From 2d3854a37e8b767a51aba38ed6d22817b0631e33 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 5 Nov 2008 13:39:10 +1100 Subject: cpumask: introduce new API, without changing anything Impact: introduce new APIs We want to deprecate cpumasks on the stack, as we are headed for gynormous numbers of CPUs. Eventually, we want to head towards an undefined 'struct cpumask' so they can never be declared on stack. 1) New cpumask functions which take pointers instead of copies. (cpus_* -> cpumask_*) 2) Several new helpers to reduce requirements for temporary cpumasks (cpumask_first_and, cpumask_next_and, cpumask_any_and) 3) Helpers for declaring cpumasks on or offstack for large NR_CPUS (cpumask_var_t, alloc_cpumask_var and free_cpumask_var) 4) 'struct cpumask' for explicitness and to mark new-style code. 5) Make iterator functions stop at nr_cpu_ids (a runtime constant), not NR_CPUS for time efficiency and for smaller dynamic allocations in future. 6) cpumask_copy() so we can allocate less than a full cpumask eventually (for alloc_cpumask_var), and so we can eliminate the 'struct cpumask' definition eventually. 7) work_on_cpu() helper for doing task on a CPU, rather than saving old cpumask for current thread and manipulating it. 8) smp_call_function_many() which is smp_call_function_mask() except taking a cpumask pointer. Note that this patch simply introduces the new functions and leaves the obsolescent ones in place. This is to simplify the transition patches. Signed-off-by: Rusty Russell Signed-off-by: Ingo Molnar --- lib/cpumask.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) (limited to 'lib') diff --git a/lib/cpumask.c b/lib/cpumask.c index 5f97dc25ef9c..5ceb4211c834 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -2,6 +2,7 @@ #include #include #include +#include int __first_cpu(const cpumask_t *srcp) { @@ -35,3 +36,75 @@ int __any_online_cpu(const cpumask_t *mask) return cpu; } EXPORT_SYMBOL(__any_online_cpu); + +/** + * cpumask_next_and - get the next cpu in *src1p & *src2p + * @n: the cpu prior to the place to search (ie. return will be > @n) + * @src1p: the first cpumask pointer + * @src2p: the second cpumask pointer + * + * Returns >= nr_cpu_ids if no further cpus set in both. + */ +int cpumask_next_and(int n, const struct cpumask *src1p, + const struct cpumask *src2p) +{ + while ((n = cpumask_next(n, src1p)) < nr_cpu_ids) + if (cpumask_test_cpu(n, src2p)) + break; + return n; +} +EXPORT_SYMBOL(cpumask_next_and); + +/** + * cpumask_any_but - return a "random" in a cpumask, but not this one. + * @mask: the cpumask to search + * @cpu: the cpu to ignore. + * + * Often used to find any cpu but smp_processor_id() in a mask. + * Returns >= nr_cpu_ids if no cpus set. + */ +int cpumask_any_but(const struct cpumask *mask, unsigned int cpu) +{ + unsigned int i; + + for_each_cpu(i, mask) + if (i != cpu) + break; + return i; +} + +/* These are not inline because of header tangles. */ +#ifdef CONFIG_CPUMASK_OFFSTACK +bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) +{ + if (likely(slab_is_available())) + *mask = kmalloc(cpumask_size(), flags); + else { +#ifdef CONFIG_DEBUG_PER_CPU_MAPS + printk(KERN_ERR + "=> alloc_cpumask_var: kmalloc not available!\n"); + dump_stack(); +#endif + *mask = NULL; + } +#ifdef CONFIG_DEBUG_PER_CPU_MAPS + if (!*mask) { + printk(KERN_ERR "=> alloc_cpumask_var: failed!\n"); + dump_stack(); + } +#endif + return *mask != NULL; +} +EXPORT_SYMBOL(alloc_cpumask_var); + +void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask) +{ + *mask = alloc_bootmem(cpumask_size()); +} + +void free_cpumask_var(cpumask_var_t mask) +{ + kfree(mask); +} +EXPORT_SYMBOL(free_cpumask_var); +#endif -- cgit v1.2.3 From cd83e42c6b0413dcbb548c2ead799111ff7e6a13 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 7 Nov 2008 11:12:29 +1100 Subject: cpumask: new API, v2 - add cpumask_of() - add free_bootmem_cpumask_var() Signed-off-by: Rusty Russell Signed-off-by: Ingo Molnar --- include/linux/cpumask.h | 11 +++++++++++ lib/cpumask.c | 5 +++++ 2 files changed, 16 insertions(+) (limited to 'lib') diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index c8e66619097b..31caa1bc620a 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -893,6 +893,12 @@ static inline void cpumask_copy(struct cpumask *dstp, */ #define cpumask_any_and(mask1, mask2) cpumask_first_and((mask1), (mask2)) +/** + * cpumask_of - the cpumask containing just a given cpu + * @cpu: the cpu (<= nr_cpu_ids) + */ +#define cpumask_of(cpu) (get_cpu_mask(cpu)) + /** * to_cpumask - convert an NR_CPUS bitmap to a struct cpumask * * @bitmap: