Re: [PATCH -mm] x86 allnoconfig memory model

From: Christoph Lameter
Date: Mon Nov 26 2007 - 18:20:47 EST

On Mon, 26 Nov 2007, Andrew Morton wrote:

> b) I go direct to master.kernel.org. Probably that's only worth five
> minutes nowadays - it used to be worth hours, but kernel.org got better.

Updated patch (including Randy's fix) against git-x86 mm.



x86_64: Make sparsemem/vmemmap the only memory model V3

V2->V3:
- Rediff against mm git-x86

V1->V2:
- Rediff against new upstream x86 code that unifies the Kconfig files.

Use sparsemem as the only memory model for UP, SMP and NUMA.
Measurements indicate that DISCONTIGMEM has a higher overhead
than sparsemem. And FLATMEMs benefits are minimal. So I think its
best to simply standardize on sparsemem.

Results of page allocator tests (test can be had via git from slab git
tree branch tests)

Measurements in cycle counts. 1000 allocations were performed and then the
average cycle count was calculated.

Order FlatMem Discontig SparseMem
0 639 665 641
1 567 647 593
2 679 774 692
3 763 967 781
4 961 1501 962
5 1356 2344 1392
6 2224 3982 2336
7 4869 7225 5074
8 12500 14048 12732
9 27926 28223 28165
10 58578 58714 58682

(Note that FlatMem is an SMP config and the rest NUMA configurations)

Memory use:

SMP Sparsemem
-------------

Kernel size:

text data bss dec hex filename
3849268 397739 1264856 5511863 541ab7 vmlinux

total used free shared buffers cached
Mem: 8242252 41164 8201088 0 352 11512
-/+ buffers/cache: 29300 8212952
Swap: 9775512 0 9775512

SMP Flatmem
-----------

Kernel size:

text data bss dec hex filename
3844612 397739 1264536 5506887 540747 vmlinux

So 4.5k growth in text size vs. FLATMEM.

total used free shared buffers cached
Mem: 8244052 40544 8203508 0 352 11484
-/+ buffers/cache: 28708 8215344

2k growth in overall memory use after boot.



NUMA discontig:

text data bss dec hex filename
3888124 470659 1276504 5635287 55fcd7 vmlinux

total used free shared buffers cached
Mem: 8256256 56908 8199348 0 352 11496
-/+ buffers/cache: 45060 8211196
Swap: 9775512 0 9775512

NUMA sparse:

text data bss dec hex filename
3896428 470659 1276824 5643911 561e87 vmlinux


8k text growth. Given that we fully inline virt_to_page and friends now
that is rather good.

total used free shared buffers cached
Mem: 8264720 57240 8207480 0 352 11516
-/+ buffers/cache: 45372 8219348
Swap: 9775512 0 9775512

The total available memory is increased by 8k.


This patch makes sparsemem the default and removes discontig and
flatmem support from x86.

Acked-by: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>

---
arch/x86/Kconfig | 22 +++++---------
arch/x86/configs/x86_64_defconfig | 9 -----
arch/x86/kernel/machine_kexec_64.c | 5 ---
arch/x86/mm/init_64.c | 30 -------------------
arch/x86/mm/ioremap_64.c | 17 -----------
arch/x86/mm/numa_64.c | 21 -------------
arch/x86/mm/srat_64.c | 57 -------------------------------------
include/asm-x86/mmzone_64.h | 6 ---
include/asm-x86/page_64.h | 3 -
9 files changed, 9 insertions(+), 161 deletions(-)

