, u64 size)
+{
+	nodemask_t physnode_mask = NODE_MASK_NONE;
+	u64 min_size;
+	int ret = 0;
+	int i;
+
+	if (!size)
+		return -1;
+	/*
+	 * The limit on emulated nodes is MAX_NUMNODES, so the size per node is
+	 * increased accordingly if the requested size is too small.  This
+	 * creates a uniform distribution of node sizes across the entire
+	 * machine (but not necessarily over physical nodes).
+	 */
+	min_size = (max_addr - addr - e820_hole_size(addr, max_addr)) /
+						MAX_NUMNODES;
+	min_size = max(min_size, FAKE_NODE_MIN_SIZE);
+	if ((min_size & FAKE_NODE_MIN_HASH_MASK) < min_size)
+		min_size = (min_size + FAKE_NODE_MIN_SIZE) &
+						FAKE_NODE_MIN_HASH_MASK;
+	if (size < min_size) {
+		pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
+			size >> 20, min_size >> 20);
+		size = min_size;
+	}
+	size &= FAKE_NODE_MIN_HASH_MASK;
+
+	for (i = 0; i < MAX_NUMNODES; i++)
+		if (physnodes[i].start != physnodes[i].end)
+			node_set(i, physnode_mask);
+	/*
+	 * Fill physical nodes with fake nodes of size until there is no memory
+	 * left on any of them.
+	 */
+	while (nodes_weight(physnode_mask)) {
+		for_each_node_mask(i, physnode_mask) {
+			u64 dma32_end = MAX_DMA32_PFN << PAGE_SHIFT;
+			u64 end;
+
+			end = find_end_of_node(physnodes[i].start,
+						physnodes[i].end, size);
+			/*
+			 * If there won't be at least FAKE_NODE_MIN_SIZE of
+			 * non-reserved memory in ZONE_DMA32 for the next node,
+			 * this one must extend to the boundary.
+			 */
+			if (end < dma32_end && dma32_end - end -
+			    e820_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
+				end = dma32_end;
+
+			/*
+			 * If there won't be enough non-reserved memory for the
+			 * next node, this one must extend to the end of the
+			 * physical node.
+			 */
+			if (physnodes[i].end - end -
+			    e820_hole_size(end, physnodes[i].end) < size)
+				end = physnodes[i].end;
+
+			/*
+			 * Setup the fake node that will be allocated as bootmem
+			 * later.  If setup_node_range() returns non-zero, there
+			 * is no more memory available on this physical node.
+			 */
+			if (setup_node_range(ret++, &physnodes[i].start,
+						end - physnodes[i].start,
+						physnodes[i].end) < 0)
+				node_clear(i, physnode_mask);
+		}
+	}
+	return ret;
+}
+
+/*
  * Splits num_nodes nodes up equally starting at node_start.  The return value
  * is the number of nodes split up and addr is adjusted to be at the end of the
  * last node allocated.
@@ -546,14 +642,7 @@ static int __init split_nodes_equally(u64 *addr, u64 max_addr, int node_start,
 		if (i == num_nodes + node_start - 1)
 			end = max_addr;
 		else
-			while (end - *addr - e820_hole_size(*addr, end) <
-			       size) {
-				end += FAKE_NODE_MIN_SIZE;
-				if (end > max_addr) {
-					end = max_addr;
-					break;
-				}
-			}
+			end = find_end_of_node(*addr, max_addr, size);
 		if (setup_node_range(i, addr, end - *addr, max_addr) < 0)
 			break;
 	}
@@ -589,6 +678,18 @@ static int __init numa_emulation(unsigned long start_pfn,
 
 	num_phys_nodes = setup_physnodes(addr, max_addr, acpi, k8);
 	/*
+	 * If the numa=fake command-line contains a 'M' or 'G', it represents
+	 * the fixed node size.
+	 */
+	if (strchr(cmdline, 'M') || strchr(cmdline, 'G')) {
+		size = memparse(cmdline, &cmdline);
+		num_nodes = split_nodes_size_interleave(addr, max_addr, size);
+		if (num_nodes < 0)
+			return num_nodes;
+		goto out;
+	}
+
+	/*
 	 * If the numa=fake command-line is just a single number N, split the
 	 * system RAM into N fake nodes.
 	 */

