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Message-ID: <20221129120149.1035444-2-peternewman@google.com>
Date: Tue, 29 Nov 2022 13:01:48 +0100
From: Peter Newman <peternewman@...gle.com>
To: fenghua.yu@...el.com, reinette.chatre@...el.com
Cc: Babu.Moger@....com, bp@...en8.de, dave.hansen@...ux.intel.com,
eranian@...gle.com, gupasani@...gle.com, hpa@...or.com,
james.morse@....com, linux-kernel@...r.kernel.org,
mingo@...hat.com, tglx@...utronix.de, x86@...nel.org,
Peter Newman <peternewman@...gle.com>
Subject: [PATCH v2 1/2] x86/resctrl: Factor rdtgroup lock for multi-file ops
rdtgroup_kn_lock_live() can only release a kernfs lock for a single file
before waiting on the rdtgroup_mutex, limiting its usefulness for
operations on multiple files, such as rename.
Factor the work needed to respectively break and unbreak active
protection on an individual file into rdtgroup_kn_{get,put}().
This refactoring should not result in any functional change.
Signed-off-by: Peter Newman <peternewman@...gle.com>
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 35 ++++++++++++++++----------
1 file changed, 22 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index e5a48f05e787..03b51543c26d 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2026,6 +2026,26 @@ 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);
@@ -2033,8 +2053,7 @@ 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);
@@ -2053,17 +2072,7 @@ 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,
--
2.38.1.584.g0f3c55d4c2-goog
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