On 11/02/15 13:42, Jan Beulich wrote:
> Using atomic (LOCKed on x86) bitops for certain of the operations on
> cpumask_t is overkill when the variables aren't concurrently accessible
> (e.g. local function variables, or due to explicit locking). Introduce
> alternatives using non-atomic bitops and use them where appropriate.
>
> Note that this
> - adds a volatile qualifier to cpumask_test_and_{clear,set}_cpu()
> (should have been there from the beginning, like is the case for
> cpumask_{clear,set}_cpu())
> - replaces several cpumask_clear()+cpumask_set_cpu(, n) pairs by the
> simpler cpumask_copy(, cpumask_of(n)) (or just cpumask_of(n) if we
> can do without copying)
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
> Acked-by: George Dunlap <george.dun...@eu.citrix.com>
Reviewed-by: Andrew Cooper <andrew.coop...@citrix.com>
> ---
> v2: Make naming of new functions consistent with exisiting ones.
>
> --- a/xen/arch/x86/hpet.c
> +++ b/xen/arch/x86/hpet.c
> @@ -158,7 +158,7 @@ static void evt_do_broadcast(cpumask_t *
> {
> unsigned int cpu = smp_processor_id();
>
> - if ( cpumask_test_and_clear_cpu(cpu, mask) )
> + if ( __cpumask_test_and_clear_cpu(cpu, mask) )
> raise_softirq(TIMER_SOFTIRQ);
>
> cpuidle_wakeup_mwait(mask);
> @@ -197,7 +197,7 @@ again:
> continue;
>
> if ( deadline <= now )
> - cpumask_set_cpu(cpu, &mask);
> + __cpumask_set_cpu(cpu, &mask);
> else if ( deadline < next_event )
> next_event = deadline;
> }
> --- a/xen/arch/x86/irq.c
> +++ b/xen/arch/x86/irq.c
> @@ -1450,7 +1450,7 @@ void desc_guest_eoi(struct irq_desc *des
>
> cpumask_copy(&cpu_eoi_map, action->cpu_eoi_map);
>
> - if ( cpumask_test_and_clear_cpu(smp_processor_id(), &cpu_eoi_map) )
> + if ( __cpumask_test_and_clear_cpu(smp_processor_id(), &cpu_eoi_map) )
> {
> __set_eoi_ready(desc);
> spin_unlock(&desc->lock);
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -3216,7 +3216,7 @@ long do_mmuext_op(
> for_each_online_cpu(cpu)
> if ( !cpumask_intersects(&mask,
> per_cpu(cpu_sibling_mask, cpu))
> )
> - cpumask_set_cpu(cpu, &mask);
> + __cpumask_set_cpu(cpu, &mask);
> flush_mask(&mask, FLUSH_CACHE);
> }
> else
> --- a/xen/arch/x86/platform_hypercall.c
> +++ b/xen/arch/x86/platform_hypercall.c
> @@ -489,7 +489,7 @@ ret_t do_platform_op(XEN_GUEST_HANDLE_PA
>
> if ( !idletime )
> {
> - cpumask_clear_cpu(cpu, cpumap);
> + __cpumask_clear_cpu(cpu, cpumap);
> continue;
> }
>
> --- a/xen/arch/x86/time.c
> +++ b/xen/arch/x86/time.c
> @@ -179,7 +179,7 @@ static void smp_send_timer_broadcast_ipi
>
> if ( cpumask_test_cpu(cpu, &mask) )
> {
> - cpumask_clear_cpu(cpu, &mask);
> + __cpumask_clear_cpu(cpu, &mask);
> raise_softirq(TIMER_SOFTIRQ);
> }
>
> --- a/xen/common/core_parking.c
> +++ b/xen/common/core_parking.c
> @@ -75,11 +75,10 @@ static unsigned int core_parking_perform
> if ( core_weight < core_tmp )
> {
> core_weight = core_tmp;
> - cpumask_clear(&core_candidate_map);
> - cpumask_set_cpu(cpu, &core_candidate_map);
> + cpumask_copy(&core_candidate_map, cpumask_of(cpu));
> }
> else if ( core_weight == core_tmp )
> - cpumask_set_cpu(cpu, &core_candidate_map);
> + __cpumask_set_cpu(cpu, &core_candidate_map);
> }
>
> for_each_cpu(cpu, &core_candidate_map)
> @@ -88,11 +87,10 @@ static unsigned int core_parking_perform
> if ( sibling_weight < sibling_tmp )
> {
> sibling_weight = sibling_tmp;
> - cpumask_clear(&sibling_candidate_map);
> - cpumask_set_cpu(cpu, &sibling_candidate_map);
> + cpumask_copy(&sibling_candidate_map, cpumask_of(cpu));
> }
> else if ( sibling_weight == sibling_tmp )
> - cpumask_set_cpu(cpu, &sibling_candidate_map);
> + __cpumask_set_cpu(cpu, &sibling_candidate_map);
> }
>
