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Message-ID: <20250407234032.241215-2-tony.luck@intel.com>
Date: Mon, 7 Apr 2025 16:40:03 -0700
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghuay@...dia.com>,
Reinette Chatre <reinette.chatre@...el.com>,
Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>,
Peter Newman <peternewman@...gle.com>,
James Morse <james.morse@....com>,
Babu Moger <babu.moger@....com>,
Drew Fustini <dfustini@...libre.com>,
Dave Martin <Dave.Martin@....com>,
Anil Keshavamurthy <anil.s.keshavamurthy@...el.com>
Cc: linux-kernel@...r.kernel.org,
patches@...ts.linux.dev,
Tony Luck <tony.luck@...el.com>
Subject: [PATCH v3 01/26] fs/resctrl: Simplify allocation of mon_data structures
Instead of making a special case to allocate and attach these structures
to kernfs files in the default control group, simply allocate a structure
when a new combination of <rid, domain, mevt, do_sum> is needed and
reuse existing structures when possible.
Free all structures when resctrl filesystem is unmounted.
Partial revert of commit fa563b5171e9 ("x86/resctrl: Expand the width
of dom_id by replacing mon_data_bits")
Signed-off-by: Tony Luck <tony.luck@...el.com>
---
fs/resctrl/internal.h | 2 +
fs/resctrl/rdtgroup.c | 138 ++++++++++++------------------------------
2 files changed, 40 insertions(+), 100 deletions(-)
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index ec3863d18f68..e5976bd52a35 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -83,6 +83,7 @@ struct mon_evt {
/**
* struct mon_data - Monitoring details for each event file.
+ * @list: List of all allocated structures.
* @rid: Resource id associated with the event file.
* @evtid: Event id associated with the event file.
* @sum: Set when event must be summed across multiple
@@ -96,6 +97,7 @@ struct mon_evt {
* rdtgroup_mutex.
*/
struct mon_data {
+ struct list_head list;
unsigned int rid;
enum resctrl_event_id evtid;
unsigned int sum;
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 234ec9dbe5b3..338b70c7d302 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -69,6 +69,8 @@ static int rdtgroup_setup_root(struct rdt_fs_context *ctx);
static void rdtgroup_destroy_root(void);
+static void mon_put_kn_priv(void);
+
struct dentry *debugfs_resctrl;
/*
@@ -2873,6 +2875,7 @@ static void rdt_kill_sb(struct super_block *sb)
resctrl_arch_reset_all_ctrls(r);
rmdir_all_sub();
+ mon_put_kn_priv();
rdt_pseudo_lock_release();
rdtgroup_default.mode = RDT_MODE_SHAREABLE;
schemata_list_destroy();
@@ -2895,107 +2898,54 @@ static struct file_system_type rdt_fs_type = {
.kill_sb = rdt_kill_sb,
};
+static LIST_HEAD(kn_priv_list);
+
/**
- * mon_get_default_kn_priv() - Get the mon_data priv data for this event from
- * the default control group.
+ * mon_get_kn_priv() - Get the mon_data priv data for this event
* Called when monitor event files are created for a domain.
- * When called with the default control group, the structure will be allocated.
- * This happens at mount time, before other control or monitor groups are
- * created.
- * This simplifies the lifetime management for rmdir() versus domain-offline
- * as the default control group lives forever, and only one group needs to be
- * special cased.
+ * The same values are used in multiple directories. Keep a list
+ * of allocated structures and reuse an existing one with the same
+ * list of values for rid, domain, etc.
*
- * @r: The resource for the event type being created.
- * @d: The domain for the event type being created.
- * @mevt: The event type being created.
- * @rdtgrp: The rdtgroup for which the monitor file is being created,
- * used to determine if this is the default control group.
- * @do_sum: Whether the SNC sub-numa node monitors are being created.
+ * @rid: The resource for the event type being created.
+ * @domid: The domain for the event type being created.
+ * @mevt: The event type being created.
+ * @do_sum: Whether the SNC sub-numa node monitors are being created.
