On Thu, May 16 2024 at 22:04, Costa Shulyupin wrote: > Introduce infrastructure function housekeeping_update() to change > housekeeping_cpumask during runtime and adjust affinities of depended > subsystems. > > Affinity adjustments of subsystems follow in subsequent patches. > > Parent patch: > "sched/isolation: Exclude dynamically isolated CPUs from housekeeping masks" > https://lore.kernel.org/lkml/20240229021414.508972-2-longman@xxxxxxxxxx/ > > Test example for cgroup2: > > cd /sys/fs/cgroup/ > echo +cpuset > cgroup.subtree_control > mkdir test > echo isolated > test/cpuset.cpus.partition > echo $isolate > test/cpuset.cpus This changelog is not telling me anything. Please see Documentation/process/ what changelogs should contain. > +/* > + * housekeeping_update - change housekeeping.cpumasks[type] and propagate the > + * change. > + * > + * Assuming cpuset_mutex is held in sched_partition_write or > + * cpuset_write_resmask. Locking cannot be assumed. lockdep_assert_held() is there to document and enforce such requirements. > + */ > +static int housekeeping_update(enum hk_type type, cpumask_var_t update) Please us 'struct cpumask *update' as it makes it clear what this is about. cpumask_var_t is a hack to make onstack and embedded cpumask and their allocated counterparts possible without #ifdeffery in the code. But any function which is not related to alloc/free of cpumask_var_t should simply use 'struct cpumask *' as argument type. > + housekeeping.flags |= BIT(type); The existing code uses WRITE_ONCE() probably for a reason. Why is that not longer required here? > static int __init housekeeping_setup(char *str, unsigned long flags) > { > cpumask_var_t non_housekeeping_mask, housekeeping_staging; > @@ -314,9 +347,12 @@ int housekeeping_exlude_isolcpus(const struct cpumask *isolcpus, unsigned long f > /* > * Reset housekeeping to bootup default > */ > - for_each_set_bit(type, &housekeeping_boot.flags, HK_TYPE_MAX) > - cpumask_copy(housekeeping.cpumasks[type], > - housekeeping_boot.cpumasks[type]); > + for_each_set_bit(type, &housekeeping_boot.flags, HK_TYPE_MAX) { > + int err = housekeeping_update(type, housekeeping_boot.cpumasks[type]); > + > + if (err) > + return err; > + } > > WRITE_ONCE(housekeeping.flags, housekeeping_boot.flags); > if (!housekeeping_boot.flags && > @@ -344,9 +380,11 @@ int housekeeping_exlude_isolcpus(const struct cpumask *isolcpus, unsigned long f > cpumask_andnot(tmp_mask, src_mask, isolcpus); > if (!cpumask_intersects(tmp_mask, cpu_online_mask)) > return -EINVAL; /* Invalid isolated CPUs */ > - cpumask_copy(housekeeping.cpumasks[type], tmp_mask); > + int err = housekeeping_update(type, tmp_mask); > + > + if (err) > + return err; Do we really need two places to define 'int err' or might it be possible to have one instance defined at function scope? Thanks, tglx
