From: Chen Ridong <chenridong@huawei.com>
Refactor acpus_validate_change to handle the special case where
cpuset.cpus can be set even when violating partition sibling CPU
exclusivity rules. This differs from the general validation logic in
validate_change. Add a wrapper function to properly handle this
exceptional case.
Since partition invalidation status can be determined by trialcs->prs_err,
the local variable 'bool invalidate' can be removed.
Signed-off-by: Chen Ridong <chenridong@huawei.com>
---
kernel/cgroup/cpuset.c | 83 +++++++++++++++++++++++-------------------
1 file changed, 45 insertions(+), 38 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 71190f142700..75ad18ab40ae 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2410,43 +2410,11 @@ static bool invalidate_cs_partition(struct cpuset *cs)
return false;
}
-/**
- * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
- * @cs: the cpuset to consider
- * @trialcs: trial cpuset
- * @buf: buffer of cpu numbers written to this cpuset
- */
-static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
- const char *buf)
+static int acpus_validate_change(struct cpuset *cs, struct cpuset *trialcs,
+ struct tmpmasks *tmp)
{
int retval;
- struct tmpmasks tmp;
struct cpuset *parent = parent_cs(cs);
- bool invalidate = false;
- bool force = false;
- int old_prs = cs->partition_root_state;
-
- retval = parse_cpulist(buf, trialcs->cpus_allowed);
- if (retval < 0)
- return retval;
-
- /* Nothing to do if the cpus didn't change */
- if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
- return 0;
-
- if (alloc_tmpmasks(&tmp))
- return -ENOMEM;
-
- compute_trialcs_excpus(trialcs, cs);
-
- invalidate = invalidate_cs_partition(trialcs);
- cs->prs_err = trialcs->prs_err;
-
- /*
- * Check all the descendants in update_cpumasks_hier() if
- * effective_xcpus is to be changed.
- */
- force = !cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus);
retval = validate_change(cs, trialcs);
@@ -2461,7 +2429,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
* partition. However, any conflicting sibling partitions
* have to be marked as invalid too.
*/
- invalidate = true;
+ trialcs->prs_err = PERR_NOTEXCL;
rcu_read_lock();
cpuset_for_each_child(cp, css, parent) {
struct cpumask *xcpus = user_xcpus(trialcs);
@@ -2469,19 +2437,58 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
if (is_partition_valid(cp) &&
cpumask_intersects(xcpus, cp->effective_xcpus)) {
rcu_read_unlock();
- update_parent_effective_cpumask(cp, partcmd_invalidate, NULL, &tmp);
+ update_parent_effective_cpumask(cp, partcmd_invalidate, NULL, tmp);
rcu_read_lock();
}
}
rcu_read_unlock();
retval = 0;
}
+ return retval;
+}
+/**
+ * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
+ * @cs: the cpuset to consider
+ * @trialcs: trial cpuset
+ * @buf: buffer of cpu numbers written to this cpuset
+ */
+static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
+ const char *buf)
+{
+ int retval;
+ struct tmpmasks tmp;
+ bool force = false;
+ int old_prs = cs->partition_root_state;
+
+ retval = parse_cpulist(buf, trialcs->cpus_allowed);
if (retval < 0)
+ return retval;
+
+ /* Nothing to do if the cpus didn't change */
+ if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
+ return 0;
+
+ if (alloc_tmpmasks(&tmp))
+ return -ENOMEM;
+
+ compute_trialcs_excpus(trialcs, cs);
+
+ trialcs->prs_err = PERR_NONE;
+ if (acpus_validate_change(cs, trialcs, &tmp) < 0)
goto out_free;
+ /*
+ * Check all the descendants in update_cpumasks_hier() if
+ * effective_xcpus is to be changed.