*/
-static struct mon_data *mon_get_default_kn_priv(struct rdt_resource *r,
- struct rdt_mon_domain *d,
- struct mon_evt *mevt,
- struct rdtgroup *rdtgrp,
- bool do_sum)
+static struct mon_data *mon_get_kn_priv(int rid, int domid, struct mon_evt *mevt, bool do_sum)
{
- struct kernfs_node *kn_dom, *kn_evt;
struct mon_data *priv;
- bool snc_mode;
- char name[32];
- lockdep_assert_held(&rdtgroup_mutex);
-
- snc_mode = r->mon_scope == RESCTRL_L3_NODE;
- if (!do_sum)
- sprintf(name, "mon_%s_%02d", r->name, snc_mode ? d->ci->id : d->hdr.id);
- else
- sprintf(name, "mon_sub_%s_%02d", r->name, d->hdr.id);
-
- kn_dom = kernfs_find_and_get(kn_mondata, name);
- if (!kn_dom)
- return NULL;
-
- kn_evt = kernfs_find_and_get(kn_dom, mevt->name);
-
- /* Is this the creation of the default groups monitor files? */
- if (!kn_evt && rdtgrp == &rdtgroup_default) {
- priv = kzalloc(sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return NULL;
- priv->rid = r->rid;
- priv->domid = do_sum ? d->ci->id : d->hdr.id;
- priv->sum = do_sum;
- priv->evtid = mevt->evtid;
- return priv;
+ list_for_each_entry(priv, &kn_priv_list, list) {
+ if (priv->rid == rid && priv->domid == domid &&
+ priv->sum == do_sum && priv->evtid == mevt->evtid)
+ return priv;
}
- if (!kn_evt)
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
return NULL;
- return kn_evt->priv;
+ priv->rid = rid;
+ priv->domid = domid;
+ priv->sum = do_sum;
+ priv->evtid = mevt->evtid;
+ list_add_tail(&priv->list, &kn_priv_list);
+
+ return priv;
}
/**
- * mon_put_default_kn_priv_all() - Potentially free the mon_data priv data for
- * all events from the default control group.
- * Put the mon_data priv data for all events for a particular domain.
- * When called with the default control group, the priv structure previously
- * allocated will be kfree()d. This should only be done as part of taking a
- * domain offline.
- * Only a domain offline will 'rmdir' monitor files in the default control
- * group. After domain offline releases rdtgrp_mutex, all references will
- * have been removed.
- *
- * @rdtgrp: The rdtgroup for which the monitor files are being removed,
- * used to determine if this is the default control group.
- * @name: The name of the domain or SNC sub-numa domain which is being
- * taken offline.
+ * mon_put_kn_priv() - Free all allocated mon_data structures
+ * Called when resctrl file system is unmounted.
*/
-static void mon_put_default_kn_priv_all(struct rdtgroup *rdtgrp, char *name)
+static void mon_put_kn_priv(void)
{
- struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
- struct kernfs_node *kn_dom, *kn_evt;
- struct mon_evt *mevt;
+ struct mon_data *priv, *tmp;
- lockdep_assert_held(&rdtgroup_mutex);
-
- if (rdtgrp != &rdtgroup_default)
- return;
-
- kn_dom = kernfs_find_and_get(kn_mondata, name);
- if (!kn_dom)
- return;
-
- list_for_each_entry(mevt, &r->evt_list, list) {
- kn_evt = kernfs_find_and_get(kn_dom, mevt->name);
- if (!kn_evt)
- continue;
- if (!kn_evt->priv)
- continue;
-
- kfree(kn_evt->priv);
- kn_evt->priv = NULL;
+ list_for_each_entry_safe(priv, tmp, &kn_priv_list, list) {
+ kfree(priv);
+ list_del(&priv->list);
}
}
@@ -3029,16 +2979,12 @@ static void mon_rmdir_one_subdir(struct rdtgroup *rdtgrp, char *name, char *subn
if (!kn)
return;
- mon_put_default_kn_priv_all(rdtgrp, name);
-
kernfs_put(kn);
- if (kn->dir.subdirs <= 1) {
+ if (kn->dir.subdirs <= 1)
kernfs_remove(kn);
- } else {
- mon_put_default_kn_priv_all(rdtgrp, subname);
+ else
kernfs_remove_by_name(kn, subname);
- }
}
/*
@@ -3081,7 +3027,7 @@ static int mon_add_all_files(struct kernfs_node *kn, struct rdt_mon_domain *d,
return -EPERM;
list_for_each_entry(mevt, &r->evt_list, list) {
- priv = mon_get_default_kn_priv(r, d, mevt, prgrp, do_sum);
+ priv = mon_get_kn_priv(r->rid, do_sum ? d->ci->id : d->hdr.id, mevt, do_sum);
if (WARN_ON_ONCE(!priv))
return -EINVAL;
@@ -3165,17 +3111,9 @@ static void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
struct rdtgroup *prgrp, *crgrp;
struct list_head *head;
- /*
- * During domain-online create the default control group first
- * so that mon_get_default_kn_priv() can find the allocated structure
- * on subsequent calls.
- */
- mkdir_mondata_subdir(kn_mondata, d, r, &rdtgroup_default);
-
list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
parent_kn = prgrp->mon.mon_data_kn;
- if (prgrp != &rdtgroup_default)
- mkdir_mondata_subdir(parent_kn, d, r, prgrp);
+ mkdir_mondata_subdir(parent_kn, d, r, prgrp);
head = &prgrp->mon.crdtgrp_list;
list_for_each_entry(crgrp, head, mon.crdtgrp_list) {
--
2.48.1
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