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Date: Wed, 06 Mar 2013 15:50:20 -0600
From: Cliff Wickman <cpw@....com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org, x86@...nel.org, wli@...omorphy.com
Subject: [PATCH] mm, x86: no zeroing of hugetlbfs pages at boot
From: Cliff Wickman <cpw@....com>
Allocating a large number of 1GB hugetlbfs pages at boot takes a
very long time.
Large system sites would at times like to allocate a very large amount of
memory as 1GB pages. They would put this on the kernel boot line:
default_hugepagesz=1G hugepagesz=1G hugepages=4096
[Dynamic allocation of 1G pages is not an option, as zone pages only go
up to MAX_ORDER, and MAX_ORDER cannot exceed the section size.]
Each page is zeroed as it is allocated, and all allocation is done by
cpu 0, as this path is early in boot:
start_kernel
kernel_init
do_pre_smp_initcalls
hugetlb_init
hugetlb_init_hstates
hugetlb_hstate_alloc_pages
Zeroing remote (offnode) memory takes ~1GB/sec (and most memory is offnode
on large numa systems).
This estimate is approximate (it depends on core frequency & number of hops
to remote memory) but should be within a factor of 2 on most systems.
A benchmark attempting to reserve a TB for 1GB pages would thus require
~1000 seconds of boot time just for this allocating. 32TB would take 8 hours.
I propose passing a flag to the early allocator to indicate that no zeroing
of a page should be done. The 'no zeroing' flag would have to be passed
down this code path:
hugetlb_hstate_alloc_pages
alloc_bootmem_huge_page
__alloc_bootmem_node_nopanic NO_ZERO (nobootmem.c)
__alloc_memory_core_early NO_ZERO
if (!(flags & NO_ZERO))
memset(ptr, 0, size);
Or this path if CONFIG_NO_BOOTMEM is not set:
hugetlb_hstate_alloc_pages
alloc_bootmem_huge_page
__alloc_bootmem_node_nopanic NO_ZERO (bootmem.c)
alloc_bootmem_core NO_ZERO
if (!(flags & NO_ZERO))
memset(region, 0, size);
__alloc_bootmem_nopanic NO_ZERO
___alloc_bootmem_nopanic NO_ZERO
alloc_bootmem_core NO_ZERO
if (!(flags & NO_ZERO))
memset(region, 0, size);
Signed-off-by: Cliff Wickman <cpw@....com>
---
arch/x86/kernel/setup_percpu.c | 4 ++--
include/linux/bootmem.h | 23 ++++++++++++++++-------
mm/bootmem.c | 12 +++++++-----
mm/hugetlb.c | 3 ++-
mm/nobootmem.c | 41 +++++++++++++++++++++++------------------
mm/page_cgroup.c | 2 +-
mm/sparse.c | 2 +-
7 files changed, 52 insertions(+), 35 deletions(-)
Index: linux/include/linux/bootmem.h
===================================================================
--- linux.orig/include/linux/bootmem.h
+++ linux/include/linux/bootmem.h
@@ -8,6 +8,11 @@
#include <asm/dma.h>
/*
+ * allocation flags
+ */
+#define NO_ZERO 0x00000001
+
+/*
* simple boot-time physical memory area allocator.
*/
@@ -79,7 +84,8 @@ extern void *__alloc_bootmem(unsigned lo
unsigned long goal);
extern void *__alloc_bootmem_nopanic(unsigned long size,
unsigned long align,
- unsigned long goal);
+ unsigned long goal,
+ u32 flags);
extern void *__alloc_bootmem_node(pg_data_t *pgdat,
unsigned long size,
unsigned long align,
@@ -91,12 +97,14 @@ void *__alloc_bootmem_node_high(pg_data_
extern void *__alloc_bootmem_node_nopanic(pg_data_t *pgdat,
unsigned long size,
unsigned long align,
- unsigned long goal);
+ unsigned long goal,
+ u32 flags);
void *___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
unsigned long size,
unsigned long align,
unsigned long goal,
- unsigned long limit);
+ unsigned long limit,
+ u32 flags);
extern void *__alloc_bootmem_low(unsigned long size,
unsigned long align,
unsigned long goal);
@@ -120,19 +128,20 @@ extern void *__alloc_bootmem_low_node(pg
#define alloc_bootmem_align(x, align) \
__alloc_bootmem(x, align, BOOTMEM_LOW_LIMIT)
#define alloc_bootmem_nopanic(x) \
- __alloc_bootmem_nopanic(x, SMP_CACHE_BYTES, BOOTMEM_LOW_LIMIT)
+ __alloc_bootmem_nopanic(x, SMP_CACHE_BYTES, BOOTMEM_LOW_LIMIT, 0)
#define alloc_bootmem_pages(x) \
__alloc_bootmem(x, PAGE_SIZE, BOOTMEM_LOW_LIMIT)
#define alloc_bootmem_pages_nopanic(x) \
- __alloc_bootmem_nopanic(x, PAGE_SIZE, BOOTMEM_LOW_LIMIT)
+ __alloc_bootmem_nopanic(x, PAGE_SIZE, BOOTMEM_LOW_LIMIT, 0)
#define alloc_bootmem_node(pgdat, x) \
__alloc_bootmem_node(pgdat, x, SMP_CACHE_BYTES, BOOTMEM_LOW_LIMIT)
#define alloc_bootmem_node_nopanic(pgdat, x) \
- __alloc_bootmem_node_nopanic(pgdat, x, SMP_CACHE_BYTES, BOOTMEM_LOW_LIMIT)
+ __alloc_bootmem_node_nopanic(pgdat, x, SMP_CACHE_BYTES, \
+ BOOTMEM_LOW_LIMIT, 0)
