* [PATCH v2] sched: sched_domain fix highest_flag_domain function @ 2020-10-27 3:32 Xuewen Yan 2020-10-27 9:57 ` Dietmar Eggemann 0 siblings, 1 reply; 3+ messages in thread From: Xuewen Yan @ 2020-10-27 3:32 UTC (permalink / raw) To: xuewen.yan, mingo, peterz, juri.lelli, vincent.guittot Cc: dietmar.eggemann, rostedt, bsegall, mgorman, linux-kernel, Xuewen Yan the highest_flag_domain is to search the highest sched_domain containing flag, but if the lower sched_domain didn't contain the flag, but the higher sched_domain contains the flag, the function will return NULL instead of the higher sched_domain. For example: In MC domain : no SD_ASYM_CPUCAPACITY flag; In DIE domain : containing SD_ASYM_CPUCAPACITY flag; the "highest_flag_domain(cpu, SD_ASYM_CPUCAPACITY)" will return NULL. Signed-off-by: Xuewen Yan <xuewen.yan94@gmail.com> --- kernel/sched/sched.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 28709f6..2c7c566 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1427,7 +1427,7 @@ static inline struct sched_domain *highest_flag_domain(int cpu, int flag) for_each_domain(cpu, sd) { if (!(sd->flags & flag)) - break; + continue; hsd = sd; } -- 1.9.1 ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] sched: sched_domain fix highest_flag_domain function 2020-10-27 3:32 [PATCH v2] sched: sched_domain fix highest_flag_domain function Xuewen Yan @ 2020-10-27 9:57 ` Dietmar Eggemann 2020-10-27 10:47 ` Valentin Schneider 0 siblings, 1 reply; 3+ messages in thread From: Dietmar Eggemann @ 2020-10-27 9:57 UTC (permalink / raw) To: Xuewen Yan, xuewen.yan, mingo, peterz, juri.lelli, vincent.guittot Cc: rostedt, bsegall, mgorman, linux-kernel On 27/10/2020 04:32, Xuewen Yan wrote: > the highest_flag_domain is to search the highest sched_domain > containing flag, but if the lower sched_domain didn't contain > the flag, but the higher sched_domain contains the flag, the > function will return NULL instead of the higher sched_domain. > > For example: > In MC domain : no SD_ASYM_CPUCAPACITY flag; > In DIE domain : containing SD_ASYM_CPUCAPACITY flag; > the "highest_flag_domain(cpu, SD_ASYM_CPUCAPACITY)" will return NULL. > > Signed-off-by: Xuewen Yan <xuewen.yan94@gmail.com> > --- > kernel/sched/sched.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index 28709f6..2c7c566 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -1427,7 +1427,7 @@ static inline struct sched_domain *highest_flag_domain(int cpu, int flag) > > for_each_domain(cpu, sd) { > if (!(sd->flags & flag)) > - break; > + continue; > hsd = sd; > } We distinguish between SDF_SHARED_PARENT and SDF_SHARED_CHILD SD flags. 1 SD_FLAG(*SD_ASYM_CPUCAPACITY*, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) 2 SD_FLAG(SD_SERIALIZE, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) 3 SD_FLAG(SD_OVERLAP, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) 4 SD_FLAG(SD_NUMA, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) 1 SD_FLAG(SD_BALANCE_NEWIDLE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 2 SD_FLAG(SD_BALANCE_EXEC, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 3 SD_FLAG(SD_BALANCE_FORK, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 4 SD_FLAG(SD_BALANCE_WAKE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 5 82 SD_FLAG(SD_WAKE_AFFINE, SDF_SHARED_CHILD) 6 SD_FLAG(SD_SHARE_CPUCAPACITY, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 7 SD_FLAG(SD_SHARE_PKG_RESOURCES, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 8 SD_FLAG(SD_ASYM_PACKING, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) We call lowest_flag_domain() on SDF_SHARED_PARENT and highest_flag_domain() on SDF_SHARED_CHILD SD flags. 