[tip:x86/numa] x86, numa: Add fixed node size option for numa emulation

[tip-bot for David Rientjes]

Commit-ID:  8df5bb34defd685fe86f60746bbf3d47d1c6f033
Gitweb:     http://git.kernel.org/tip/8df5bb34defd685fe86f60746bbf3d47d1c6f033
Author:     David Rientjes <rientjes@google.com>
AuthorDate: Mon, 15 Feb 2010 13:43:30 -0800
Committer:  H. Peter Anvin <hpa@zytor.com>
CommitDate: Mon, 15 Feb 2010 14:34:10 -0800

x86, numa: Add fixed node size option for numa emulation

numa=fake=N specifies the number of fake nodes, N, to partition the
system into and then allocates them by interleaving over physical nodes.
This requires knowledge of the system capacity when attempting to
allocate nodes of a certain size: either very large nodes to benchmark
scalability of code that operates on individual nodes, or very small
nodes to find bugs in the VM.

This patch introduces numa=fake=<size>[MG] so it is possible to specify
the size of each node to allocate.  When used, nodes of the size
specified will be allocated and interleaved over the set of physical
nodes.

FAKE_NODE_MIN_SIZE was also moved to the more-appropriate
include/asm/numa_64.h.

Signed-off-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1002151342510.26927@chino.kir.corp.google.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 Documentation/x86/x86_64/boot-options.txt |    4 +
 arch/x86/include/asm/mmzone_64.h          |    6 --
 arch/x86/include/asm/numa_64.h            |    5 +
 arch/x86/mm/numa_64.c                     |  117 +++++++++++++++++++++++++++--
 4 files changed, 118 insertions(+), 14 deletions(-)

diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
index 29a6ff8..01150c6 100644
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -166,6 +166,10 @@ NUMA
 
   numa=noacpi   Don't parse the SRAT table for NUMA setup
 
+  numa=fake=<size>[MG]
+		If given as a memory unit, fills all system RAM with nodes of
+		size interleaved over physical nodes.
+
   numa=fake=CMDLINE
 		If a number, fakes CMDLINE nodes and ignores NUMA setup of the
 		actual machine.  Otherwise, system memory is configured
diff --git a/arch/x86/include/asm/mmzone_64.h b/arch/x86/include/asm/mmzone_64.h
index a29f48c..288b96f 100644
--- a/arch/x86/include/asm/mmzone_64.h
+++ b/arch/x86/include/asm/mmzone_64.h
@@ -39,11 +39,5 @@ static inline __attribute__((pure)) int phys_to_nid(unsigned long addr)
 #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
 #define node_end_pfn(nid)       (NODE_DATA(nid)->node_start_pfn +	\
 				 NODE_DATA(nid)->node_spanned_pages)
-
-#ifdef CONFIG_NUMA_EMU
-#define FAKE_NODE_MIN_SIZE	(64 * 1024 * 1024)
-#define FAKE_NODE_MIN_HASH_MASK	(~(FAKE_NODE_MIN_SIZE - 1UL))
-#endif
-
 #endif
 #endif /* _ASM_X86_MMZONE_64_H */
diff --git a/arch/x86/include/asm/numa_64.h b/arch/x86/include/asm/numa_64.h
index c4ae822..823e070 100644
--- a/arch/x86/include/asm/numa_64.h
+++ b/arch/x86/include/asm/numa_64.h
@@ -36,6 +36,11 @@ extern void __cpuinit numa_set_node(int cpu, int node);
 extern void __cpuinit numa_clear_node(int cpu);
 extern void __cpuinit numa_add_cpu(int cpu);
 extern void __cpuinit numa_remove_cpu(int cpu);
+
+#ifdef CONFIG_NUMA_EMU
+#define FAKE_NODE_MIN_SIZE	((u64)64 << 20)
+#define FAKE_NODE_MIN_HASH_MASK	(~(FAKE_NODE_MIN_SIZE - 1UL))
+#endif /* CONFIG_NUMA_EMU */
 #else
 static inline void init_cpu_to_node(void)		{ }
 static inline void numa_set_node(int cpu, int node)	{ }
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index 2ecbe0c..c47c78b 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -502,6 +502,102 @@ static int __init split_nodes_interleave(u64 addr, u64 max_addr,
 }
 
