From 668e041662e92ab3ebcb9eb606d3ec01884546ab Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Sun, 30 Mar 2025 17:52:40 -0400 Subject: cgroup/cpuset: Fix incorrect isolated_cpus update in update_parent_effective_cpumask() Before commit f0af1bfc27b5 ("cgroup/cpuset: Relax constraints to partition & cpus changes"), a cpuset partition cannot be enabled if not all the requested CPUs can be granted from the parent cpuset. After that commit, a cpuset partition can be created even if the requested exclusive CPUs contain CPUs not allowed its parent. The delmask containing exclusive CPUs to be removed from its parent wasn't adjusted accordingly. That is not a problem until the introduction of a new isolated_cpus mask in commit 11e5f407b64a ("cgroup/cpuset: Keep track of CPUs in isolated partitions") as the CPUs in the delmask may be added directly into isolated_cpus. As a result, isolated_cpus may incorrectly contain CPUs that are not isolated leading to incorrect data reporting. Fix this by adjusting the delmask to reflect the actual exclusive CPUs for the creation of the partition. Fixes: 11e5f407b64a ("cgroup/cpuset: Keep track of CPUs in isolated partitions") Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 39c1fc643d77..2c49d80f2a01 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1679,9 +1679,9 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, if (nocpu) return PERR_NOCPUS; - cpumask_copy(tmp->delmask, xcpus); - deleting = true; - subparts_delta++; + deleting = cpumask_and(tmp->delmask, xcpus, parent->effective_xcpus); + if (deleting) + subparts_delta++; new_prs = (cmd == partcmd_enable) ? PRS_ROOT : PRS_ISOLATED; } else if (cmd == partcmd_disable) { /* -- cgit v1.2.3 From 8bf450f3aec3d1bbd725d179502c64b8992588e4 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Sun, 30 Mar 2025 17:52:41 -0400 Subject: cgroup/cpuset: Fix error handling in remote_partition_disable() When remote_partition_disable() is called to disable a remote partition, it always sets the partition to an invalid partition state. It should only do so if an error code (prs_err) has been set. Correct that and add proper error code in places where remote_partition_disable() is called due to error. Fixes: 181c8e091aae ("cgroup/cpuset: Introduce remote partition") Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 2c49d80f2a01..e457b4b1db5d 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1406,6 +1406,7 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, list_add(&cs->remote_sibling, &remote_children); spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); + cs->prs_err = 0; /* * Propagate changes in top_cpuset's effective_cpus down the hierarchy. @@ -1436,9 +1437,11 @@ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp) list_del_init(&cs->remote_sibling); isolcpus_updated = partition_xcpus_del(cs->partition_root_state, NULL, tmp->new_cpus); - cs->partition_root_state = -cs->partition_root_state; - if (!cs->prs_err) - cs->prs_err = PERR_INVCPUS; + if (cs->prs_err) + cs->partition_root_state = -cs->partition_root_state; + else + cs->partition_root_state = PRS_MEMBER; + reset_partition_data(cs); spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); @@ -1471,8 +1474,10 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask, WARN_ON_ONCE(!cpumask_subset(cs->effective_xcpus, subpartitions_cpus)); - if (cpumask_empty(newmask)) + if (cpumask_empty(newmask)) { + cs->prs_err = PERR_CPUSEMPTY; goto invalidate; + } adding = cpumask_andnot(tmp->addmask, newmask, cs->effective_xcpus); deleting = cpumask_andnot(tmp->delmask, cs->effective_xcpus, newmask); @@ -1482,10 +1487,15 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask, * not allocated to other partitions and there are effective_cpus * left in the top cpuset. */ - if (adding && (!capable(CAP_SYS_ADMIN) || - cpumask_intersects(tmp->addmask, subpartitions_cpus) || - cpumask_subset(top_cpuset.effective_cpus, tmp->addmask))) - goto invalidate; + if (adding) { + if (!capable(CAP_SYS_ADMIN)) + cs->prs_err = PERR_ACCESS; + else if (cpumask_intersects(tmp->addmask, subpartitions_cpus) || + cpumask_subset(top_cpuset.effective_cpus, tmp->addmask)) + cs->prs_err = PERR_NOCPUS; + if (cs->prs_err) + goto invalidate; + } spin_lock_irq(&callback_lock); if (adding) @@ -1601,7 +1611,7 @@ static bool prstate_housekeeping_conflict(int prstate, struct cpumask *new_cpus) * The partcmd_update command is used by update_cpumasks_hier() with newmask * NULL and update_cpumask() with newmask set. The partcmd_invalidate is used * by update_cpumask() with NULL newmask. In both cases, the callers won't - * check for error and so partition_root_state and prs_error will be updated + * check for error and so partition_root_state and prs_err will be updated * directly. */ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, @@ -3739,6 +3749,7 @@ retry: if (remote && cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL)) { + cs->prs_err = PERR_HOTPLUG; remote_partition_disable(cs, tmp); compute_effective_cpumask(&new_cpus, cs, parent); remote = false; -- cgit v1.2.3 From f62a5d39368e34a966c8df63e1f05eed7fe9c5de Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Sun, 30 Mar 2025 17:52:42 -0400 Subject: cgroup/cpuset: Remove remote_partition_check() & make update_cpumasks_hier() handle remote partition Currently, changes in exclusive CPUs are being handled in remote_partition_check() by disabling conflicting remote partitions. However, that may lead to results unexpected by the users. Fix this problem by removing remote_partition_check() and making update_cpumasks_hier() handle changes in descendant remote partitions properly. The compute_effective_exclusive_cpumask() function is enhanced to check the exclusive_cpus and effective_xcpus from siblings and excluded them in its effective exclusive CPUs computation and return a value to show if there is any sibling conflicts. This is somewhat like the cpu_exclusive flag check in validate_change(). This is the initial step to enable us to retire the use of cpu_exclusive flag in cgroup v2 in the future. One of the tests in the TEST_MATRIX of the test_cpuset_prs.sh script has to be updated due to changes in the way a child remote partition root is being handled (updated instead of invalidation) in update_cpumasks_hier(). Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 258 ++++++++++++---------- tools/testing/selftests/cgroup/test_cpuset_prs.sh | 4 +- 2 files changed, 143 insertions(+), 119 deletions(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index e457b4b1db5d..0ab63f5974ba 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -86,7 +86,6 @@ static struct list_head remote_children; * A flag to force sched domain rebuild at the end of an operation. * It can be set in * - update_partition_sd_lb() - * - remote_partition_check() * - update_cpumasks_hier() * - cpuset_update_flag() * - cpuset_hotplug_update_tasks() @@ -1340,20 +1339,57 @@ EXPORT_SYMBOL_GPL(cpuset_cpu_is_isolated); * compute_effective_exclusive_cpumask - compute effective exclusive CPUs * @cs: cpuset * @xcpus: effective exclusive CPUs value to be set - * Return: true if xcpus is not empty, false otherwise. + * @real_cs: the real cpuset (can be NULL) + * Return: 0 if there is no sibling conflict, > 0 otherwise * - * Starting with exclusive_cpus (cpus_allowed if exclusive_cpus is not set), - * it must be a subset of parent's effective_xcpus. + * If exclusive_cpus isn't explicitly set or a real_cs is provided, we have to + * scan the sibling cpusets and exclude their exclusive_cpus or effective_xcpus + * as well. The provision of real_cs means that a cpumask is being changed and + * the given cs is a trial one. */ -static bool compute_effective_exclusive_cpumask(struct cpuset *cs, - struct cpumask *xcpus) +static int compute_effective_exclusive_cpumask(struct cpuset *cs, + struct cpumask *xcpus, + struct cpuset *real_cs) { + struct cgroup_subsys_state *css; struct cpuset *parent = parent_cs(cs); + struct cpuset *sibling; + int retval = 0; if (!xcpus) xcpus = cs->effective_xcpus; - return cpumask_and(xcpus, user_xcpus(cs), parent->effective_xcpus); + cpumask_and(xcpus, user_xcpus(cs), parent->effective_xcpus); + + if (!real_cs) { + if (!cpumask_empty(cs->exclusive_cpus)) + return 0; + } else { + cs = real_cs; + } + + /* + * Exclude exclusive CPUs from siblings + */ + rcu_read_lock(); + cpuset_for_each_child(sibling, css, parent) { + if (sibling == cs) + continue; + + if (!cpumask_empty(sibling->exclusive_cpus) && + cpumask_intersects(xcpus, sibling->exclusive_cpus)) { + cpumask_andnot(xcpus, xcpus, sibling->exclusive_cpus); + retval++; + continue; + } + if (!cpumask_empty(sibling->effective_xcpus) && + cpumask_intersects(xcpus, sibling->effective_xcpus)) { + cpumask_andnot(xcpus, xcpus, sibling->effective_xcpus); + retval++; + } + } + rcu_read_unlock(); + return retval; } static inline bool is_remote_partition(struct cpuset *cs) @@ -1395,7 +1431,7 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, * remote partition root underneath it, its exclusive_cpus must * have overlapped with subpartitions_cpus. */ - compute_effective_exclusive_cpumask(cs, tmp->new_cpus); + compute_effective_exclusive_cpumask(cs, tmp->new_cpus, NULL); if (cpumask_empty(tmp->new_cpus) || cpumask_intersects(tmp->new_cpus, subpartitions_cpus) || cpumask_subset(top_cpuset.effective_cpus, tmp->new_cpus)) @@ -1404,8 +1440,10 @@ static int remote_partition_enable(struct cpuset *cs, int new_prs, spin_lock_irq(&callback_lock); isolcpus_updated = partition_xcpus_add(new_prs, NULL, tmp->new_cpus); list_add(&cs->remote_sibling, &remote_children); + cpumask_copy(cs->effective_xcpus, tmp->new_cpus); spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); + cpuset_force_rebuild(); cs->prs_err = 0; /* @@ -1429,22 +1467,24 @@ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp) { bool isolcpus_updated; - compute_effective_exclusive_cpumask(cs, tmp->new_cpus); WARN_ON_ONCE(!is_remote_partition(cs)); - WARN_ON_ONCE(!cpumask_subset(tmp->new_cpus, subpartitions_cpus)); + WARN_ON_ONCE(!cpumask_subset(cs->effective_xcpus, subpartitions_cpus)); spin_lock_irq(&callback_lock); list_del_init(&cs->remote_sibling); isolcpus_updated = partition_xcpus_del(cs->partition_root_state, - NULL, tmp->new_cpus); + NULL, cs->effective_xcpus); if (cs->prs_err) cs->partition_root_state = -cs->partition_root_state; else cs->partition_root_state = PRS_MEMBER; + /* effective_xcpus may need to be changed */ + compute_effective_exclusive_cpumask(cs, NULL, NULL); reset_partition_data(cs); spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); + cpuset_force_rebuild(); /* * Propagate changes in top_cpuset's effective_cpus down the hierarchy. @@ -1456,14 +1496,15 @@ static void remote_partition_disable(struct cpuset *cs, struct tmpmasks *tmp) /* * remote_cpus_update - cpus_exclusive change of remote partition * @cs: the cpuset to be updated - * @newmask: the new effective_xcpus mask + * @xcpus: the new exclusive_cpus mask, if non-NULL + * @excpus: the new effective_xcpus mask * @tmp: temporary masks * * top_cpuset and subpartitions_cpus will be updated or partition can be * invalidated. */ -static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask, - struct tmpmasks *tmp) +static void remote_cpus_update(struct cpuset *cs, struct cpumask *xcpus, + struct cpumask *excpus, struct tmpmasks *tmp) { bool adding, deleting; int prs = cs->partition_root_state; @@ -1474,13 +1515,13 