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authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 01:29:21 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 01:29:21 +0300
commit3e5822e0f99e429fa8b03c956dad890179b5b3b1 (patch)
tree2cfe51abf38e9efe813f20d4c87d41cdfab6de68 /arch
parent59035135b32280fd394ba5765c6f4de24f48353e (diff)
parente0a6ede2dd884adb73a7dde80444185b655f7c79 (diff)
downloadlinux-3e5822e0f99e429fa8b03c956dad890179b5b3b1.tar.xz
Merge tag 'x86_cache_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 resource control updates from Borislav Petkov: - Implement a rename operation in resctrlfs to facilitate handling of application containers with dynamically changing task lists - When reading the tasks file, show the tasks' pid which are only in the current namespace as opposed to showing the pids from the init namespace too - Other fixes and improvements * tag 'x86_cache_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation/x86: Documentation for MON group move feature x86/resctrl: Implement rename op for mon groups x86/resctrl: Factor rdtgroup lock for multi-file ops x86/resctrl: Only show tasks' pid in current pid namespace
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/resctrl/rdtgroup.c171
1 files changed, 156 insertions, 15 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 6ad33f355861..725344048f85 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -726,11 +726,15 @@ unlock:
static void show_rdt_tasks(struct rdtgroup *r, struct seq_file *s)
{
struct task_struct *p, *t;
+ pid_t pid;
rcu_read_lock();
for_each_process_thread(p, t) {
- if (is_closid_match(t, r) || is_rmid_match(t, r))
- seq_printf(s, "%d\n", t->pid);
+ if (is_closid_match(t, r) || is_rmid_match(t, r)) {
+ pid = task_pid_vnr(t);
+ if (pid)
+ seq_printf(s, "%d\n", pid);
+ }
}
rcu_read_unlock();
}
@@ -2301,6 +2305,26 @@ static struct rdtgroup *kernfs_to_rdtgroup(struct kernfs_node *kn)
}
}
+static void rdtgroup_kn_get(struct rdtgroup *rdtgrp, struct kernfs_node *kn)
+{
+ atomic_inc(&rdtgrp->waitcount);
+ kernfs_break_active_protection(kn);
+}
+
+static void rdtgroup_kn_put(struct rdtgroup *rdtgrp, struct kernfs_node *kn)
+{
+ if (atomic_dec_and_test(&rdtgrp->waitcount) &&
+ (rdtgrp->flags & RDT_DELETED)) {
+ if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
+ rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)
+ rdtgroup_pseudo_lock_remove(rdtgrp);
+ kernfs_unbreak_active_protection(kn);
+ rdtgroup_remove(rdtgrp);
+ } else {
+ kernfs_unbreak_active_protection(kn);
+ }
+}
+
struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_node *kn)
{
struct rdtgroup *rdtgrp = kernfs_to_rdtgroup(kn);
@@ -2308,8 +2332,7 @@ struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_node *kn)
if (!rdtgrp)
return NULL;
- atomic_inc(&rdtgrp->waitcount);
- kernfs_break_active_protection(kn);
+ rdtgroup_kn_get(rdtgrp, kn);
mutex_lock(&rdtgroup_mutex);
@@ -2328,17 +2351,7 @@ void rdtgroup_kn_unlock(struct kernfs_node *kn)
return;
mutex_unlock(&rdtgroup_mutex);
-
- if (atomic_dec_and_test(&rdtgrp->waitcount) &&
- (rdtgrp->flags & RDT_DELETED)) {
- if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||
- rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)
- rdtgroup_pseudo_lock_remove(rdtgrp);
- kernfs_unbreak_active_protection(kn);
- rdtgroup_remove(rdtgrp);
- } else {
- kernfs_unbreak_active_protection(kn);
- }
+ rdtgroup_kn_put(rdtgrp, kn);
}
static int mkdir_mondata_all(struct kernfs_node *parent_kn,
@@ -3505,6 +3518,133 @@ out:
return ret;
}
+/**
+ * mongrp_reparent() - replace parent CTRL_MON group of a MON group
+ * @rdtgrp: the MON group whose parent should be replaced
+ * @new_prdtgrp: replacement parent CTRL_MON group for @rdtgrp
+ * @cpus: cpumask provided by the caller for use during this call
+ *
+ * Replaces the parent CTRL_MON group for a MON group, resulting in all member
+ * tasks' CLOSID immediately changing to that of the new parent group.
+ * Monitoring data for the group is unaffected by this operation.
