* [PATCH 39/49] arch/s390: replace cpumask_weight with cpumask_weight_eq where appropriate [not found] <20220210224933.379149-1-yury.norov@gmail.com> @ 2022-02-10 22:49 ` Yury Norov 2022-02-11 6:54 ` Sven Schnelle 0 siblings, 1 reply; 3+ messages in thread From: Yury Norov @ 2022-02-10 22:49 UTC (permalink / raw) To: Yury Norov, Andy Shevchenko, Rasmus Villemoes, Andrew Morton, Michał Mirosław, Greg Kroah-Hartman, Peter Zijlstra, David Laight, Joe Perches, Dennis Zhou, Emil Renner Berthing, Nicholas Piggin, Matti Vaittinen, Alexey Klimov, linux-kernel, Heiko Carstens, Vasily Gorbik, Christian Borntraeger, Alexander Gordeev, Sven Schnelle, Thomas Richter, Sumanth Korikkar, Sebastian Andrzej Siewior, Jiapeng Chong, kernel test robot, linux-s390 cfset_all_start() calls cpumask_weight() to compare the weight of cpumask with a given number. We can do it more efficiently with cpumask_weight_{eq, ...} because conditional cpumask_weight may stop traversing the cpumask earlier, as soon as condition is (or can't be) met. Signed-off-by: Yury Norov <yury.norov@gmail.com> --- arch/s390/kernel/perf_cpum_cf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c index ee8707abdb6a..4d217f7f5ccf 100644 --- a/arch/s390/kernel/perf_cpum_cf.c +++ b/arch/s390/kernel/perf_cpum_cf.c @@ -975,7 +975,7 @@ static int cfset_all_start(struct cfset_request *req) return -ENOMEM; cpumask_and(mask, &req->mask, cpu_online_mask); on_each_cpu_mask(mask, cfset_ioctl_on, &p, 1); - if (atomic_read(&p.cpus_ack) != cpumask_weight(mask)) { + if (!cpumask_weight_eq(mask, atomic_read(&p.cpus_ack))) { on_each_cpu_mask(mask, cfset_ioctl_off, &p, 1); rc = -EIO; debug_sprintf_event(cf_dbg, 4, "%s CPUs missing", __func__); -- 2.32.0 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 39/49] arch/s390: replace cpumask_weight with cpumask_weight_eq where appropriate 2022-02-10 22:49 ` [PATCH 39/49] arch/s390: replace cpumask_weight with cpumask_weight_eq where appropriate Yury Norov @ 2022-02-11 6:54 ` Sven Schnelle 2022-02-11 23:40 ` Yury Norov 0 siblings, 1 reply; 3+ messages in thread From: Sven Schnelle @ 2022-02-11 6:54 UTC (permalink / raw) To: Yury Norov Cc: Andy Shevchenko, Rasmus Villemoes, Andrew Morton, Michał Mirosław, Greg Kroah-Hartman, Peter Zijlstra, David Laight, Joe Perches, Dennis Zhou, Emil Renner Berthing, Nicholas Piggin, Matti Vaittinen, Alexey Klimov, linux-kernel, Heiko Carstens, Vasily Gorbik, Christian Borntraeger, Alexander Gordeev, Thomas Richter, Sumanth Korikkar, Sebastian Andrzej Siewior, Jiapeng Chong, kernel test robot, linux-s390 Hi Yury, Yury Norov <yury.norov@gmail.com> writes: > cfset_all_start() calls cpumask_weight() to compare the weight of cpumask > with a given number. We can do it more efficiently with > cpumask_weight_{eq, ...