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask, WARN_ON_ONCE(!cpumask_subset(cs->effective_xcpus, subpartitions_cpus)); - if (cpumask_empty(newmask)) { + if (cpumask_empty(excpus)) { cs->prs_err = PERR_CPUSEMPTY; goto invalidate; } - adding = cpumask_andnot(tmp->addmask, newmask, cs->effective_xcpus); - deleting = cpumask_andnot(tmp->delmask, cs->effective_xcpus, newmask); + adding = cpumask_andnot(tmp->addmask, excpus, cs->effective_xcpus); + deleting = cpumask_andnot(tmp->delmask, cs->effective_xcpus, excpus); /* * Additions of remote CPUs is only allowed if those CPUs are @@ -1502,8 +1543,17 @@ static void remote_cpus_update(struct cpuset *cs, struct cpumask *newmask, isolcpus_updated += partition_xcpus_add(prs, NULL, tmp->addmask); if (deleting) isolcpus_updated += partition_xcpus_del(prs, NULL, tmp->delmask); + /* + * Need to update effective_xcpus and exclusive_cpus now as + * update_sibling_cpumasks() below may iterate back to the same cs. + */ + cpumask_copy(cs->effective_xcpus, excpus); + if (xcpus) + cpumask_copy(cs->exclusive_cpus, xcpus); spin_unlock_irq(&callback_lock); update_unbound_workqueue_cpumask(isolcpus_updated); + if (adding || deleting) + cpuset_force_rebuild(); /* * Propagate changes in top_cpuset's effective_cpus down the hierarchy. @@ -1516,47 +1566,6 @@ invalidate: remote_partition_disable(cs, tmp); } -/* - * remote_partition_check - check if a child remote partition needs update - * @cs: the cpuset to be updated - * @newmask: the new effective_xcpus mask - * @delmask: temporary mask for deletion (not in tmp) - * @tmp: temporary masks - * - * This should be called before the given cs has updated its cpus_allowed - * and/or effective_xcpus. - */ -static void remote_partition_check(struct cpuset *cs, struct cpumask *newmask, - struct cpumask *delmask, struct tmpmasks *tmp) -{ - struct cpuset *child, *next; - int disable_cnt = 0; - - /* - * Compute the effective exclusive CPUs that will be deleted. - */ - if (!cpumask_andnot(delmask, cs->effective_xcpus, newmask) || - !cpumask_intersects(delmask, subpartitions_cpus)) - return; /* No deletion of exclusive CPUs in partitions */ - - /* - * Searching the remote children list to look for those that will - * be impacted by the deletion of exclusive CPUs. - * - * Since a cpuset must be removed from the remote children list - * before it can go offline and holding cpuset_mutex will prevent - * any change in cpuset status. RCU read lock isn't needed. - */ - lockdep_assert_held(&cpuset_mutex); - list_for_each_entry_safe(child, next, &remote_children, remote_sibling) - if (cpumask_intersects(child->effective_cpus, delmask)) { - remote_partition_disable(child, tmp); - disable_cnt++; - } - if (disable_cnt) - cpuset_force_rebuild(); -} - /* * prstate_housekeeping_conflict - check for partition & housekeeping conflicts * @prstate: partition root state to be checked @@ -1629,6 +1638,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, bool nocpu; lockdep_assert_held(&cpuset_mutex); + WARN_ON_ONCE(is_remote_partition(cs)); /* * new_prs will only be changed for the partcmd_update and @@ -1670,13 +1680,20 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, nocpu = tasks_nocpu_error(parent, cs, xcpus); if ((cmd == partcmd_enable) || (cmd == partcmd_enablei)) { + /* + * Need to call compute_effective_exclusive_cpumask() in case + * exclusive_cpus not set. Sibling conflict should only happen + * if exclusive_cpus isn't set. + */ + xcpus = tmp->new_cpus; + if (compute_effective_exclusive_cpumask(cs, xcpus, NULL)) + WARN_ON_ONCE(!cpumask_empty(cs->exclusive_cpus)); + /* * Enabling partition root is not allowed if its - * effective_xcpus is empty or doesn't overlap with - * parent's effective_xcpus. + * effective_xcpus is empty. */ - if (cpumask_empty(xcpus) || - !cpumask_intersects(xcpus, parent->effective_xcpus)) + if (cpumask_empty(xcpus)) return PERR_INVCPUS; if (prstate_housekeeping_conflict(new_prs, xcpus)) @@ -1695,13 +1712,16 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, new_prs = (cmd == partcmd_enable) ? PRS_ROOT : PRS_ISOLATED; } else if (cmd == partcmd_disable) { /* - * May need to add cpus to parent's effective_cpus for - * valid partition root. + * May need to add cpus back to parent's effective_cpus + * (and maybe removed from subpartitions_cpus/isolated_cpus) + * for valid partition root. xcpus may contain CPUs that + * shouldn't be removed from the two global cpumasks. */ - adding = !is_prs_invalid(old_prs) && - cpumask_and(tmp->addmask, xcpus, parent->effective_xcpus); - if (adding) + if (is_partition_valid(cs)) { + cpumask_copy(tmp->addmask, cs->effective_xcpus); + adding = true; subparts_delta--; + } new_prs = PRS_MEMBER; } else if (newmask) { /* @@ -1711,6 +1731,7 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, part_error = PERR_CPUSEMPTY; goto write_error; } + /* Check newmask again, whether cpus are available for parent/cs */ nocpu |= tasks_nocpu_error(parent, cs, newmask); @@ -1927,7 +1948,7 @@ static void compute_partition_effective_cpumask(struct cpuset *cs, * 2) All the effective_cpus will be used up and cp * has tasks */ - compute_effective_exclusive_cpumask(cs, new_ecpus); + compute_effective_exclusive_cpumask(cs, new_ecpus, NULL); cpumask_and(new_ecpus, new_ecpus, cpu_active_mask); rcu_read_lock(); @@ -1935,6 +1956,11 @@ static void compute_partition_effective_cpumask(struct cpuset *cs, if (!is_partition_valid(child)) continue; + /* + * There shouldn't be a remote partition underneath another + * partition root. + */ + WARN_ON_ONCE(is_remote_partition(child)); child->prs_err = 0; if (!cpumask_subset(child->effective_xcpus, cs->effective_xcpus)) @@ -1990,32 +2016,39 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, bool remote = is_remote_partition(cp); bool update_parent = false; + old_prs = new_prs = cp->partition_root_state; + /* - * Skip descendent remote partition that acquires CPUs - * directly from top cpuset unless it is cs. + * For child remote partition root (!