 /*
+ * Returns the end address of a node so that there is at least `size' amount of
+ * non-reserved memory or `max_addr' is reached.
+ */
+static u64 __init find_end_of_node(u64 start, u64 max_addr, u64 size)
+{
+	u64 end = start + size;
+
+	while (end - start - e820_hole_size(start, end) < size) {
+		end += FAKE_NODE_MIN_SIZE;
+		if (end > max_addr) {
+			end = max_addr;
+			break;
+		}
+	}
+	return end;
+}
+
+/*
+ * Sets up fake nodes of `size' interleaved over physical nodes ranging from
+ * `addr' to `max_addr'.  The return value is the number of nodes allocated.
+ */
+static int __init split_nodes_size_interleave(u64 addr, u64 max_addr, u64 size)
+{
+	nodemask_t physnode_mask = NODE_MASK_NONE;
+	u64 min_size;
+	int ret = 0;
+	int i;
+
+	if (!size)
+		return -1;
+	/*
+	 * The limit on emulated nodes is MAX_NUMNODES, so the size per node is
+	 * increased accordingly if the requested size is too small.  This
+	 * creates a uniform distribution of node sizes across the entire
+	 * machine (but not necessarily over physical nodes).
+	 */
+	min_size = (max_addr - addr - e820_hole_size(addr, max_addr)) /
+						MAX_NUMNODES;
+	min_size = max(min_size, FAKE_NODE_MIN_SIZE);
+	if ((min_size & FAKE_NODE_MIN_HASH_MASK) < min_size)
+		min_size = (min_size + FAKE_NODE_MIN_SIZE) &
+						FAKE_NODE_MIN_HASH_MASK;
+	if (size < min_size) {
+		pr_err("Fake node size %LuMB too small, increasing to %LuMB\n",
+			size >> 20, min_size >> 20);
+		size = min_size;
+	}
+	size &= FAKE_NODE_MIN_HASH_MASK;
+
+	for (i = 0; i < MAX_NUMNODES; i++)
+		if (physnodes[i].start != physnodes[i].end)
+			node_set(i, physnode_mask);
+	/*
+	 * Fill physical nodes with fake nodes of size until there is no memory
+	 * left on any of them.
+	 */
+	while (nodes_weight(physnode_mask)) {
+		for_each_node_mask(i, physnode_mask) {
+			u64 dma32_end = MAX_DMA32_PFN << PAGE_SHIFT;
+			u64 end;
+
+			end = find_end_of_node(physnodes[i].start,
+						physnodes[i].end, size);
+			/*
+			 * If there won't be at least FAKE_NODE_MIN_SIZE of
+			 * non-reserved memory in ZONE_DMA32 for the next node,
+			 * this one must extend to the boundary.
+			 */
+			if (end < dma32_end && dma32_end - end -
+			    e820_hole_size(end, dma32_end) < FAKE_NODE_MIN_SIZE)
+				end = dma32_end;
+
+			/*
+			 * If there won't be enough non-reserved memory for the
+			 * next node, this one must extend to the end of the
+			 * physical node.
+			 */
+			if (physnodes[i].end - end -
+			    e820_hole_size(end, physnodes[i].end) < size)
+				end = physnodes[i].end;
+
+			/*
+			 * Setup the fake node that will be allocated as bootmem
+			 * later.  If setup_node_range() returns non-zero, there
+			 * is no more memory available on this physical node.
+			 */
+			if (setup_node_range(ret++, &physnodes[i].start,
+						end - physnodes[i].start,
+						physnodes[i].end) < 0)
+				node_clear(i, physnode_mask);
+		}
+	}
+	return ret;
+}
+
+/*
  * Splits num_nodes nodes up equally starting at node_start.  The return value
  * is the number of nodes split up and addr is adjusted to be at the end of the
  * last node allocated.
@@ -546,14 +642,7 @@ static int __init split_nodes_equally(u64 *addr, u64 max_addr, int node_start,
 		if (i == num_nodes + node_start - 1)
 			end = max_addr;
 		else
-			while (end - *addr - e820_hole_size(*addr, end) <
-			       size) {
-				end += FAKE_NODE_MIN_SIZE;
-				if (end > max_addr) {
-					end = max_addr;
-					break;
-				}
-			}
+			end = find_end_of_node(*addr, max_addr, size);
 		if (setup_node_range(i, addr, end - *addr, max_addr) < 0)
 			break;
 	}
@@ -589,6 +678,18 @@ static int __init numa_emulation(unsigned long start_pfn,
 