Index: linux-2.6-x86/arch/x86/configs/x86_64_defconfig
===================================================================
--- linux-2.6-x86.orig/arch/x86/configs/x86_64_defconfig 2007-11-26 13:53:18.927361771 -0800
+++ linux-2.6-x86/arch/x86/configs/x86_64_defconfig 2007-11-26 15:15:41.430361615 -0800
@@ -145,15 +145,6 @@ CONFIG_K8_NUMA=y
CONFIG_NODES_SHIFT=6
CONFIG_X86_64_ACPI_NUMA=y
CONFIG_NUMA_EMU=y
-CONFIG_ARCH_DISCONTIGMEM_ENABLE=y
-CONFIG_ARCH_DISCONTIGMEM_DEFAULT=y
-CONFIG_ARCH_SPARSEMEM_ENABLE=y
-CONFIG_SELECT_MEMORY_MODEL=y
-# CONFIG_FLATMEM_MANUAL is not set
-CONFIG_DISCONTIGMEM_MANUAL=y
-# CONFIG_SPARSEMEM_MANUAL is not set
-CONFIG_DISCONTIGMEM=y
-CONFIG_FLAT_NODE_MEM_MAP=y
CONFIG_NEED_MULTIPLE_NODES=y
# CONFIG_SPARSEMEM_STATIC is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
Index: linux-2.6-x86/arch/x86/kernel/machine_kexec_64.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/kernel/machine_kexec_64.c 2007-11-26 13:53:18.939362118 -0800
+++ linux-2.6-x86/arch/x86/kernel/machine_kexec_64.c 2007-11-26 15:15:41.430361615 -0800
@@ -234,10 +234,5 @@ NORET_TYPE void machine_kexec(struct kim
void arch_crash_save_vmcoreinfo(void)
{
VMCOREINFO_SYMBOL(init_level4_pgt);
-
-#ifdef CONFIG_ARCH_DISCONTIGMEM_ENABLE
- VMCOREINFO_SYMBOL(node_data);
- VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
-#endif
}

Index: linux-2.6-x86/arch/x86/mm/ioremap_64.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/mm/ioremap_64.c 2007-11-26 13:53:18.951362033 -0800
+++ linux-2.6-x86/arch/x86/mm/ioremap_64.c 2007-11-26 15:15:41.430361615 -0800
@@ -86,23 +86,6 @@ void __iomem * __ioremap(unsigned long p
if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
return (__force void __iomem *)phys_to_virt(phys_addr);

-#ifdef CONFIG_FLATMEM
- /*
- * Don't allow anybody to remap normal RAM that we're using..
- */
- if (last_addr < virt_to_phys(high_memory)) {
- char *t_addr, *t_end;
- struct page *page;
-
- t_addr = __va(phys_addr);
- t_end = t_addr + (size - 1);
-
- for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
- if(!PageReserved(page))
- return NULL;
- }
-#endif
-
pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_GLOBAL
| _PAGE_DIRTY | _PAGE_ACCESSED | flags);
/*
Index: linux-2.6-x86/arch/x86/mm/numa_64.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/mm/numa_64.c 2007-11-26 15:15:26.130611458 -0800
+++ linux-2.6-x86/arch/x86/mm/numa_64.c 2007-11-26 15:15:41.430361615 -0800
@@ -153,12 +153,10 @@ int __init compute_hash_shift(struct boo
return shift;
}

-#ifdef CONFIG_SPARSEMEM
int early_pfn_to_nid(unsigned long pfn)
{
return phys_to_nid(pfn << PAGE_SHIFT);
}
-#endif

static void * __init early_node_mem(int nodeid, unsigned long start,
unsigned long end, unsigned long size)
@@ -635,23 +633,4 @@ void __init init_cpu_to_node(void)
}
}

-#ifdef CONFIG_DISCONTIGMEM
-/*
- * Functions to convert PFNs from/to per node page addresses.
- * These are out of line because they are quite big.
- * They could be all tuned by pre caching more state.
- * Should do that.
- */

-int pfn_valid(unsigned long pfn)
-{
- unsigned nid;
- if (pfn >= num_physpages)
- return 0;
- nid = pfn_to_nid(pfn);
- if (nid == 0xff)
- return 0;
- return pfn >= node_start_pfn(nid) && (pfn) < node_end_pfn(nid);
-}
-EXPORT_SYMBOL(pfn_valid);
-#endif
Index: linux-2.6-x86/include/asm-x86/mmzone_64.h
===================================================================
--- linux-2.6-x86.orig/include/asm-x86/mmzone_64.h 2007-11-26 15:15:26.471361483 -0800
+++ linux-2.6-x86/include/asm-x86/mmzone_64.h 2007-11-26 15:15:41.430361615 -0800
@@ -43,12 +43,6 @@ static inline __attribute__((pure)) int

extern int early_pfn_to_nid(unsigned long pfn);