= cs), we need to call + * remote_cpus_update() if effective_xcpus will be changed. + * Otherwise, we can skip the whole subtree. + * + * remote_cpus_update() will reuse tmp->new_cpus only after + * its value is being processed. */ if (remote && (cp != cs)) { - pos_css = css_rightmost_descendant(pos_css); - continue; - } + compute_effective_exclusive_cpumask(cp, tmp->new_cpus, NULL); + if (cpumask_equal(cp->effective_xcpus, tmp->new_cpus)) { + pos_css = css_rightmost_descendant(pos_css); + continue; + } + rcu_read_unlock(); + remote_cpus_update(cp, NULL, tmp->new_cpus, tmp); + rcu_read_lock(); - /* - * Update effective_xcpus if exclusive_cpus set. - * The case when exclusive_cpus isn't set is handled later. - */ - if (!cpumask_empty(cp->exclusive_cpus) && (cp != cs)) { - spin_lock_irq(&callback_lock); - compute_effective_exclusive_cpumask(cp, NULL); - spin_unlock_irq(&callback_lock); + /* Remote partition may be invalidated */ + new_prs = cp->partition_root_state; + remote = (new_prs == old_prs); } - old_prs = new_prs = cp->partition_root_state; - if (remote || (is_partition_valid(parent) && - is_partition_valid(cp))) + if (remote || (is_partition_valid(parent) && is_partition_valid(cp))) compute_partition_effective_cpumask(cp, tmp->new_cpus); else compute_effective_cpumask(tmp->new_cpus, cp, parent); + if (remote) + goto get_css; /* Ready to update cpuset data */ + /* * A partition with no effective_cpus is allowed as long as * there is no task associated with it. Call @@ -2035,9 +2068,6 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, if (is_in_v2_mode() && !remote && cpumask_empty(tmp->new_cpus)) cpumask_copy(tmp->new_cpus, parent->effective_cpus); - if (remote) - goto get_css; - /* * Skip the whole subtree if * 1) the cpumask remains the same, @@ -2098,6 +2128,9 @@ get_css: spin_lock_irq(&callback_lock); cpumask_copy(cp->effective_cpus, tmp->new_cpus); cp->partition_root_state = new_prs; + if (!cpumask_empty(cp->exclusive_cpus) && (cp != cs)) + compute_effective_exclusive_cpumask(cp, NULL, NULL); + /* * Make sure effective_xcpus is properly set for a valid * partition root. @@ -2184,7 +2217,14 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, parent); if (cpumask_equal(tmp->new_cpus, sibling->effective_cpus)) continue; + } else if (is_remote_partition(sibling)) { + /* + * Change in a sibling cpuset won't affect a remote + * partition root. + */ + continue; } + if (!css_tryget_online(&sibling->css)) continue; @@ -2241,8 +2281,9 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, * trialcs->effective_xcpus is used as a temporary cpumask * for checking validity of the partition root. */ + trialcs->partition_root_state = PRS_MEMBER; if (!cpumask_empty(trialcs->exclusive_cpus) || is_partition_valid(cs)) - compute_effective_exclusive_cpumask(trialcs, NULL); + compute_effective_exclusive_cpumask(trialcs, NULL, cs); } /* Nothing to do if the cpus didn't change */ @@ -2315,19 +2356,13 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, * Call remote_cpus_update() to handle valid remote partition */ if (is_remote_partition(cs)) - remote_cpus_update(cs, xcpus, &tmp); + remote_cpus_update(cs, NULL, xcpus, &tmp); else if (invalidate) update_parent_effective_cpumask(cs, partcmd_invalidate, NULL, &tmp); else update_parent_effective_cpumask(cs, partcmd_update, xcpus, &tmp); - } else if (!cpumask_empty(cs->exclusive_cpus)) { - /* - * Use trialcs->effective_cpus as a temp cpumask - */ - remote_partition_check(cs, trialcs->effective_xcpus, - trialcs->effective_cpus, &tmp); } spin_lock_irq(&callback_lock); @@ -2379,8 +2414,15 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs, if (cpumask_equal(cs->exclusive_cpus, trialcs->exclusive_cpus)) return 0; - if (*buf) - compute_effective_exclusive_cpumask(trialcs, NULL); + if (*buf) { + trialcs->partition_root_state = PRS_MEMBER; + /* + * Reject the change if there is exclusive CPUs conflict with + * the siblings. + */ + if (compute_effective_exclusive_cpumask(trialcs, NULL, cs)) + return -EINVAL; + } /* * Check all the descendants in update_cpumasks_hier() if @@ -2411,8 +2453,8 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs, if (invalidate) remote_partition_disable(cs, &tmp); else - remote_cpus_update(cs, trialcs->effective_xcpus, - &tmp); + remote_cpus_update(cs, trialcs->exclusive_cpus, + trialcs->effective_xcpus, &tmp); } else if (invalidate) { update_parent_effective_cpumask(cs, partcmd_invalidate, NULL, &tmp); @@ -2420,12 +2462,6 @@ static int update_exclusive_cpumask(struct cpuset *cs, struct cpuset *trialcs, update_parent_effective_cpumask(cs, partcmd_update, trialcs->effective_xcpus, &tmp); } - } else if (!cpumask_empty(trialcs->exclusive_cpus)) { - /* - * Use trialcs->effective_cpus as a temp cpumask - */ - remote_partition_check(cs, trialcs->effective_xcpus, - trialcs->effective_cpus, &tmp); } spin_lock_irq(&callback_lock); cpumask_copy(cs->exclusive_cpus, trialcs->exclusive_cpus); @@ -2806,17 +2842,6 @@ static int update_prstate(struct cpuset *cs, int new_prs) if (alloc_cpumasks(NULL, &tmpmask)) return -ENOMEM; - /* - * Setup effective_xcpus if not properly set yet, it will be cleared - * later if partition becomes invalid. - */ - if ((new_prs > 0) && cpumask_empty(cs->exclusive_cpus)) { - spin_lock_irq(&callback_lock); - cpumask_and(cs->effective_xcpus, - cs->cpus_allowed, parent->effective_xcpus); - spin_unlock_irq(&callback_lock); - } - err = update_partition_exclusive(cs, new_prs); if (err) goto out; @@ -3753,7 +3778,6 @@ retry: remote_partition_disable(cs, tmp); compute_effective_cpumask(&new_cpus, cs, parent); remote = false; - cpuset_force_rebuild(); } /* diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh index 400a696a0d21..4e3fabed52da 100755 --- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh +++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh @@ -326,8 +326,8 @@ TEST_MATRIX=( . . X3 P2 . 