 	num_phys_nodes = setup_physnodes(addr, max_addr, acpi, k8);
 	/*
+	 * If the numa=fake command-line contains a 'M' or 'G', it represents
+	 * the fixed node size.
+	 */
+	if (strchr(cmdline, 'M') || strchr(cmdline, 'G')) {
+		size = memparse(cmdline, &cmdline);
+		num_nodes = split_nodes_size_interleave(addr, max_addr, size);
+		if (num_nodes < 0)
+			return num_nodes;
+		goto out;
+	}
+
+	/*
 	 * If the numa=fake command-line is just a single number N, split the
 	 * system RAM into N fake nodes.
 	 */

[patch 3/3] x86: remove configurable node size support for numa emulation

[David Rientjes]

Now that numa=fake=<size>[MG] is implemented, it is possible to remove 
configurable node size support.  The command-line parsing was already
broken (numa=fake=*128, for example, would not work) and since fake nodes
are now interleaved over physical nodes, this support is no longer
required.

Signed-off-by: David Rientjes <rientjes@google.com>
---
 Documentation/x86/x86_64/boot-options.txt |   16 +---
 arch/x86/mm/numa_64.c                     |  160 +++--------------------------
 2 files changed, 16 insertions(+), 160 deletions(-)

diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -170,19 +170,9 @@ NUMA
 		If given as a memory unit, fills all system RAM with nodes of
 		size interleaved over physical nodes.
 
-  numa=fake=CMDLINE
-		If a number, fakes CMDLINE nodes and ignores NUMA setup of the
-		actual machine.  Otherwise, system memory is configured
-		depending on the sizes and coefficients listed.  For example:
-			numa=fake=2*512,1024,4*256,*128
-		gives two 512M nodes, a 1024M node, four 256M nodes, and the
-		rest split into 128M chunks.  If the last character of CMDLINE
-		is a *, the remaining memory is divided up equally among its
-		coefficient:
-			numa=fake=2*512,2*
-		gives two 512M nodes and the rest split into two nodes.
-		Otherwise, the remaining system RAM is allocated to an
-		additional node.
+  numa=fake=<N>
+		If given as an integer, fills all system RAM with N fake nodes
+		interleaved over physical nodes.
 
 ACPI
 
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -598,172 +598,38 @@ static int __init split_nodes_size_interleave(u64 addr, u64 max_addr, u64 size)
 }
 
