aboutsummaryrefslogtreecommitdiffstats
path: root/kernel
diff options
context:
space:
mode:
authorRusty Russell <rusty@rustcorp.com.au>2008-11-04 21:39:10 -0500
committerIngo Molnar <mingo@elte.hu>2008-11-06 03:05:33 -0500
commit2d3854a37e8b767a51aba38ed6d22817b0631e33 (patch)
tree3b55cc93720b2e525460216b196ed20298ae985b /kernel
parent75fa67706cce5272bcfc51ed646f2da21f3bdb6e (diff)
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 <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpu.c3
-rw-r--r--kernel/workqueue.c45
2 files changed, 48 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 86d49045daed..5a732c5ef08b 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -499,3 +499,6 @@ const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
499#endif 499#endif
500}; 500};
501EXPORT_SYMBOL_GPL(cpu_bit_bitmap); 501EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
502
503const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
504EXPORT_SYMBOL(cpu_all_bits);
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f928f2a87b9b..d4dc69ddebd7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -970,6 +970,51 @@ undo:
970 return ret; 970 return ret;
971} 971}
972 972
973#ifdef CONFIG_SMP
974struct work_for_cpu {
975 struct work_struct work;
976 long (*fn)(void *);
977 void *arg;
978 long ret;
979};
980
981static void do_work_for_cpu(struct work_struct *w)
982{
983 struct work_for_cpu *wfc = container_of(w, struct work_for_cpu, work);
984
985 wfc->ret = wfc->fn(wfc->arg);
986}
987
988/**
989 * work_on_cpu - run a function in user context on a particular cpu
990 * @cpu: the cpu to run on
991 * @fn: the function to run
992 * @arg: the function arg
993 *
994 * This will return -EINVAL in the cpu is not online, or the return value
995 * of @fn otherwise.
996 */
997long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
998{
999 struct work_for_cpu wfc;
1000
1001 INIT_WORK(&wfc.work, do_work_for_cpu);
1002 wfc.fn = fn;
1003 wfc.arg = arg;
1004 get_online_cpus();
1005 if (unlikely(!cpu_online(cpu)))
1006 wfc.ret = -EINVAL;
1007 else {
1008 schedule_work_on(cpu, &wfc.work);
1009 flush_work(&wfc.work);
1010 }
1011 put_online_cpus();
1012
1013 return wfc.ret;
1014}
1015EXPORT_SYMBOL_GPL(work_on_cpu);
1016#endif /* CONFIG_SMP */
1017
973void __init init_workqueues(void) 1018void __init init_workqueues(void)
974{ 1019{
975 cpu_populated_map = cpu_online_map; 1020 cpu_populated_map = cpu_online_map;