0 A1:0-2,A2:1-2,XA2:3,XA3:3,A3:3 \ A1:P0,A3:P2 3" " C0-3:X2-3:S+ C1-3:X2-3:S+ C2-3:X2-3:P2 \ - . . X3 . . 0 A1:0-3,A2:1-3,XA2:3,XA3:3,A3:2-3 \ - A1:P0,A3:P-2" + . . X3 . . 0 A1:0-2,A2:1-2,XA2:3,XA3:3,A3:3,XA3:3 \ + A1:P0,A3:P2 3" " C0-3:X2-3:S+ C1-3:X2-3:S+ C2-3:X2-3:P2 \ . X4 . . . 0 A1:0-3,A2:1-3,A3:2-3,XA1:4,XA2:,XA3 \ A1:P0,A3:P-2" -- cgit v1.2.3 From 6da580ec656a5ed135db2cdf574b47635611a4d7 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Sun, 30 Mar 2025 17:52:43 -0400 Subject: cgroup/cpuset: Don't allow creation of local partition over a remote one Currently, we don't allow the creation of a remote partition underneath another local or remote partition. However, it is currently possible to create a new local partition with an existing remote partition underneath it if top_cpuset is the parent. However, the current cpuset code does not set the effective exclusive CPUs correctly to account for those that are taken by the remote partition. Changing the code to properly account for those remote partition CPUs under all possible circumstances can be complex. It is much easier to not allow such a configuration which is not that useful. So forbid that by making sure that exclusive_cpus mask doesn't overlap with subpartitions_cpus and invalidate the partition if that happens. Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset-internal.h | 1 + kernel/cgroup/cpuset.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cpuset-internal.h b/kernel/cgroup/cpuset-internal.h index 976a8bc3ff60..383963e28ac6 100644 --- a/kernel/cgroup/cpuset-internal.h +++ b/kernel/cgroup/cpuset-internal.h @@ -33,6 +33,7 @@ enum prs_errcode { PERR_CPUSEMPTY, PERR_HKEEPING, PERR_ACCESS, + PERR_REMOTE, }; /* bits in struct cpuset flags field */ diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 0ab63f5974ba..d973e0987974 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -61,6 +61,7 @@ static const char * const perr_strings[] = { [PERR_CPUSEMPTY] = "cpuset.cpus and cpuset.cpus.exclusive are empty", [PERR_HKEEPING] = "partition config conflicts with housekeeping setup", [PERR_ACCESS] = "Enable partition not permitted", + [PERR_REMOTE] = "Have remote partition underneath", }; /* @@ -2855,6 +2856,19 @@ static int update_prstate(struct cpuset *cs, int new_prs) goto out; } + /* + * We don't support the creation of a new local partition with + * a remote partition underneath it. This unsupported + * setting can happen only if parent is the top_cpuset because + * a remote partition cannot be created underneath an existing + * local or remote partition. + */ + if ((parent == &top_cpuset) && + cpumask_intersects(cs->exclusive_cpus, subpartitions_cpus)) { + err = PERR_REMOTE; + goto out; + } + /* * If parent is valid partition, enable local partiion. * Otherwise, enable a remote partition. -- cgit v1.2.3 From f0a0bd3d23a44a2c5f628e8ca8ad882498ca5aae Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Sun, 30 Mar 2025 17:52:44 -0400 Subject: cgroup/cpuset: Code cleanup and comment update Rename partition_xcpus_newstate() to isolated_cpus_update(), update_partition_exclusive() to update_partition_exclusive_flag() and the new_xcpus_state variable to isolcpus_updated to make their meanings more explicit. Also add some comments to further clarify the code. No functional change is expected. Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 61 +++++++++++++++++++++++++++++++------------------- 1 file changed, 38 insertions(+), 23 deletions(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index d973e0987974..6a72d7003875 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -65,7 +65,13 @@ static const char * const perr_strings[] = { }; /* - * Exclusive CPUs distributed out to sub-partitions of top_cpuset + * For local partitions, update to subpartitions_cpus & isolated_cpus is done + * in update_parent_effective_cpumask(). For remote partitions, it is done in + * the remote_partition_*() and remote_cpus_update() helpers. + */ +/* + * Exclusive CPUs distributed out to local or remote sub-partitions of + * top_cpuset */ static cpumask_var_t subpartitions_cpus; @@ -1089,9 +1095,14 @@ void cpuset_reset_sched_domains(void) * * Iterate through each task of @cs updating its cpus_allowed to the * effective cpuset's. As this function is called with cpuset_mutex held, - * cpuset membership stays stable. For top_cpuset, task_cpu_possible_mask() - * is used instead of effective_cpus to make sure all offline CPUs are also - * included as hotplug code won't update cpumasks for tasks in top_cpuset. + * cpuset membership stays stable. + * + * For top_cpuset, task_cpu_possible_mask() is used instead of effective_cpus + * to make sure all offline CPUs are also included as hotplug code won't + * update cpumasks for tasks in top_cpuset. + * + * As task_cpu_possible_mask() can be task dependent in arm64, we have to + * do cpu masking per task instead of doing it once for all. */ void cpuset_update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus) { @@ -1151,7 +1162,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, * * Return: 0 if successful, an error code otherwise */ -static int update_partition_exclusive(struct cpuset *cs, int new_prs) +static int update_partition_exclusive_flag(struct cpuset *cs, int new_prs) { bool exclusive = (new_prs > PRS_MEMBER); @@ -1234,12 +1245,12 @@ static void reset_partition_data(struct cpuset *cs) } /* - * partition_xcpus_newstate - Exclusive CPUs state change + * isolated_cpus_update - Update the isolated_cpus mask * @old_prs: old partition_root_state * @new_prs: new partition_root_state * @xcpus: exclusive CPUs with state change */ -static void partition_xcpus_newstate(int old_prs, int new_prs, struct cpumask *xcpus) +static void isolated_cpus_update(int old_prs, int new_prs, struct cpumask *xcpus) { WARN_ON_ONCE(old_prs == new_prs); if (new_prs == PRS_ISOLATED) @@ -1273,8 +1284,8 @@ static bool partition_xcpus_add(int new_prs, struct cpuset *parent, isolcpus_updated = (new_prs != parent->partition_root_state); if (isolcpus_updated) - partition_xcpus_newstate(parent->partition_root_state, new_prs, - xcpus); + isolated_cpus_update(parent->partition_root_state, new_prs, + xcpus); cpumask_andnot(parent->effective_cpus, parent->effective_cpus, xcpus); return isolcpus_updated; @@ -1304,8 +1315,8 @@ static bool partition_xcpus_del(int old_prs, struct cpuset *parent, isolcpus_updated = (old_prs != parent->partition_root_state); if (isolcpus_updated) - partition_xcpus_newstate(old_prs, parent->partition_root_state, - xcpus); + isolated_cpus_update(old_prs, parent->partition_root_state, + xcpus); cpumask_and(xcpus, xcpus, cpu_active_mask); cpumask_or(parent->effective_cpus, parent->effective_cpus, xcpus); @@ -1634,8 +1645,8 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, int old_prs, new_prs; int part_error = PERR_NONE; /* Partition error? */ int subparts_delta = 0; - struct cpumask *xcpus; /* cs effective_xcpus */ int isolcpus_updated = 0; + struct cpumask *xcpus = user_xcpus(cs); bool nocpu; lockdep_assert_held(&cpuset_mutex); @@ -1647,7 +1658,6 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd, */ adding = deleting = false; old_prs = new_prs = cs->partition_root_state; - xcpus = user_xcpus(cs); if (cmd == partcmd_invalidate) { if (is_prs_invalid(old_prs)) @@ -1861,7 +1871,7 @@ write_error: * CPU lists in cs haven't been updated yet. So defer it to later. */ if ((old_prs != new_prs) && (cmd != partcmd_update)) { - int err = update_partition_exclusive(cs, new_prs); + int err = update_partition_exclusive_flag(cs, new_prs); if (err) return err; @@ -1899,7 +1909,7 @@ write_error: update_unbound_workqueue_cpumask(isolcpus_updated); if ((old_prs != new_prs) && (cmd == partcmd_update)) - update_partition_exclusive(cs, new_prs); + update_partition_exclusive_flag(cs, new_prs); if (adding || deleting) { cpuset_update_tasks_cpumask(parent, tmp->addmask); @@ -2829,7 +2839,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) int err = PERR_NONE, old_prs = cs->partition_root_state; struct cpuset *parent = parent_cs(cs); struct tmpmasks tmpmask; - bool new_xcpus_state = false; + bool isolcpus_updated = false; if (old_prs == new_prs) return 0; @@ -2843,7 +2853,7 @@ static int update_prstate(struct cpuset *cs, int new_prs) if (alloc_cpumasks(NULL, &tmpmask)) return -ENOMEM; - err = update_partition_exclusive(cs, new_prs); + err = update_partition_exclusive_flag(cs, new_prs); if (err) goto out; @@ -2884,8 +2894,9 @@ static int update_prstate(struct cpuset *cs, int new_prs) } else if (old_prs && new_prs) { /* * A change in load balance state only, no change in cpumasks. + * Need to update isolated_cpus. */ - new_xcpus_state = true; + isolcpus_updated = true; } else { /* * Switching back to member is always allowed even if it @@ -2909,7 +2920,7 @@ out: */ if (err) { new_prs = -new_prs; - update_partition_exclusive(cs, new_prs); + update_partition_exclusive_flag(cs, new_prs); } spin_lock_irq(&callback_lock); @@ -2917,14 +2928,18 @@ out: WRITE_ONCE(cs->prs_err, err); if (!is_partition_valid(cs)) reset_partition_data(cs); - else if (new_xcpus_state) - partition_xcpus_newstate(old_prs, new_prs, cs->effective_xcpus); + else if (isolcpus_updated) + isolated_cpus_update(old_prs, new_prs, cs->effective_xcpus); spin_unlock_irq(&callback_lock); - update_unbound_workqueue_cpumask(new_xcpus_state); + update_unbound_workqueue_cpumask(isolcpus_updated); - /* Force update if switching back to member */ + /* Force update if switching back to member & update effective_xcpus */ update_cpumasks_hier(cs, &tmpmask, !new_prs); + /* A newly created partition must have effective_xcpus set */ + WARN_ON_ONCE(!old_prs && (new_prs > 0) + && cpumask_empty(cs->effective_xcpus)); + /* Update sched domains and load balance flag */ update_partition_sd_lb(cs, old_prs); -- cgit v1.2.3 From 52e039f9e2557f46b083d5d8ca94793ddea44a07 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Sun, 30 Mar 2025 17:52:45 -0400 Subject: cgroup/cpuset: Remove unneeded goto in sched_partition_write() and rename it The goto statement in sched_partition_write() is not needed. Remove it and rename sched_partition_write()/sched_partition_show() to cpuset_partition_write()/cpuset_partition_show(). Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 6a72d7003875..4921919c8704 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3272,7 +3272,7 @@ int cpuset_common_seq_show(struct seq_file *sf, void *v) return ret; } -static int sched_partition_show(struct seq_file *seq, void *v) +static int cpuset_partition_show(struct seq_file *seq, void *v) { struct cpuset *cs = css_cs(seq_css(seq)); const char *err, *type = NULL; @@ -3303,7 +3303,7 @@ static int sched_partition_show(struct seq_file *seq, void *v) return 0; } -static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf, +static ssize_t cpuset_partition_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct cpuset *cs = css_cs(of_css(of)); @@ -3324,11 +3324,8 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf, css_get(&cs->css); cpus_read_lock(); mutex_lock(&cpuset_mutex); - if (!is_cpuset_online(cs)) - goto out_unlock; - - retval = update_prstate(cs, val); -out_unlock: + if (is_cpuset_online(cs)) + retval = update_prstate(cs, val); mutex_unlock(&cpuset_mutex); cpus_read_unlock(); css_put(&cs->css); @@ -3372,8 +3369,8 @@ static struct cftype dfl_files[] = { { .name = "cpus.partition", - .seq_show = sched_partition_show, - .write = sched_partition_write, + .seq_show = cpuset_partition_show, + .write = cpuset_partition_write, .private = FILE_PARTITION_ROOT, .flags = CFTYPE_NOT_ON_ROOT, .file_offset = offsetof(struct cpuset, partition_file), -- cgit v1.2.3 From 7d6c63c3191427a69ffd1383146df01f695d6195 Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Tue, 1 Apr 2025 10:09:12 -0700 Subject: cgroup: rstat: call cgroup_rstat_updated_list with cgroup_rstat_lock The commit 093c8812de2d ("cgroup: rstat: Cleanup flushing functions and locking") during cleanup accidentally changed the code to call cgroup_rstat_updated_list() without cgroup_rstat_lock which is required. Fix it. Fixes: 093c8812de2d ("cgroup: rstat: Cleanup flushing functions and locking") Reported-by: Jakub Kicinski Reported-by: Breno Leitao Reported-by: Venkat Rao Bagalkote Closes: https://lore.kernel.org/all/6564c3d6-9372-4352-9847-1eb3aea07ca4@linux.ibm.com/ Signed-off-by: Shakeel Butt Signed-off-by: Tejun Heo --- kernel/cgroup/rstat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index 4bb587d5d34f..b2239156b7de 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -318,10 +318,11 @@ __bpf_kfunc void cgroup_rstat_flush(struct cgroup *cgrp) might_sleep(); for_each_possible_cpu(cpu) { - struct cgroup *pos = cgroup_rstat_updated_list(cgrp, cpu); + struct cgroup *pos; /* Reacquire for each CPU to avoid disabling IRQs too long */ __cgroup_rstat_lock(cgrp, cpu); + pos = cgroup_rstat_updated_list(cgrp, cpu); for (; pos; pos = pos->rstat_flush_next) { struct cgroup_subsys_state *css; -- cgit v1.2.3 From a22b3d54de94f82ca057cc2ebf9496fa91ebf698 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Sun, 30 Mar 2025 17:52:39 -0400 Subject: cgroup/cpuset: Fix race between newly created partition and dying one There is a possible race between removing a cgroup diectory that is a partition root and the creation of a new partition. The partition to be removed can be dying but still online, it doesn't not currently participate in checking for exclusive CPUs conflict, but the exclusive CPUs are still there in subpartitions_cpus and isolated_cpus. These two cpumasks are global states that affect the operation of cpuset partitions. The exclusive CPUs in dying cpusets will only be removed when cpuset_css_offline() function is called after an RCU delay. As a result, it is possible that a new partition can be created with exclusive CPUs that overlap with those of a dying one. When that dying partition is finally offlined, it removes those overlapping exclusive CPUs from subpartitions_cpus and maybe isolated_cpus resulting in an incorrect CPU configuration. This bug was found when a warning was triggered in remote_partition_disable() during testing because the subpartitions_cpus mask was empty. One possible way to fix this is to iterate the dying cpusets as well and avoid using the exclusive CPUs in those dying cpusets. However, this can still cause random partition creation failures or other anomalies due to racing. A better way to fix this race is to reset the partition state at the moment when a cpuset is being killed. Introduce a new css_killed() CSS function pointer and call it, if defined, before setting CSS_DYING flag in kill_css(). Also update the css_is_dying() helper to use the CSS_DYING flag introduced by commit 33c35aa48178 ("cgroup: Prevent kill_css() from being called more than once") for proper synchronization. Add a new cpuset_css_killed() function to reset the partition state of a valid partition root if it is being killed. Fixes: ee8dde0cd2ce ("cpuset: Add new v2 cpuset.sched.partition flag") Signed-off-by: Waiman Long Signed-off-by: Tejun Heo --- include/linux/cgroup-defs.h | 1 + include/linux/cgroup.h | 2 +- kernel/cgroup/cgroup.c | 6 ++++++ kernel/cgroup/cpuset.c | 20 +++++++++++++++++--- 4 files changed, 25 insertions(+), 4 deletions(-) (limited to 'kernel/cgroup') diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 485b651869d9..5bc8f55c8cca 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -710,6 +710,7 @@ struct cgroup_subsys { void (*css_released)(struct cgroup_subsys_state *css); void (*css_free)(struct cgroup_subsys_state *css); void (*css_reset)(struct cgroup_subsys_state *css); + void (*css_killed)(struct cgroup_subsys_state *css); void (*css_rstat_flush)(struct cgroup_subsys_state *css, int cpu); int (*css_extra_stat_show)(struct seq_file *seq, struct cgroup_subsys_state *css); diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 28e999f2c642..e7da3c3b098b 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -344,7 +344,7 @@ static inline u64 cgroup_id(const struct cgroup *cgrp) */ static inline bool css_is_dying(struct cgroup_subsys_state *css) { - return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt); + return css->flags & CSS_DYING; } static inline void cgroup_get(struct cgroup *cgrp) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index f231fe3a0744..49d622205997 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -5909,6 +5909,12 @@ static void kill_css(struct cgroup_subsys_state *css) if (css->flags & CSS_DYING) return; + /* + * Call css_killed(), if defined, before setting the CSS_DYING flag + */ + if (css->ss->css_killed) + css->ss->css_killed(css); + css->flags |= CSS_DYING; /* diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 4921919c8704..306b60430091 