 /*
- * Splits num_nodes nodes up equally starting at node_start.  The return value
- * is the number of nodes split up and addr is adjusted to be at the end of the
- * last node allocated.
- */
-static int __init split_nodes_equally(u64 *addr, u64 max_addr, int node_start,
-				      int num_nodes)
-{
-	unsigned int big;
-	u64 size;
-	int i;
-
-	if (num_nodes <= 0)
-		return -1;
-	if (num_nodes > MAX_NUMNODES)
-		num_nodes = MAX_NUMNODES;
-	size = (max_addr - *addr - e820_hole_size(*addr, max_addr)) /
-	       num_nodes;
-	/*
-	 * Calculate the number of big nodes that can be allocated as a result
-	 * of consolidating the leftovers.
-	 */
-	big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * num_nodes) /
-	      FAKE_NODE_MIN_SIZE;
-
-	/* Round down to nearest FAKE_NODE_MIN_SIZE. */
-	size &= FAKE_NODE_MIN_HASH_MASK;
-	if (!size) {
-		printk(KERN_ERR "Not enough memory for each node.  "
-		       "NUMA emulation disabled.\n");
-		return -1;
-	}
-
-	for (i = node_start; i < num_nodes + node_start; i++) {
-		u64 end = *addr + size;
-
-		if (i < big)
-			end += FAKE_NODE_MIN_SIZE;
-		/*
-		 * The final node can have the remaining system RAM.  Other
-		 * nodes receive roughly the same amount of available pages.
-		 */
-		if (i == num_nodes + node_start - 1)
-			end = max_addr;
-		else
-			end = find_end_of_node(*addr, max_addr, size);
-		if (setup_node_range(i, addr, end - *addr, max_addr) < 0)
-			break;
-	}
-	return i - node_start + 1;
-}
-
-/*
- * Splits the remaining system RAM into chunks of size.  The remaining memory is
- * always assigned to a final node and can be asymmetric.  Returns the number of
- * nodes split.
- */
-static int __init split_nodes_by_size(u64 *addr, u64 max_addr, int node_start,
-				      u64 size)
-{
-	int i = node_start;
-	size = (size << 20) & FAKE_NODE_MIN_HASH_MASK;
-	while (!setup_node_range(i++, addr, size, max_addr))
-		;
-	return i - node_start;
-}
-
-/*
  * Sets up the system RAM area from start_pfn to last_pfn according to the
  * numa=fake command-line option.
  */
 static int __init numa_emulation(unsigned long start_pfn,
 			unsigned long last_pfn, int acpi, int k8)
 {
-	u64 size, addr = start_pfn << PAGE_SHIFT;
+	u64 addr = start_pfn << PAGE_SHIFT;
 	u64 max_addr = last_pfn << PAGE_SHIFT;
-	int num_nodes = 0, num = 0, coeff_flag, coeff = -1, i;
 	int num_phys_nodes;
+	int num_nodes;
+	int i;
 
 	num_phys_nodes = setup_physnodes(addr, max_addr, acpi, k8);
 	/*
 	 * If the numa=fake command-line contains a 'M' or 'G', it represents
-	 * the fixed node size.
+	 * the fixed node size.  Otherwise, if it is just a single number N,
+	 * split the system RAM into N fake nodes.
 	 */
 	if (strchr(cmdline, 'M') || strchr(cmdline, 'G')) {
+		u64 size;
+
 		size = memparse(cmdline, &cmdline);
 		num_nodes = split_nodes_size_interleave(addr, max_addr, size);
-		if (num_nodes < 0)
-			return num_nodes;
-		goto out;
-	}
+	} else {
+		unsigned long n;
 
-	/*
-	 * If the numa=fake command-line is just a single number N, split the
-	 * system RAM into N fake nodes.
-	 */
-	if (!strchr(cmdline, '*') && !strchr(cmdline, ',')) {
-		long n = simple_strtol(cmdline, NULL, 0);
-
-		num_nodes = split_nodes_interleave(addr, max_addr,
-							num_phys_nodes, n);
-		if (num_nodes < 0)
-			return num_nodes;
-		goto out;
+		n = simple_strtoul(cmdline, NULL, 0);
+		num_nodes = split_nodes_interleave(addr, max_addr, num_phys_nodes, n);
 	}
 