the bitmap @@ -946,6 +952,7 @@ typedef struct cpumask *cpumask_var_t; bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags); void alloc_bootmem_cpumask_var(cpumask_var_t *mask); void free_cpumask_var(cpumask_var_t mask); +void free_bootmem_cpumask_var(cpumask_var_t mask); #else typedef struct cpumask cpumask_var_t[1]; @@ -962,6 +969,10 @@ static inline void alloc_bootmem_cpumask_var(cpumask_var_t *mask) static inline void free_cpumask_var(cpumask_var_t mask) { } + +static inline void free_bootmem_cpumask_var(cpumask_var_t mask) +{ +} #endif /* CONFIG_CPUMASK_OFFSTACK */ /* The pointer versions of the maps, these will become the primary versions. */ diff --git a/lib/cpumask.c b/lib/cpumask.c index 5ceb4211c834..2ebc3a9a7465 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -107,4 +107,9 @@ void free_cpumask_var(cpumask_var_t mask) kfree(mask); } EXPORT_SYMBOL(free_cpumask_var); + +void free_bootmem_cpumask_var(cpumask_var_t mask) +{ + free_bootmem((unsigned long)mask, cpumask_size()); +} #endif -- cgit v1.2.3 From 984f2f377fdfd098f5ae58d09ee04d5e29e6112b Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Sat, 8 Nov 2008 20:24:19 +1100 Subject: cpumask: introduce new API, without changing anything, v3 Impact: cleanup Clean up based on feedback from Andrew Morton and others: - change to inline functions instead of macros - add __init to bootmem method - add a missing debug check Signed-off-by: Rusty Russell Signed-off-by: Ingo Molnar --- include/linux/cpumask.h | 58 ++++++++++++++++++++++++++++++++++++++++++++----- lib/cpumask.c | 3 ++- 2 files changed, 54 insertions(+), 7 deletions(-) (limited to 'lib') diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 31caa1bc620a..21e1dd43e52a 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -564,12 +564,36 @@ static inline unsigned int cpumask_check(unsigned int cpu) } #if NR_CPUS == 1 -/* Uniprocesor. */ -#define cpumask_first(src) ({ (void)(src); 0; }) -#define cpumask_next(n, src) ({ (void)(src); 1; }) -#define cpumask_next_zero(n, src) ({ (void)(src); 1; }) -#define cpumask_next_and(n, srcp, andp) ({ (void)(srcp), (void)(andp); 1; }) -#define cpumask_any_but(mask, cpu) ({ (void)(mask); (void)(cpu); 0; }) +/* Uniprocessor. Assume all masks are "1". */ +static inline unsigned int cpumask_first(const struct cpumask *srcp) +{ + return 0; +} + +/* Valid inputs for n are -1 and 0. */ +static inline unsigned int cpumask_next(int n, const struct cpumask *srcp) +{ + return n+1; +} + +static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp) +{ + return n+1; +} + +static inline unsigned int cpumask_next_and(int n, + const struct cpumask *srcp, + const struct cpumask *andp) +{ + return n+1; +} + +/* cpu must be a valid cpu, ie 0, so there's no other choice. */ +static inline unsigned int cpumask_any_but(const struct cpumask *mask, + unsigned int cpu) +{ + return 1; +} #define for_each_cpu(cpu, mask) \ for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask) @@ -620,10 +644,32 @@ static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp) int cpumask_next_and(int n, const struct cpumask *, const struct cpumask *); int cpumask_any_but(const struct cpumask *mask, unsigned int cpu); +/** + * for_each_cpu - iterate over every cpu in a mask + * @cpu: the (optionally unsigned) integer iterator + * @mask: the cpumask pointer + * + * After the loop, cpu is >= nr_cpu_ids. + */ #define for_each_cpu(cpu, mask) \ for ((cpu) = -1; \ (cpu) = cpumask_next((cpu), (mask)), \ (cpu) < nr_cpu_ids;) + +/** + * for_each_cpu_and - iterate over every cpu in both masks + * @cpu: the (optionally unsigned) integer iterator + * @mask: the first cpumask pointer + * @and: the second cpumask pointer + * + * This saves a temporary CPU mask in many places. It is equivalent to: + * struct cpumask tmp; + * cpumask_and(&tmp, &mask, &and); + * for_each_cpu(cpu, &tmp) + * ... + * + * After the loop, cpu is >= nr_cpu_ids. + */ #define for_each_cpu_and(cpu, mask, and) \ for ((cpu) = -1; \ (cpu) = cpumask_next_and((cpu), (mask), (and)), \ diff --git a/lib/cpumask.c b/lib/cpumask.c index 2ebc3a9a7465..8d03f22c6ced 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -67,6 +67,7 @@ int cpumask_any_but(const struct cpumask *mask, unsigned int cpu) { unsigned int i; + cpumask_check(cpu); for_each_cpu(i, mask) if (i != cpu) break; @@ -108,7 +109,7 @@ void free_cpumask_var(cpumask_var_t mask) } EXPORT_SYMBOL(free_cpumask_var); -void free_bootmem_cpumask_var(cpumask_var_t mask) +void __init free_bootmem_cpumask_var(cpumask_var_t mask) { free_bootmem((unsigned long)mask, cpumask_size()); } -- cgit v1.2.3