From 6a242909b01120f6f3d571c0b75e20ec61f0d8d3 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 6 Mar 2009 14:33:58 +0900 Subject: percpu: clean up percpu constants Impact: cleaup Make the following cleanups. * There isn't much arch-specific about PERCPU_MODULE_RESERVE. Always define it whether arch overrides PERCPU_ENOUGH_ROOM or not. * blackfin overrides PERCPU_ENOUGH_ROOM to align static area size. Do it by default. * percpu allocation sizes doesn't have much to do with the page size. Don't use PAGE_SHIFT in their definition. Signed-off-by: Tejun Heo Cc: Bryan Wu --- include/linux/percpu.h | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) (limited to 'include') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 545b068..2d34b03 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -5,6 +5,7 @@ #include /* For kmalloc() */ #include #include +#include #include @@ -52,17 +53,18 @@ #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var) #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var) -/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */ -#ifndef PERCPU_ENOUGH_ROOM +/* enough to cover all DEFINE_PER_CPUs in modules */ #ifdef CONFIG_MODULES -#define PERCPU_MODULE_RESERVE 8192 +#define PERCPU_MODULE_RESERVE (8 << 10) #else -#define PERCPU_MODULE_RESERVE 0 +#define PERCPU_MODULE_RESERVE 0 #endif +#ifndef PERCPU_ENOUGH_ROOM #define PERCPU_ENOUGH_ROOM \ - (__per_cpu_end - __per_cpu_start + PERCPU_MODULE_RESERVE) -#endif /* PERCPU_ENOUGH_ROOM */ + (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \ + PERCPU_MODULE_RESERVE) +#endif /* * Must be an lvalue. Since @var must be a simple identifier, @@ -79,7 +81,7 @@ #ifdef CONFIG_HAVE_DYNAMIC_PER_CPU_AREA /* minimum unit size, also is the maximum supported allocation size */ -#define PCPU_MIN_UNIT_SIZE (16UL << PAGE_SHIFT) +#define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10) /* * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy @@ -96,15 +98,15 @@ #ifndef PERCPU_DYNAMIC_RESERVE # if BITS_PER_LONG > 32 # ifdef CONFIG_MODULES -# define PERCPU_DYNAMIC_RESERVE (6 << PAGE_SHIFT) +# define PERCPU_DYNAMIC_RESERVE (24 << 10) # else -# define PERCPU_DYNAMIC_RESERVE (4 << PAGE_SHIFT) +# define PERCPU_DYNAMIC_RESERVE (16 << 10) # endif # else # ifdef CONFIG_MODULES -# define PERCPU_DYNAMIC_RESERVE (4 << PAGE_SHIFT) +# define PERCPU_DYNAMIC_RESERVE (16 << 10) # else -# define PERCPU_DYNAMIC_RESERVE (2 << PAGE_SHIFT) +# define PERCPU_DYNAMIC_RESERVE (8 << 10) # endif # endif #endif /* PERCPU_DYNAMIC_RESERVE */ -- cgit v1.1 From 2441d15c97d498b18f03ae9fba262ffeae42a08b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 6 Mar 2009 14:33:59 +0900 Subject: percpu: cosmetic renames in pcpu_setup_first_chunk() Impact: cosmetic, preparation for future changes Make the following renames in pcpur_setup_first_chunk() in preparation for future changes. * s/free_size/dyn_size/ * s/static_vm/first_vm/ * s/static_chunk/schunk/ Signed-off-by: Tejun Heo --- include/linux/percpu.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 2d34b03..a0b4ea2 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -118,7 +118,7 @@ typedef void (*pcpu_populate_pte_fn_t)(unsigned long addr); extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, size_t static_size, size_t unit_size, - size_t free_size, void *base_addr, + size_t dyn_size, void *base_addr, pcpu_populate_pte_fn_t populate_pte_fn); /* -- cgit v1.1 From cafe8816b217b98dc3f268d3b77445da498beb4f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 6 Mar 2009 14:33:59 +0900 Subject: percpu: use negative for auto for pcpu_setup_first_chunk() arguments Impact: argument semantic cleanup In pcpu_setup_first_chunk(), zero @unit_size and @dyn_size meant auto-sizing. It's okay for @unit_size as 0 doesn't make sense but 0 dynamic reserve size is valid. Alos, if arch @dyn_size is calculated from other parameters, it might end up passing in 0 @dyn_size and malfunction when the size is automatically adjusted. This patch makes both @unit_size and @dyn_size ssize_t and use -1 for auto sizing. Signed-off-by: Tejun Heo --- include/linux/percpu.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index a0b4ea2..a96fc53 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -117,8 +117,9 @@ typedef struct page * (*pcpu_get_page_fn_t)(unsigned int cpu, int pageno); typedef void (*pcpu_populate_pte_fn_t)(unsigned long addr); extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, - size_t static_size, size_t unit_size, - size_t dyn_size, void *base_addr, + size_t static_size, + ssize_t unit_size, ssize_t dyn_size, + void *base_addr, pcpu_populate_pte_fn_t populate_pte_fn); /* -- cgit v1.1 From edcb463997ed7b2ffa3bac76e3e75957318f2e01 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 6 Mar 2009 14:33:59 +0900 Subject: percpu, module: implement reserved allocation and use it for module percpu variables Impact: add reserved allocation functionality and use it for module percpu variables This patch implements reserved allocation from the first chunk. When setting up the first chunk, arch can ask to set aside certain number of bytes right after the core static area which is available only