-	/* Parse the command line. */
-	for (coeff_flag = 0; ; cmdline++) {
-		if (*cmdline && isdigit(*cmdline)) {
-			num = num * 10 + *cmdline - '0';
-			continue;
-		}
-		if (*cmdline == '*') {
-			if (num > 0)
-				coeff = num;
-			coeff_flag = 1;
-		}
-		if (!*cmdline || *cmdline == ',') {
-			if (!coeff_flag)
-				coeff = 1;
-			/*
-			 * Round down to the nearest FAKE_NODE_MIN_SIZE.
-			 * Command-line coefficients are in megabytes.
-			 */
-			size = ((u64)num << 20) & FAKE_NODE_MIN_HASH_MASK;
-			if (size)
-				for (i = 0; i < coeff; i++, num_nodes++)
-					if (setup_node_range(num_nodes, &addr,
-						size, max_addr) < 0)
-						goto done;
-			if (!*cmdline)
-				break;
-			coeff_flag = 0;
-			coeff = -1;
-		}
-		num = 0;
-	}
-done:
-	if (!num_nodes)
-		return -1;
-	/* Fill remainder of system RAM, if appropriate. */
-	if (addr < max_addr) {
-		if (coeff_flag && coeff < 0) {
-			/* Split remaining nodes into num-sized chunks */
-			num_nodes += split_nodes_by_size(&addr, max_addr,
-							 num_nodes, num);
-			goto out;
-		}
-		switch (*(cmdline - 1)) {
-		case '*':
-			/* Split remaining nodes into coeff chunks */
-			if (coeff <= 0)
-				break;
-			num_nodes += split_nodes_equally(&addr, max_addr,
-							 num_nodes, coeff);
-			break;
-		case ',':
-			/* Do not allocate remaining system RAM */
-			break;
-		default:
-			/* Give one final node */
-			setup_node_range(num_nodes, &addr, max_addr - addr,
-					 max_addr);
-			num_nodes++;
-		}
-	}
-out:
+	if (num_nodes < 0)
+		return num_nodes;
 	memnode_shift = compute_hash_shift(nodes, num_nodes, NULL);
 	if (memnode_shift < 0) {
 		memnode_shift = 0;

[tip:x86/numa] x86, numa: Remove configurable node size support for numa emulation

[tip-bot for David Rientjes]

Commit-ID:  ca2107c9d6cf44fb915402d6f12b9d9ff3925cd7
Gitweb:     http://git.kernel.org/tip/ca2107c9d6cf44fb915402d6f12b9d9ff3925cd7
Author:     David Rientjes <rientjes@google.com>
AuthorDate: Mon, 15 Feb 2010 13:43:33 -0800
Committer:  H. Peter Anvin <hpa@zytor.com>
CommitDate: Mon, 15 Feb 2010 14:34:18 -0800

x86, numa: Remove configurable node size support for numa emulation

Now that numa=fake=<size>[MG] is implemented, it is possible to remove
configurable node size support.  The command-line parsing was already
broken (numa=fake=*128, for example, would not work) and since fake nodes
are now interleaved over physical nodes, this support is no longer
required.

Signed-off-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1002151343080.26927@chino.kir.corp.google.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 Documentation/x86/x86_64/boot-options.txt |   16 +---
 arch/x86/mm/numa_64.c                     |  160 +++--------------------------
 2 files changed, 16 insertions(+), 160 deletions(-)

diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt
index 01150c6..7fbbaf8 100644
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -170,19 +170,9 @@ NUMA
 		If given as a memory unit, fills all system RAM with nodes of
 		size interleaved over physical nodes.
 
-  numa=fake=CMDLINE
-		If a number, fakes CMDLINE nodes and ignores NUMA setup of the
-		actual machine.  Otherwise, system memory is configured
-		depending on the sizes and coefficients listed.  For example:
-			numa=fake=2*512,1024,4*256,*128
-		gives two 512M nodes, a 1024M node, four 256M nodes, and the
-		rest split into 128M chunks.  If the last character of CMDLINE
-		is a *, the remaining memory is divided up equally among its
-		coefficient:
-			numa=fake=2*512,2*
-		gives two 512M nodes and the rest split into two nodes.
-		Otherwise, the remaining system RAM is allocated to an
-		additional node.
+  numa=fake=<N>
+		If given as an integer, fills all system RAM with N fake nodes
+		interleaved over physical nodes.
 