+ */
+ force = !cpumask_equal(cs->effective_xcpus, trialcs->effective_xcpus);
+
+ invalidate_cs_partition(trialcs);
+ if (trialcs->prs_err)
+ cs->prs_err = trialcs->prs_err;
if (is_partition_valid(cs) ||
- (is_partition_invalid(cs) && !invalidate)) {
+ (is_partition_invalid(cs) && !trialcs->prs_err)) {
struct cpumask *xcpus = trialcs->effective_xcpus;
if (cpumask_empty(xcpus) && is_partition_invalid(cs))
@@ -2492,7 +2499,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
*/
if (is_remote_partition(cs))
remote_cpus_update(cs, NULL, xcpus, &tmp);
- else if (invalidate)
+ else if (trialcs->prs_err)
update_parent_effective_cpumask(cs, partcmd_invalidate,
NULL, &tmp);
else
--
2.34.1On 8/28/25 8:56 AM, Chen Ridong wrote: > From: Chen Ridong <chenridong@huawei.com> > > Refactor acpus_validate_change to handle the special case where > cpuset.cpus can be set even when violating partition sibling CPU > exclusivity rules. This differs from the general validation logic in > validate_change. Add a wrapper function to properly handle this > exceptional case. > > Since partition invalidation status can be determined by trialcs->prs_err, > the local variable 'bool invalidate' can be removed. > > Signed-off-by: Chen Ridong <chenridong@huawei.com> > --- > kernel/cgroup/cpuset.c | 83 +++++++++++++++++++++++------------------- > 1 file changed, 45 insertions(+), 38 deletions(-) > > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index 71190f142700..75ad18ab40ae 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -2410,43 +2410,11 @@ static bool invalidate_cs_partition(struct cpuset *cs) > return false; > } > > -/** > - * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it > - * @cs: the cpuset to consider > - * @trialcs: trial cpuset > - * @buf: buffer of cpu numbers written to this cpuset > - */ > -static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, > - const char *buf) > +static int acpus_validate_change(struct cpuset *cs, struct cpuset *trialcs, > + struct tmpmasks *tmp) What does "acpu" stand for? I suppose it means cpus_allowed. I will suggest to use a more descriptive name even if it is longer. I did use xcpus for exclusive_cpus, but 'x' is a seldomly used English alphabet that can associate with exclusive_cpus rather easily, but 'a' is not. Cheers, Longman
On 2025/8/30 4:12, Waiman Long wrote: > On 8/28/25 8:56 AM, Chen Ridong wrote: >> From: Chen Ridong <chenridong@huawei.com> >> >> Refactor acpus_validate_change to handle the special case where >> cpuset.cpus can be set even when violating partition sibling CPU >> exclusivity rules. This differs from the general validation logic in >> validate_change. Add a wrapper function to properly handle this >> exceptional case. >> >> Since partition invalidation status can be determined by trialcs->prs_err, >> the local variable 'bool invalidate' can be removed. >> >> Signed-off-by: Chen Ridong <chenridong@huawei.com> >> --- >> kernel/cgroup/cpuset.c | 83 +++++++++++++++++++++++------------------- >> 1 file changed, 45 insertions(+), 38 deletions(-) >> >> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c >> index 71190f142700..75ad18ab40ae 100644 >> --- a/kernel/cgroup/cpuset.c >> +++ b/kernel/cgroup/cpuset.c >> @@ -2410,43 +2410,11 @@ static bool invalidate_cs_partition(struct cpuset *cs) >> return false; >> } >> -/** >> - * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it >> - * @cs: the cpuset to consider >> - * @trialcs: trial cpuset >> - * @buf: buffer of cpu numbers written to this cpuset >> - */ >> -static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, >> - const char *buf) >> +static int acpus_validate_change(struct cpuset *cs, struct cpuset *trialcs, >> + struct tmpmasks *tmp) > > What does "acpu" stand for? I suppose it means cpus_allowed. I will suggest to use a more > descriptive name even if it is longer. I did use xcpus for exclusive_cpus, but 'x' is a seldomly > used English alphabet that can associate with exclusive_cpus rather easily, but 'a' is not. > > Cheers, > Longman > Thanks Longman, The term acpus refers to cpus_allowed. My original naming convention was intended as follows: acpus --> cpus_allowed (allowed cpus) ecpus --> effective_cpus xcpus --> exclusive_cpus excpus --> effective_xcpus -- Best regards, Ridong
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