-#ifdef CONFIG_DISCONTIGMEM
-#define pfn_to_nid(pfn) phys_to_nid((unsigned long)(pfn) << PAGE_SHIFT)
-
-extern int pfn_valid(unsigned long pfn);
-#endif
-
#ifdef CONFIG_NUMA_EMU
#define FAKE_NODE_MIN_SIZE (64*1024*1024)
#define FAKE_NODE_MIN_HASH_MASK (~(FAKE_NODE_MIN_SIZE - 1uL))
Index: linux-2.6-x86/include/asm-x86/page_64.h
===================================================================
--- linux-2.6-x86.orig/include/asm-x86/page_64.h 2007-11-26 15:15:26.475361591 -0800
+++ linux-2.6-x86/include/asm-x86/page_64.h 2007-11-26 15:15:41.430361615 -0800
@@ -127,9 +127,6 @@ extern unsigned long __phys_addr(unsigne
#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
#define __boot_va(x) __va(x)
#define __boot_pa(x) __pa(x)
-#ifdef CONFIG_FLATMEM
-#define pfn_valid(pfn) ((pfn) < end_pfn)
-#endif

#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
Index: linux-2.6-x86/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/mm/init_64.c 2007-11-26 15:15:26.122611468 -0800
+++ linux-2.6-x86/arch/x86/mm/init_64.c 2007-11-26 15:15:41.430361615 -0800
@@ -486,34 +486,6 @@ EXPORT_SYMBOL_GPL(memory_add_physaddr_to

#endif /* CONFIG_MEMORY_HOTPLUG */

-#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
-/*
- * Memory Hotadd without sparsemem. The mem_maps have been allocated in advance,
- * just online the pages.
- */
-int __add_pages(struct zone *z, unsigned long start_pfn, unsigned long nr_pages)
-{
- int err = -EIO;
- unsigned long pfn;
- unsigned long total = 0, mem = 0;
- for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) {
- if (pfn_valid(pfn)) {
- online_page(pfn_to_page(pfn));
- err = 0;
- mem++;
- }
- total++;
- }
- if (!err) {
- z->spanned_pages += total;
- z->present_pages += mem;
- z->zone_pgdat->node_spanned_pages += total;
- z->zone_pgdat->node_present_pages += mem;
- }
- return err;
-}
-#endif
-
static struct kcore_list kcore_mem, kcore_vmalloc, kcore_kernel, kcore_modules,
kcore_vsyscall;

@@ -739,7 +711,6 @@ const char *arch_vma_name(struct vm_area
return NULL;
}

-#ifdef CONFIG_SPARSEMEM_VMEMMAP
/*
* Initialise the sparsemem vmemmap using huge-pages at the PMD level.
*/
@@ -782,4 +753,3 @@ int __meminit vmemmap_populate(struct pa

return 0;
}
-#endif
Index: linux-2.6-x86/arch/x86/mm/srat_64.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/mm/srat_64.c 2007-11-26 13:53:18.983361973 -0800
+++ linux-2.6-x86/arch/x86/mm/srat_64.c 2007-11-26 15:15:41.434361980 -0800
@@ -151,62 +151,6 @@ acpi_numa_processor_affinity_init(struct
pxm, pa->apic_id, node);
}