+ */
+static void mongrp_reparent(struct rdtgroup *rdtgrp,
+ struct rdtgroup *new_prdtgrp,
+ cpumask_var_t cpus)
+{
+ struct rdtgroup *prdtgrp = rdtgrp->mon.parent;
+
+ WARN_ON(rdtgrp->type != RDTMON_GROUP);
+ WARN_ON(new_prdtgrp->type != RDTCTRL_GROUP);
+
+ /* Nothing to do when simply renaming a MON group. */
+ if (prdtgrp == new_prdtgrp)
+ return;
+
+ WARN_ON(list_empty(&prdtgrp->mon.crdtgrp_list));
+ list_move_tail(&rdtgrp->mon.crdtgrp_list,
+ &new_prdtgrp->mon.crdtgrp_list);
+
+ rdtgrp->mon.parent = new_prdtgrp;
+ rdtgrp->closid = new_prdtgrp->closid;
+
+ /* Propagate updated closid to all tasks in this group. */
+ rdt_move_group_tasks(rdtgrp, rdtgrp, cpus);
+
+ update_closid_rmid(cpus, NULL);
+}
+
+static int rdtgroup_rename(struct kernfs_node *kn,
+ struct kernfs_node *new_parent, const char *new_name)
+{
+ struct rdtgroup *new_prdtgrp;
+ struct rdtgroup *rdtgrp;
+ cpumask_var_t tmpmask;
+ int ret;
+
+ rdtgrp = kernfs_to_rdtgroup(kn);
+ new_prdtgrp = kernfs_to_rdtgroup(new_parent);
+ if (!rdtgrp || !new_prdtgrp)
+ return -ENOENT;
+
+ /* Release both kernfs active_refs before obtaining rdtgroup mutex. */
+ rdtgroup_kn_get(rdtgrp, kn);
+ rdtgroup_kn_get(new_prdtgrp, new_parent);
+
+ mutex_lock(&rdtgroup_mutex);
+
+ rdt_last_cmd_clear();
+
+ /*
+ * Don't allow kernfs_to_rdtgroup() to return a parent rdtgroup if
+ * either kernfs_node is a file.
+ */
+ if (kernfs_type(kn) != KERNFS_DIR ||
+ kernfs_type(new_parent) != KERNFS_DIR) {
+ rdt_last_cmd_puts("Source and destination must be directories");
+ ret = -EPERM;
+ goto out;
+ }
+
+ if ((rdtgrp->flags & RDT_DELETED) || (new_prdtgrp->flags & RDT_DELETED)) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ if (rdtgrp->type != RDTMON_GROUP || !kn->parent ||
+ !is_mon_groups(kn->parent, kn->name)) {
+ rdt_last_cmd_puts("Source must be a MON group\n");
+ ret = -EPERM;
+ goto out;
+ }
+
+ if (!is_mon_groups(new_parent, new_name)) {
+ rdt_last_cmd_puts("Destination must be a mon_groups subdirectory\n");
+ ret = -EPERM;
+ goto out;
+ }
+
+ /*
+ * If the MON group is monitoring CPUs, the CPUs must be assigned to the
+ * current parent CTRL_MON group and therefore cannot be assigned to
+ * the new parent, making the move illegal.
+ */
+ if (!cpumask_empty(&rdtgrp->cpu_mask) &&
+ rdtgrp->mon.parent != new_prdtgrp) {
+ rdt_last_cmd_puts("Cannot move a MON group that monitors CPUs\n");
+ ret = -EPERM;
+ goto out;
+ }
+
+ /*
+ * Allocate the cpumask for use in mongrp_reparent() to avoid the
+ * possibility of failing to allocate it after kernfs_rename() has
+ * succeeded.
+ */
+ if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL)) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * Perform all input validation and allocations needed to ensure
+ * mongrp_reparent() will succeed before calling kernfs_rename(),
+ * otherwise it would be necessary to revert this call if
+ * mongrp_reparent() failed.
+ */
+ ret = kernfs_rename(kn, new_parent, new_name);
+ if (!ret)
+ mongrp_reparent(rdtgrp, new_prdtgrp, tmpmask);
+
+ free_cpumask_var(tmpmask);
+
+out:
+ mutex_unlock(&rdtgroup_mutex);
+ rdtgroup_kn_put(rdtgrp, kn);
+ rdtgroup_kn_put(new_prdtgrp, new_parent);
+ return ret;
+}
+
static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root *kf)
{
if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
@@ -3522,6 +3662,7 @@ static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root *kf)
static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {
.mkdir = rdtgroup_mkdir,
.rmdir = rdtgroup_rmdir,
+ .rename = rdtgroup_rename,
.show_options = rdtgroup_show_options,
};