} because conditional cpumask_weight may stop > traversing the cpumask earlier, as soon as condition is (or can't be) met. > > Signed-off-by: Yury Norov <yury.norov@gmail.com> > --- > arch/s390/kernel/perf_cpum_cf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c > index ee8707abdb6a..4d217f7f5ccf 100644 > --- a/arch/s390/kernel/perf_cpum_cf.c > +++ b/arch/s390/kernel/perf_cpum_cf.c > @@ -975,7 +975,7 @@ static int cfset_all_start(struct cfset_request *req) > return -ENOMEM; > cpumask_and(mask, &req->mask, cpu_online_mask); > on_each_cpu_mask(mask, cfset_ioctl_on, &p, 1); > - if (atomic_read(&p.cpus_ack) != cpumask_weight(mask)) { > + if (!cpumask_weight_eq(mask, atomic_read(&p.cpus_ack))) { > on_each_cpu_mask(mask, cfset_ioctl_off, &p, 1); > rc = -EIO; > debug_sprintf_event(cf_dbg, 4, "%s CPUs missing", __func__); given that you're adding a bunch of these functions - gt,lt,eq and others, i wonder whether it makes sense to also add cpumask_weight_ne(), so one could just write: if (cpumask_weight_ne(mask, atomic_read(&p.cpus_ack))) { ... } ? /Sven ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 39/49] arch/s390: replace cpumask_weight with cpumask_weight_eq where appropriate 2022-02-11 6:54 ` Sven Schnelle @ 2022-02-11 23:40 ` Yury Norov 0 siblings, 0 replies; 3+ messages in thread From: Yury Norov @ 2022-02-11 23:40 UTC (permalink / raw) To: Sven Schnelle Cc: Andy Shevchenko, Rasmus Villemoes, Andrew Morton, Michał Mirosław, Greg Kroah-Hartman, Peter Zijlstra, David Laight, Joe Perches, Dennis Zhou, Emil Renner Berthing, Nicholas Piggin, Matti Vaittinen, Alexey Klimov, linux-kernel, Heiko Carstens, Vasily Gorbik, Christian Borntraeger, Alexander Gordeev, Thomas Richter, Sumanth Korikkar, Sebastian Andrzej Siewior, Jiapeng Chong, kernel test robot, linux-s390 On Fri, Feb 11, 2022 at 07:54:26AM +0100, Sven Schnelle wrote: > Hi Yury, > > Yury Norov <yury.norov@gmail.com> writes: > > > cfset_all_start() calls cpumask_weight() to compare the weight of cpumask > > with a given number. We can do it more efficiently with > > cpumask_weight_{eq, ...} because conditional cpumask_weight may stop > > traversing the cpumask earlier, as soon as condition is (or can't be) met. > > > > Signed-off-by: Yury Norov <yury.norov@gmail.com> > > --- > > arch/s390/kernel/perf_cpum_cf.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c > > index ee8707abdb6a..4d217f7f5ccf 100644 > > --- a/arch/s390/kernel/perf_cpum_cf.c > > +++ b/arch/s390/kernel/perf_cpum_cf.c > > @@ -975,7 +975,7 @@ static int cfset_all_start(struct cfset_request *req) > > return -ENOMEM; > > cpumask_and(mask, &req->mask, cpu_online_mask); > > on_each_cpu_mask(mask, cfset_ioctl_on, &p, 1); > > - if (atomic_read(&p.cpus_ack) != cpumask_weight(mask)) { > > + if (!cpumask_weight_eq(mask, atomic_read(&p.cpus_ack))) { > > on_each_cpu_mask(mask, cfset_ioctl_off, &p, 1); > > rc = -EIO; > > debug_sprintf_event(cf_dbg, 4, "%s CPUs missing", __func__); > > given that you're adding a bunch of these functions - gt,lt,eq and > others, i wonder whether it makes sense to also add cpumask_weight_ne(), > so one could just write: > > if (cpumask_weight_ne(mask, atomic_read(&p.cpus_ack))) { > ... > } > > ? It will have 3 users in cpumask + 1 in nodemask. I have no strong opinion whether we need it or not. Let's see what people say. Thanks, Yury ^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-02-10 22:49 ` [PATCH 39/49] arch/s390: replace cpumask_weight with cpumask_weight_eq where appropriate Yury Norov
2022-02-11 6:54 ` Sven Schnelle
2022-02-11 23:40 ` Yury Norov
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