> cpu = cpumask_first(&sibling_candidate_map);
> @@ -135,11 +133,10 @@ static unsigned int core_parking_power(u
> if ( core_weight > core_tmp )
> {
> core_weight = core_tmp;
> - cpumask_clear(&core_candidate_map);
> - cpumask_set_cpu(cpu, &core_candidate_map);
> + cpumask_copy(&core_candidate_map, cpumask_of(cpu));
> }
> else if ( core_weight == core_tmp )
> - cpumask_set_cpu(cpu, &core_candidate_map);
> + __cpumask_set_cpu(cpu, &core_candidate_map);
> }
>
> for_each_cpu(cpu, &core_candidate_map)
> @@ -148,11 +145,10 @@ static unsigned int core_parking_power(u
> if ( sibling_weight > sibling_tmp )
> {
> sibling_weight = sibling_tmp;
> - cpumask_clear(&sibling_candidate_map);
> - cpumask_set_cpu(cpu, &sibling_candidate_map);
> + cpumask_copy(&sibling_candidate_map, cpumask_of(cpu));
> }
> else if ( sibling_weight == sibling_tmp )
> - cpumask_set_cpu(cpu, &sibling_candidate_map);
> + __cpumask_set_cpu(cpu, &sibling_candidate_map);
> }
>
> cpu = cpumask_first(&sibling_candidate_map);
> --- a/xen/common/cpu.c
> +++ b/xen/common/cpu.c
> @@ -192,7 +192,7 @@ int disable_nonboot_cpus(void)
> break;
> }
>
> - cpumask_set_cpu(cpu, &frozen_cpus);
> + __cpumask_set_cpu(cpu, &frozen_cpus);
> }
>
> BUG_ON(!error && (num_online_cpus() != 1));
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -1337,7 +1337,7 @@ static int __init find_non_smt(unsigned
> if ( cpumask_intersects(dest, per_cpu(cpu_sibling_mask, i)) )
> continue;
> cpu = cpumask_first(per_cpu(cpu_sibling_mask, i));
> - cpumask_set_cpu(cpu, dest);
> + __cpumask_set_cpu(cpu, dest);
> }
> return cpumask_weight(dest);
> }
> @@ -1449,7 +1449,7 @@ void __init scrub_heap_pages(void)
> cpus = find_non_smt(best_node, &node_cpus);
> if ( cpus == 0 )
> {
> - cpumask_set_cpu(smp_processor_id(), &node_cpus);
> + __cpumask_set_cpu(smp_processor_id(), &node_cpus);
> cpus = 1;
> }
> /* We already have the node information from round #0. */
> --- a/xen/common/sched_credit.c
> +++ b/xen/common/sched_credit.c
> @@ -372,7 +372,7 @@ __runq_tickle(unsigned int cpu, struct c
> {
> if ( cur->pri != CSCHED_PRI_IDLE )
> SCHED_STAT_CRANK(tickle_idlers_none);
> - cpumask_set_cpu(cpu, &mask);
> + __cpumask_set_cpu(cpu, &mask);
> }
> else if ( !idlers_empty )
> {
> @@ -422,7 +422,7 @@ __runq_tickle(unsigned int cpu, struct c
> SCHED_VCPU_STAT_CRANK(cur, migrate_r);
> SCHED_STAT_CRANK(migrate_kicked_away);
> set_bit(_VPF_migrating, &cur->vcpu->pause_flags);
> - cpumask_set_cpu(cpu, &mask);
> + __cpumask_set_cpu(cpu, &mask);
> }
> else if ( !new_idlers_empty )
> {
> @@ -432,7 +432,7 @@ __runq_tickle(unsigned int cpu, struct c
> {
> this_cpu(last_tickle_cpu) =
> cpumask_cycle(this_cpu(last_tickle_cpu), &idle_mask);
> - cpumask_set_cpu(this_cpu(last_tickle_cpu), &mask);
> + __cpumask_set_cpu(this_cpu(last_tickle_cpu), &mask);
> }
> else
> cpumask_or(&mask, &mask, &idle_mask);
> @@ -675,7 +675,7 @@ _csched_cpu_pick(const struct scheduler
> */
> cpumask_and(&idlers, &cpu_online_map, CSCHED_PRIV(ops)->idlers);
> if ( vc->processor == cpu && IS_RUNQ_IDLE(cpu) )
> - cpumask_set_cpu(cpu, &idlers);
> + __cpumask_set_cpu(cpu, &idlers);
> cpumask_and(&cpus, &cpus, &idlers);
>
> /*
> @@ -692,7 +692,7 @@ _csched_cpu_pick(const struct scheduler
> */
> if ( !cpumask_test_cpu(cpu, &cpus) && !cpumask_empty(&cpus) )
> cpu = cpumask_cycle(cpu, &cpus);
> - cpumask_clear_cpu(cpu, &cpus);
> + __cpumask_clear_cpu(cpu, &cpus);
>
> while ( !cpumask_empty(&cpus) )
> {
> @@ -1536,7 +1536,7 @@ csched_load_balance(struct csched_privat
> /* Find out what the !idle are in this node */
> cpumask_andnot(&workers, online, prv->idlers);
> cpumask_and(&workers, &workers, &node_to_cpumask(peer_node));