 ACPI
 
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index c47c78b..3307ea8 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -598,172 +598,38 @@ static int __init split_nodes_size_interleave(u64 addr, u64 max_addr, u64 size)
 }
 
 /*
- * Splits num_nodes nodes up equally starting at node_start.  The return value
- * is the number of nodes split up and addr is adjusted to be at the end of the
- * last node allocated.
- */
-static int __init split_nodes_equally(u64 *addr, u64 max_addr, int node_start,
-				      int num_nodes)
-{
-	unsigned int big;
-	u64 size;
-	int i;
-
-	if (num_nodes <= 0)
-		return -1;
-	if (num_nodes > MAX_NUMNODES)
-		num_nodes = MAX_NUMNODES;
-	size = (max_addr - *addr - e820_hole_size(*addr, max_addr)) /
-	       num_nodes;
-	/*
-	 * Calculate the number of big nodes that can be allocated as a result
-	 * of consolidating the leftovers.
-	 */
-	big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * num_nodes) /
-	      FAKE_NODE_MIN_SIZE;
-
-	/* Round down to nearest FAKE_NODE_MIN_SIZE. */
-	size &= FAKE_NODE_MIN_HASH_MASK;
-	if (!size) {
-		printk(KERN_ERR "Not enough memory for each node.  "
-		       "NUMA emulation disabled.\n");
-		return -1;
-	}
-
-	for (i = node_start; i < num_nodes + node_start; i++) {
-		u64 end = *addr + size;
-
-		if (i < big)
-			end += FAKE_NODE_MIN_SIZE;
-		/*
-		 * The final node can have the remaining system RAM.  Other
-		 * nodes receive roughly the same amount of available pages.
-		 */
-		if (i == num_nodes + node_start - 1)
-			end = max_addr;
-		else
-			end = find_end_of_node(*addr, max_addr, size);
-		if (setup_node_range(i, addr, end - *addr, max_addr) < 0)
-			break;
-	}
-	return i - node_start + 1;
-}
-
-/*
- * Splits the remaining system RAM into chunks of size.  The remaining memory is
- * always assigned to a final node and can be asymmetric.  Returns the number of
- * nodes split.
- */
-static int __init split_nodes_by_size(u64 *addr, u64 max_addr, int node_start,
-				      u64 size)
-{
-	int i = node_start;
-	size = (size << 20) & FAKE_NODE_MIN_HASH_MASK;
-	while (!setup_node_range(i++, addr, size, max_addr))
-		;
-	return i - node_start;
-}
-
-/*
  * Sets up the system RAM area from start_pfn to last_pfn according to the
  * numa=fake command-line option.
  */
 static int __init numa_emulation(unsigned long start_pfn,
 			unsigned long last_pfn, int acpi, int k8)
 {
-	u64 size, addr = start_pfn << PAGE_SHIFT;
+	u64 addr = start_pfn << PAGE_SHIFT;
 	u64 max_addr = last_pfn << PAGE_SHIFT;
-	int num_nodes = 0, num = 0, coeff_flag, coeff = -1, i;
 	int num_phys_nodes;
+	int num_nodes;
+	int i;
 
 	num_phys_nodes = setup_physnodes(addr, max_addr, acpi, k8);
 	/*
 	 * If the numa=fake command-line contains a 'M' or 'G', it represents
-	 * the fixed node size.
+	 * the fixed node size.  Otherwise, if it is just a single number N,
+	 * split the system RAM into N fake nodes.
 	 */
 	if (strchr(cmdline, 'M') || strchr(cmdline, 'G')) {
+		u64 size;
+
 		size = memparse(cmdline, &cmdline);
 		num_nodes = split_nodes_size_interleave(addr, max_addr, size);
-		if (num_nodes < 0)
-			return num_nodes;
-		goto out;
-	}
+	} else {
+		unsigned long n;
 
-	/*
-	 * If the numa=fake command-line is just a single number N, split the
-	 * system RAM into N fake nodes.
-	 */
-	if (!strchr(cmdline, '*') && !strchr(cmdline, ',')) {
-		long n = simple_strtol(cmdline, NULL, 0);
-
-		num_nodes = split_nodes_interleave(addr, max_addr,
-							num_phys_nodes, n);
-		if (num_nodes < 0)
-			return num_nodes;
-		goto out;
+		n = simple_strtoul(cmdline, NULL, 0);
+		num_nodes = split_nodes_interleave(addr, max_addr, num_phys_nodes, n);
 	}
 