#define alloc_bootmem_pages_node(pgdat, x) \
__alloc_bootmem_node(pgdat, x, PAGE_SIZE, BOOTMEM_LOW_LIMIT)
#define alloc_bootmem_pages_node_nopanic(pgdat, x) \
- __alloc_bootmem_node_nopanic(pgdat, x, PAGE_SIZE, BOOTMEM_LOW_LIMIT)
+ __alloc_bootmem_node_nopanic(pgdat, x, PAGE_SIZE, BOOTMEM_LOW_LIMIT, 0)
#define alloc_bootmem_low(x) \
__alloc_bootmem_low(x, SMP_CACHE_BYTES, 0)
Index: linux/arch/x86/kernel/setup_percpu.c
===================================================================
--- linux.orig/arch/x86/kernel/setup_percpu.c
+++ linux/arch/x86/kernel/setup_percpu.c
@@ -104,14 +104,14 @@ static void * __init pcpu_alloc_bootmem(
void *ptr;
if (!node_online(node) || !NODE_DATA(node)) {
- ptr = __alloc_bootmem_nopanic(size, align, goal);
+ ptr = __alloc_bootmem_nopanic(size, align, goal, 0);
pr_info("cpu %d has no node %d or node-local memory\n",
cpu, node);
pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
cpu, size, __pa(ptr));
} else {
ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
- size, align, goal);
+ size, align, goal, 0);
pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n",
cpu, size, node, __pa(ptr));
}
Index: linux/mm/nobootmem.c
===================================================================
--- linux.orig/mm/nobootmem.c
+++ linux/mm/nobootmem.c
@@ -33,7 +33,7 @@ unsigned long min_low_pfn;
unsigned long max_pfn;
static void * __init __alloc_memory_core_early(int nid, u64 size, u64 align,
- u64 goal, u64 limit)
+ u64 goal, u64 limit, u32 flags)
{
void *ptr;
u64 addr;
@@ -46,7 +46,8 @@ static void * __init __alloc_memory_core
return NULL;
ptr = phys_to_virt(addr);
- memset(ptr, 0, size);
+ if (!(flags & NO_ZERO))
+ memset(ptr, 0, size);
memblock_reserve(addr, size);
/*
* The min_count is set to 0 so that bootmem allocated blocks
@@ -208,7 +209,8 @@ void __init free_bootmem(unsigned long a
static void * __init ___alloc_bootmem_nopanic(unsigned long size,
unsigned long align,
unsigned long goal,
- unsigned long limit)
+ unsigned long limit,
+ u32 flags)
{
void *ptr;
@@ -217,7 +219,8 @@ static void * __init ___alloc_bootmem_no
restart:
- ptr = __alloc_memory_core_early(MAX_NUMNODES, size, align, goal, limit);
+ ptr = __alloc_memory_core_early(MAX_NUMNODES, size, align, goal,
+ limit, 0);
if (ptr)
return ptr;
@@ -244,17 +247,17 @@ restart:
* Returns NULL on failure.
*/
void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
- unsigned long goal)
+ unsigned long goal, u32 flags)
{
unsigned long limit = -1UL;
- return ___alloc_bootmem_nopanic(size, align, goal, limit);
+ return ___alloc_bootmem_nopanic(size, align, goal, limit, flags);
}
static void * __init ___alloc_bootmem(unsigned long size, unsigned long align,
- unsigned long goal, unsigned long limit)
+ unsigned long goal, unsigned long limit, u32 flags)
{
- void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit);
+ void *mem = ___alloc_bootmem_nopanic(size, align, goal, limit, flags);
if (mem)
return mem;
@@ -284,25 +287,26 @@ void * __init __alloc_bootmem(unsigned l
{
unsigned long limit = -1UL;
- return ___alloc_bootmem(size, align, goal, limit);
+ return ___alloc_bootmem(size, align, goal, limit, 0);
}
void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
unsigned long size,
unsigned long align,
unsigned long goal,
- unsigned long limit)
+ unsigned long limit,
+ u32 flags)
{
void *ptr;
again:
ptr = __alloc_memory_core_early(pgdat->node_id, size, align,
- goal, limit);
+ goal, limit, flags);
if (ptr)
return ptr;
ptr = __alloc_memory_core_early(MAX_NUMNODES, size, align,
- goal, limit);
+ goal, limit, flags);
if (ptr)
return ptr;
@@ -315,12 +319,13 @@ again:
}
void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
- unsigned long align, unsigned long goal)
+ unsigned long align, unsigned long goal, u32 flags)
{
if (WARN_ON_ONCE(slab_is_available()))
return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
- return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
+ return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal,
+ 0, flags);
}
void * __init ___alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
@@ -329,7 +334,7 @@ void * __init ___alloc_bootmem_node(pg_d
{
void *ptr;
- ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, limit);
+ ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, limit, 0);
if (ptr)
return ptr;
@@ -354,7 +359,7 @@ void * __init ___alloc_bootmem_node(pg_d
* The function panics if the request can not be satisfied.