> - cpumask_clear_cpu(cpu, &workers);
> + __cpumask_clear_cpu(cpu, &workers);
>
> peer_cpu = cpumask_first(&workers);
> if ( peer_cpu >= nr_cpu_ids )
> --- a/xen/common/sched_rt.c
> +++ b/xen/common/sched_rt.c
> @@ -663,7 +663,7 @@ burn_budget(const struct scheduler *ops,
> * lock is grabbed before calling this function
> */
> static struct rt_vcpu *
> -__runq_pick(const struct scheduler *ops, cpumask_t *mask)
> +__runq_pick(const struct scheduler *ops, const cpumask_t *mask)
> {
> struct list_head *runq = rt_runq(ops);
> struct list_head *iter;
> @@ -780,10 +780,7 @@ rt_schedule(const struct scheduler *ops,
> }
> else
> {
> - cpumask_t cur_cpu;
> - cpumask_clear(&cur_cpu);
> - cpumask_set_cpu(cpu, &cur_cpu);
> - snext = __runq_pick(ops, &cur_cpu);
> + snext = __runq_pick(ops, cpumask_of(cpu));
> if ( snext == NULL )
> snext = rt_vcpu(idle_vcpu[cpu]);
>
> --- a/xen/common/softirq.c
> +++ b/xen/common/softirq.c
> @@ -88,7 +88,7 @@ void cpumask_raise_softirq(const cpumask
> if ( !test_and_set_bit(nr, &softirq_pending(cpu)) &&
> cpu != this_cpu &&
> !arch_skip_send_event_check(cpu) )
> - cpumask_set_cpu(cpu, raise_mask);
> + __cpumask_set_cpu(cpu, raise_mask);
>
> if ( raise_mask == &send_mask )
> smp_send_event_check_mask(raise_mask);
> @@ -106,7 +106,7 @@ void cpu_raise_softirq(unsigned int cpu,
> if ( !per_cpu(batching, this_cpu) || in_irq() )
> smp_send_event_check_cpu(cpu);
> else
> - set_bit(nr, &per_cpu(batch_mask, this_cpu));
> + __cpumask_set_cpu(nr, &per_cpu(batch_mask, this_cpu));
> }
>
> void cpu_raise_softirq_batch_begin(void)
> @@ -122,7 +122,7 @@ void cpu_raise_softirq_batch_finish(void
> ASSERT(per_cpu(batching, this_cpu));
> for_each_cpu ( cpu, mask )
> if ( !softirq_pending(cpu) )
> - cpumask_clear_cpu(cpu, mask);
> + __cpumask_clear_cpu(cpu, mask);
> smp_send_event_check_mask(mask);
> cpumask_clear(mask);
> --per_cpu(batching, this_cpu);
> --- a/xen/include/xen/cpumask.h
> +++ b/xen/include/xen/cpumask.h
> @@ -103,11 +103,21 @@ static inline void cpumask_set_cpu(int c
> set_bit(cpumask_check(cpu), dstp->bits);
> }
>
> +static inline void __cpumask_set_cpu(int cpu, cpumask_t *dstp)
> +{
> + __set_bit(cpumask_check(cpu), dstp->bits);
> +}
> +
> static inline void cpumask_clear_cpu(int cpu, volatile cpumask_t *dstp)
> {
> clear_bit(cpumask_check(cpu), dstp->bits);
> }
>
> +static inline void __cpumask_clear_cpu(int cpu, cpumask_t *dstp)
> +{
> + __clear_bit(cpumask_check(cpu), dstp->bits);
> +}
> +
> static inline void cpumask_setall(cpumask_t *dstp)
> {
> bitmap_fill(dstp->bits, nr_cpumask_bits);
> @@ -122,16 +132,26 @@ static inline void cpumask_clear(cpumask
> #define cpumask_test_cpu(cpu, cpumask) \
> test_bit(cpumask_check(cpu), (cpumask)->bits)
>
> -static inline int cpumask_test_and_set_cpu(int cpu, cpumask_t *addr)
> +static inline int cpumask_test_and_set_cpu(int cpu, volatile cpumask_t *addr)
> {
> return test_and_set_bit(cpumask_check(cpu), addr->bits);
> }
>
> -static inline int cpumask_test_and_clear_cpu(int cpu, cpumask_t *addr)
> +static inline int __cpumask_test_and_set_cpu(int cpu, cpumask_t *addr)
> +{
> + return __test_and_set_bit(cpumask_check(cpu), addr->bits);
> +}
> +
> +static inline int cpumask_test_and_clear_cpu(int cpu, volatile cpumask_t
> *addr)
> {
> return test_and_clear_bit(cpumask_check(cpu), addr->bits);
> }
>
> +static inline int __cpumask_test_and_clear_cpu(int cpu, cpumask_t *addr)
> +{
> + return __test_and_clear_bit(cpumask_check(cpu), addr->bits);
> +}
> +
> static inline void cpumask_and(cpumask_t *dstp, const cpumask_t *src1p,
> const cpumask_t *src2p)
> {
>
>
>
>
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