through a separate reserved allocator. This will be used primarily for module static percpu variables on architectures with limited relocation range to ensure that the module perpcu symbols are inside the relocatable range. If reserved area is requested, the first chunk becomes reserved and isn't available for regular allocation. If the first chunk also includes piggy-back dynamic allocation area, a separate chunk mapping the same region is created to serve dynamic allocation. The first one is called static first chunk and the second dynamic first chunk. Although they share the page map, their different area map initializations guarantee they serve disjoint areas according to their purposes. If arch doesn't setup reserved area, reserved allocation is handled like any other allocation. Signed-off-by: Tejun Heo --- include/linux/percpu.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index a96fc53..8ff1515 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -117,10 +117,10 @@ typedef struct page * (*pcpu_get_page_fn_t)(unsigned int cpu, int pageno); typedef void (*pcpu_populate_pte_fn_t)(unsigned long addr); extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, - size_t static_size, - ssize_t unit_size, ssize_t dyn_size, - void *base_addr, - pcpu_populate_pte_fn_t populate_pte_fn); + size_t static_size, size_t reserved_size, + ssize_t unit_size, ssize_t dyn_size, + void *base_addr, + pcpu_populate_pte_fn_t populate_pte_fn); /* * Use this to get to a cpu's version of the per-cpu object @@ -129,6 +129,8 @@ extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, */ #define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu))) +extern void *__alloc_reserved_percpu(size_t size, size_t align); + #else /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */ struct percpu_data { -- cgit v1.1 From 6b19b0c2400437a3c10059ede0e59b517092e1bd Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 6 Mar 2009 14:33:59 +0900 Subject: x86, percpu: setup reserved percpu area for x86_64 Impact: fix relocation overflow during module load x86_64 uses 32bit relocations for symbol access and static percpu symbols whether in core or modules must be inside 2GB of the percpu segement base which the dynamic percpu allocator doesn't guarantee. This patch makes x86_64 reserve PERCPU_MODULE_RESERVE bytes in the first chunk so that module percpu areas are always allocated from the first chunk which is always inside the relocatable range. This problem exists for any percpu allocator but is easily triggered when using the embedding allocator because the second chunk is located beyond 2GB on it. This patch also changes the meaning of PERCPU_DYNAMIC_RESERVE such that it only indicates the size of the area to reserve for dynamic allocation as static and dynamic areas can be separate. New PERCPU_DYNAMIC_RESERVED is increased by 4k for both 32 and 64bits as the reserved area separation eats away some allocatable space and having slightly more headroom (currently between 4 and 8k after minimal boot sans module area) makes sense for common case performance. x86_32 can address anywhere from anywhere and doesn't need reserving. Mike Galbraith first reported the problem first and bisected it to the embedding percpu allocator commit. Signed-off-by: Tejun Heo Reported-by: Mike Galbraith Reported-by: Jaswinder Singh Rajput --- include/linux/percpu.h | 35 ++++++++++++----------------------- 1 file changed, 12 insertions(+), 23 deletions(-) (limited to 'include') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 8ff1515..54a968b 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -85,31 +85,20 @@ /* * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy - * back on the first chunk if arch is manually allocating and mapping - * it for faster access (as a part of large page mapping for example). - * Note that dynamic percpu allocator covers both static and dynamic - * areas, so these values are bigger than PERCPU_MODULE_RESERVE. + * back on the first chunk for dynamic percpu allocation if arch is + * manually allocating and mapping it for faster access (as a part of + * large page mapping for example). * - * On typical configuration with modules, the following values leave - * about 8k of free space on the first chunk after boot on both x86_32 - * and 64 when module support is enabled. When module support is - * disabled, it's much tighter. + * The following values give between one and two pages of free space + * after typical minimal boot (2-way SMP, single disk and NIC) with + * both defconfig and a distro config on x86_64 and 32. More + * intelligent way to determine this would be nice. */ -#ifndef PERCPU_DYNAMIC_RESERVE -# if BITS_PER_LONG > 32 -# ifdef CONFIG_MODULES -# define PERCPU_DYNAMIC_RESERVE (24 << 10) -# else -# define PERCPU_DYNAMIC_RESERVE (16 << 10) -# endif -# else -# ifdef CONFIG_MODULES -# define PERCPU_DYNAMIC_RESERVE (16 << 10) -# else -# define PERCPU_DYNAMIC_RESERVE (8 << 10) -# endif -# endif -#endif /* PERCPU_DYNAMIC_RESERVE */ +#if BITS_PER_LONG > 32 +#define PERCPU_DYNAMIC_RESERVE (20 << 10) +#else +#define PERCPU_DYNAMIC_RESERVE (12 << 10) +#endif extern void *pcpu_base_addr; -- cgit v1.1