-#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
-/*
- * Protect against too large hotadd areas that would fill up memory.
- */
-static int hotadd_enough_memory(struct bootnode *nd)
-{
- static unsigned long allocated;
- static unsigned long last_area_end;
- unsigned long pages = (nd->end - nd->start) >> PAGE_SHIFT;
- long mem = pages * sizeof(struct page);
- unsigned long addr;
- unsigned long allowed;
- unsigned long oldpages = pages;
-
- if (mem < 0)
- return 0;
- allowed = (end_pfn - absent_pages_in_range(0, end_pfn)) * PAGE_SIZE;
- allowed = (allowed / 100) * hotadd_percent;
- if (allocated + mem > allowed) {
- unsigned long range;
- /* Give them at least part of their hotadd memory upto hotadd_percent
- It would be better to spread the limit out
- over multiple hotplug areas, but that is too complicated
- right now */
- if (allocated >= allowed)
- return 0;
- range = allowed - allocated;
- pages = (range / PAGE_SIZE);
- mem = pages * sizeof(struct page);
- nd->end = nd->start + range;
- }
- /* Not completely fool proof, but a good sanity check */
- addr = find_e820_area(last_area_end, end_pfn<<PAGE_SHIFT, mem);
- if (addr == -1UL)
- return 0;
- if (pages != oldpages)
- printk(KERN_NOTICE "SRAT: Hotadd area limited to %lu bytes\n",
- pages << PAGE_SHIFT);
- last_area_end = addr + mem;
- allocated += mem;
- return 1;
-}
-
-static int update_end_of_memory(unsigned long end)
-{
- found_add_area = 1;
- if ((end >> PAGE_SHIFT) > end_pfn)
- end_pfn = end >> PAGE_SHIFT;
- return 1;
-}
-
-static inline int save_add_info(void)
-{
- return hotadd_percent > 0;
-}
-#else
int update_end_of_memory(unsigned long end) {return -1;}
static int hotadd_enough_memory(struct bootnode *nd) {return 1;}
#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
@@ -214,7 +158,6 @@ static inline int save_add_info(void) {r
#else
static inline int save_add_info(void) {return 0;}
#endif
-#endif
/*
* Update nodes_add and decide if to include add are in the zone.
* Both SPARSE and RESERVE need nodes_add infomation.
Index: linux-2.6-x86/arch/x86/Kconfig
===================================================================
--- linux-2.6-x86.orig/arch/x86/Kconfig 2007-11-26 15:15:25.194361726 -0800
+++ linux-2.6-x86/arch/x86/Kconfig 2007-11-26 15:17:40.310569645 -0800
@@ -912,25 +912,29 @@ config HAVE_ARCH_ALLOC_REMAP

config ARCH_FLATMEM_ENABLE
def_bool y
- depends on (X86_32 && ARCH_SELECT_MEMORY_MODEL && X86_PC) || (X86_64 && !NUMA)
+ depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && X86_PC

config ARCH_DISCONTIGMEM_ENABLE
def_bool y
- depends on NUMA
+ depends on NUMA && X86_32

config ARCH_DISCONTIGMEM_DEFAULT
def_bool y
- depends on NUMA
+ depends on NUMA && X86_32
+
+config ARCH_SPARSEMEM_DEFAULT
+ def_bool y
+ depends on X86_64

config ARCH_SPARSEMEM_ENABLE
def_bool y
- depends on NUMA || (EXPERIMENTAL && (X86_PC || X86_64))
+ depends on X86_64 || NUMA || (EXPERIMENTAL && X86_PC)
select SPARSEMEM_STATIC if X86_32
select SPARSEMEM_VMEMMAP_ENABLE if X86_64

config ARCH_SELECT_MEMORY_MODEL
def_bool y
- depends on X86_32 && ARCH_SPARSEMEM_ENABLE
+ depends on ARCH_SPARSEMEM_ENABLE

config ARCH_MEMORY_PROBE
def_bool X86_64
@@ -1228,18 +1232,10 @@ config ARCH_ENABLE_MEMORY_HOTPLUG
def_bool y
depends on X86_64 || (X86_32 && HIGHMEM)

-config MEMORY_HOTPLUG_RESERVE
- def_bool X86_64
- depends on (MEMORY_HOTPLUG && DISCONTIGMEM)
-
config HAVE_ARCH_EARLY_PFN_TO_NID
def_bool X86_64
depends on NUMA

-config OUT_OF_LINE_PFN_TO_PAGE
- def_bool X86_64
- depends on DISCONTIGMEM
-
menu "Power management options"
depends on !X86_VOYAGER


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