1 sd = lowest_flag_domain(cpu, SD_NUMA); 2 sd = lowest_flag_domain(cpu, *SD_ASYM_CPUCAPACITY*); 1 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 2 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] sched: sched_domain fix highest_flag_domain function 2020-10-27 9:57 ` Dietmar Eggemann @ 2020-10-27 10:47 ` Valentin Schneider 0 siblings, 0 replies; 3+ messages in thread From: Valentin Schneider @ 2020-10-27 10:47 UTC (permalink / raw) To: Dietmar Eggemann Cc: Xuewen Yan, xuewen.yan, mingo, peterz, juri.lelli, vincent.guittot, rostedt, bsegall, mgorman, linux-kernel On 27/10/20 09:57, Dietmar Eggemann wrote: > On 27/10/2020 04:32, Xuewen Yan wrote: >> the highest_flag_domain is to search the highest sched_domain >> containing flag, but if the lower sched_domain didn't contain >> the flag, but the higher sched_domain contains the flag, the >> function will return NULL instead of the higher sched_domain. >> >> For example: >> In MC domain : no SD_ASYM_CPUCAPACITY flag; >> In DIE domain : containing SD_ASYM_CPUCAPACITY flag; >> the "highest_flag_domain(cpu, SD_ASYM_CPUCAPACITY)" will return NULL. >> >> Signed-off-by: Xuewen Yan <xuewen.yan94@gmail.com> >> --- >> kernel/sched/sched.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h >> index 28709f6..2c7c566 100644 >> --- a/kernel/sched/sched.h >> +++ b/kernel/sched/sched.h >> @@ -1427,7 +1427,7 @@ static inline struct sched_domain *highest_flag_domain(int cpu, int flag) >> >> for_each_domain(cpu, sd) { >> if (!(sd->flags & flag)) >> - break; >> + continue; >> hsd = sd; >> } > > We distinguish between SDF_SHARED_PARENT and SDF_SHARED_CHILD SD flags. > > 1 SD_FLAG(*SD_ASYM_CPUCAPACITY*, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) > 2 SD_FLAG(SD_SERIALIZE, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) > 3 SD_FLAG(SD_OVERLAP, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) > 4 SD_FLAG(SD_NUMA, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) > > 1 SD_FLAG(SD_BALANCE_NEWIDLE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) > 2 SD_FLAG(SD_BALANCE_EXEC, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) > 3 SD_FLAG(SD_BALANCE_FORK, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) > 4 SD_FLAG(SD_BALANCE_WAKE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) > 5 82 SD_FLAG(SD_WAKE_AFFINE, SDF_SHARED_CHILD) > 6 SD_FLAG(SD_SHARE_CPUCAPACITY, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) > 7 SD_FLAG(SD_SHARE_PKG_RESOURCES, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) > 8 SD_FLAG(SD_ASYM_PACKING, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) > > We call lowest_flag_domain() on SDF_SHARED_PARENT and > highest_flag_domain() on SDF_SHARED_CHILD SD flags. > > 1 sd = lowest_flag_domain(cpu, SD_NUMA); > 2 sd = lowest_flag_domain(cpu, *SD_ASYM_CPUCAPACITY*); > > 1 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); > 2 sd = highest_flag_domain(cpu, SD_ASYM_PACKING); Spot on! In some of my earliest instrumentation patches I had a SCHED_WARN_ON() for when highest_flag_domain() is passed an SDF_SHARED_PARENT flag (for some reason I don't have the equivalent for lowest_flag_domain() in that branch). I had ditched that as it didn't seem that useful, but perhaps that wasn't so accurate :) ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-10-27 10:47 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-10-27 3:32 [PATCH v2] sched: sched_domain fix highest_flag_domain function Xuewen Yan 2020-10-27 9:57 ` Dietmar Eggemann 2020-10-27 10:47 ` Valentin Schneider
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