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3536,9 +3536,6 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css) cpus_read_lock(); mutex_lock(&cpuset_mutex); - if (is_partition_valid(cs)) - update_prstate(cs, 0); - if (!cpuset_v2() && is_sched_load_balance(cs)) cpuset_update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); @@ -3549,6 +3546,22 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css) cpus_read_unlock(); } +static void cpuset_css_killed(struct cgroup_subsys_state *css) +{ + struct cpuset *cs = css_cs(css); + + cpus_read_lock(); + mutex_lock(&cpuset_mutex); + + /* Reset valid partition back to member */ + if (is_partition_valid(cs)) + update_prstate(cs, PRS_MEMBER); + + mutex_unlock(&cpuset_mutex); + cpus_read_unlock(); + +} + static void cpuset_css_free(struct cgroup_subsys_state *css) { struct cpuset *cs = css_cs(css); @@ -3670,6 +3683,7 @@ struct cgroup_subsys cpuset_cgrp_subsys = { .css_alloc = cpuset_css_alloc, .css_online = cpuset_css_online, .css_offline = cpuset_css_offline, + .css_killed = cpuset_css_killed, .css_free = cpuset_css_free, .can_attach = cpuset_can_attach, .cancel_attach = cpuset_cancel_attach, -- cgit v1.2.3 From 87c259a7a359e73e6c52c68fcbec79988999b4e6 Mon Sep 17 00:00:00 2001 From: gaoxu Date: Thu, 17 Apr 2025 07:30:00 +0000 Subject: cgroup: Fix compilation issue due to cgroup_mutex not being exported MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When adding folio_memcg function call in the zram module for Android16-6.12, the following error occurs during compilation: ERROR: modpost: "cgroup_mutex" [../soc-repo/zram.ko] undefined! This error is caused by the indirect call to lockdep_is_held(&cgroup_mutex) within folio_memcg. The export setting for cgroup_mutex is controlled by the CONFIG_PROVE_RCU macro. If CONFIG_LOCKDEP is enabled while CONFIG_PROVE_RCU is not, this compilation error will occur. To resolve this issue, add a parallel macro CONFIG_LOCKDEP control to ensure cgroup_mutex is properly exported when needed. Signed-off-by: gao xu Acked-by: Michal Koutný Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 3caf2cd86e65..9c1bf7f7c812 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -90,7 +90,7 @@ DEFINE_MUTEX(cgroup_mutex); DEFINE_SPINLOCK(css_set_lock); -#ifdef CONFIG_PROVE_RCU +#if (defined CONFIG_PROVE_RCU || defined CONFIG_LOCKDEP) EXPORT_SYMBOL_GPL(cgroup_mutex); EXPORT_SYMBOL_GPL(css_set_lock); #endif -- cgit v1.2.3 From 1bf67c8fdbda21fadd564a12dbe2b13c1ea5eda7 Mon Sep 17 00:00:00 2001 From: "T.J. Mercier" Date: Wed, 16 Apr 2025 21:17:51 +0000 Subject: cgroup/cpuset-v1: Add missing support for cpuset_v2_mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Android has mounted the v1 cpuset controller using filesystem type "cpuset" (not "cgroup") since 2015 [1], and depends on the resulting behavior where the controller name is not added as a prefix for cgroupfs files. [2] Later, a problem was discovered where cpu hotplug onlining did not affect the cpuset/cpus files, which Android carried an out-of-tree patch to address for a while. An attempt was made to upstream this patch, but the recommendation was to use the "cpuset_v2_mode" mount option instead. [3] An effort was made to do so, but this fails with "cgroup: Unknown parameter 'cpuset_v2_mode'" because commit e1cba4b85daa ("cgroup: Add mount flag to enable cpuset to use v2 behavior in v1 cgroup") did not update the special cased cpuset_mount(), and only the cgroup (v1) filesystem type was updated. Add parameter parsing to the cpuset filesystem type so that cpuset_v2_mode works like the cgroup filesystem type: $ mkdir /dev/cpuset $ mount -t cpuset -ocpuset_v2_mode none /dev/cpuset $ mount|grep cpuset none on /dev/cpuset type cgroup (rw,relatime,cpuset,noprefix,cpuset_v2_mode,release_agent=/sbin/cpuset_release_agent) [1] https://cs.android.com/android/_/android/platform/system/core/+/b769c8d24fd7be96f8968aa4c80b669525b930d3 [2] https://cs.android.com/android/platform/superproject/main/+/main:system/core/libprocessgroup/setup/cgroup_map_write.cpp;drc=2dac5d89a0f024a2d0cc46a80ba4ee13472f1681;l=192 [3] https://lore.kernel.org/lkml/f795f8be-a184-408a-0b5a-553d26061385@redhat.com/T/ Fixes: e1cba4b85daa ("cgroup: Add mount flag to enable cpuset to use v2 behavior in v1 cgroup") Signed-off-by: T.J. Mercier Acked-by: Waiman Long Reviewed-by: Kamalesh Babulal Acked-by: Michal Koutný Signed-off-by: Tejun Heo --- kernel/cgroup/cgroup.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 9c1bf7f7c812..63e5b90da1f3 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2353,9 +2353,37 @@ static struct file_system_type cgroup2_fs_type = { }; #ifdef CONFIG_CPUSETS_V1 +enum cpuset_param { + Opt_cpuset_v2_mode, +}; + +static const struct fs_parameter_spec cpuset_fs_parameters[] = { + fsparam_flag ("cpuset_v2_mode", Opt_cpuset_v2_mode), + {} +}; + +static int cpuset_parse_param(struct fs_context *fc, struct fs_parameter *param) +{ + struct cgroup_fs_context *ctx = cgroup_fc2context(fc); + struct fs_parse_result result; + int opt; + + opt = fs_parse(fc, cpuset_fs_parameters, param, &result); + if (opt < 0) + return opt; + + switch (opt) { + case Opt_cpuset_v2_mode: + ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE; + return 0; + } + return -EINVAL; +} + static const struct fs_context_operations cpuset_fs_context_ops = { .get_tree = cgroup1_get_tree, .free = cgroup_fs_context_free, + .parse_param = cpuset_parse_param, }; /* @@ -2392,6 +2420,7 @@ static int cpuset_init_fs_context(struct fs_context *fc) static struct file_system_type cpuset_fs_type = { .name = "cpuset", .init_fs_context = cpuset_init_fs_context, + .parameters = cpuset_fs_parameters, .fs_flags = FS_USERNS_MOUNT, }; #endif -- cgit v1.2.3