*/
void * __init __alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
- unsigned long align, unsigned long goal)
+ unsigned long align, unsigned long goal)
{
if (WARN_ON_ONCE(slab_is_available()))
return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
@@ -388,7 +393,7 @@ void * __init __alloc_bootmem_node_high(
void * __init __alloc_bootmem_low(unsigned long size, unsigned long align,
unsigned long goal)
{
- return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT);
+ return ___alloc_bootmem(size, align, goal, ARCH_LOW_ADDRESS_LIMIT, 0);
}
void * __init __alloc_bootmem_low_nopanic(unsigned long size,
@@ -396,7 +401,7 @@ void * __init __alloc_bootmem_low_nopani
unsigned long goal)
{
return ___alloc_bootmem_nopanic(size, align, goal,
- ARCH_LOW_ADDRESS_LIMIT);
+ ARCH_LOW_ADDRESS_LIMIT, 0);
}
/**
Index: linux/mm/sparse.c
===================================================================
--- linux.orig/mm/sparse.c
+++ linux/mm/sparse.c
@@ -281,7 +281,7 @@ sparse_early_usemaps_alloc_pgdat_section
nid = early_pfn_to_nid(goal >> PAGE_SHIFT);
again:
p = ___alloc_bootmem_node_nopanic(NODE_DATA(nid), size,
- SMP_CACHE_BYTES, goal, limit);
+ SMP_CACHE_BYTES, goal, limit, 0);
if (!p && limit) {
limit = 0;
goto again;
Index: linux/mm/hugetlb.c
===================================================================
--- linux.orig/mm/hugetlb.c
+++ linux/mm/hugetlb.c
@@ -1188,7 +1188,8 @@ int __weak alloc_bootmem_huge_page(struc
addr = __alloc_bootmem_node_nopanic(
NODE_DATA(hstate_next_node_to_alloc(h,
&node_states[N_MEMORY])),
- huge_page_size(h), huge_page_size(h), 0);
+ huge_page_size(h), huge_page_size(h),
+ 0, NO_ZERO);
if (addr) {
/*
Index: linux/mm/bootmem.c
===================================================================
--- linux.orig/mm/bootmem.c
+++ linux/mm/bootmem.c
@@ -660,7 +660,7 @@ restart:
* Returns NULL on failure.
*/
void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align,
- unsigned long goal)
+ unsigned long goal, u32 flags)
{
unsigned long limit = 0;
@@ -705,7 +705,8 @@ void * __init __alloc_bootmem(unsigned l
void * __init ___alloc_bootmem_node_nopanic(pg_data_t *pgdat,
unsigned long size, unsigned long align,
- unsigned long goal, unsigned long limit)
+ unsigned long goal, unsigned long limit,
+ u32 flags)
{
void *ptr;
@@ -734,12 +735,13 @@ again:
}
void * __init __alloc_bootmem_node_nopanic(pg_data_t *pgdat, unsigned long size,
- unsigned long align, unsigned long goal)
+ unsigned long align, unsigned long goal, u32 flags)
{
if (WARN_ON_ONCE(slab_is_available()))
return kzalloc_node(size, GFP_NOWAIT, pgdat->node_id);
- return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
+ return ___alloc_bootmem_node_nopanic(pgdat, size, align, goal,
+ 0, flags);
}
void * __init ___alloc_bootmem_node(pg_data_t *pgdat, unsigned long size,
@@ -748,7 +750,7 @@ void * __init ___alloc_bootmem_node(pg_d
{
void *ptr;
- ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0);
+ ptr = ___alloc_bootmem_node_nopanic(pgdat, size, align, goal, 0, 0);
if (ptr)
return ptr;
Index: linux/mm/page_cgroup.c
===================================================================
--- linux.orig/mm/page_cgroup.c
+++ linux/mm/page_cgroup.c
@@ -55,7 +55,7 @@ static int __init alloc_node_page_cgroup
table_size = sizeof(struct page_cgroup) * nr_pages;
base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
- table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
+ table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS), 0);
if (!base)
return -ENOMEM;
NODE_DATA(nid)->node_page_cgroup = base;
--
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