-	/* Parse the command line. */
-	for (coeff_flag = 0; ; cmdline++) {
-		if (*cmdline && isdigit(*cmdline)) {
-			num = num * 10 + *cmdline - '0';
-			continue;
-		}
-		if (*cmdline == '*') {
-			if (num > 0)
-				coeff = num;
-			coeff_flag = 1;
-		}
-		if (!*cmdline || *cmdline == ',') {
-			if (!coeff_flag)
-				coeff = 1;
-			/*
-			 * Round down to the nearest FAKE_NODE_MIN_SIZE.
-			 * Command-line coefficients are in megabytes.
-			 */
-			size = ((u64)num << 20) & FAKE_NODE_MIN_HASH_MASK;
-			if (size)
-				for (i = 0; i < coeff; i++, num_nodes++)
-					if (setup_node_range(num_nodes, &addr,
-						size, max_addr) < 0)
-						goto done;
-			if (!*cmdline)
-				break;
-			coeff_flag = 0;
-			coeff = -1;
-		}
-		num = 0;
-	}
-done:
-	if (!num_nodes)
-		return -1;
-	/* Fill remainder of system RAM, if appropriate. */
-	if (addr < max_addr) {
-		if (coeff_flag && coeff < 0) {
-			/* Split remaining nodes into num-sized chunks */
-			num_nodes += split_nodes_by_size(&addr, max_addr,
-							 num_nodes, num);
-			goto out;
-		}
-		switch (*(cmdline - 1)) {
-		case '*':
-			/* Split remaining nodes into coeff chunks */
-			if (coeff <= 0)
-				break;
-			num_nodes += split_nodes_equally(&addr, max_addr,
-							 num_nodes, coeff);
-			break;
-		case ',':
-			/* Do not allocate remaining system RAM */
-			break;
-		default:
-			/* Give one final node */
-			setup_node_range(num_nodes, &addr, max_addr - addr,
-					 max_addr);
-			num_nodes++;
-		}
-	}
-out:
+	if (num_nodes < 0)
+		return num_nodes;
 	memnode_shift = compute_hash_shift(nodes, num_nodes, NULL);
 	if (memnode_shift < 0) {
 		memnode_shift = 0;

[tip:x86/numa] x86, numa: Fix numa emulation calculation of big nodes

[tip-bot for David Rientjes]

Commit-ID:  68fd111e02b979876359c7b471a8bcbca0628b75
Gitweb:     http://git.kernel.org/tip/68fd111e02b979876359c7b471a8bcbca0628b75
Author:     David Rientjes <rientjes@google.com>
AuthorDate: Mon, 15 Feb 2010 13:43:25 -0800
Committer:  H. Peter Anvin <hpa@zytor.com>
CommitDate: Mon, 15 Feb 2010 14:34:04 -0800

x86, numa: Fix numa emulation calculation of big nodes

numa=fake=N uses split_nodes_interleave() to partition the system into N
fake nodes.  Each node size must have be a multiple of
FAKE_NODE_MIN_SIZE, otherwise it is possible to get strange alignments.
Because of this, the remaining memory from each node when rounded to
FAKE_NODE_MIN_SIZE is consolidated into a number of "big nodes" that are
bigger than the rest.

The calculation of the number of big nodes is incorrect since it is using
a logical AND operator when it should be multiplying the rounded-off
portion of each node with N.

Signed-off-by: David Rientjes <rientjes@google.com>
LKML-Reference: <alpine.DEB.2.00.1002151342230.26927@chino.kir.corp.google.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/mm/numa_64.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index 83bbc70..2ecbe0c 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -427,7 +427,7 @@ static int __init split_nodes_interleave(u64 addr, u64 max_addr,
 	 * Calculate the number of big nodes that can be allocated as a result
 	 * of consolidating the remainder.
 	 */
-	big = ((size & ~FAKE_NODE_MIN_HASH_MASK) & nr_nodes) /
+	big = ((size & ~FAKE_NODE_MIN_HASH_MASK) * nr_nodes) /
 		FAKE_NODE_MIN_SIZE;
 
 	size &= FAKE_NODE_MIN_HASH_MASK;