linux-kernel - [PATCH v2 08/28] sched: Add cond_resched

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210202185734.1680553-9-bgardon@google.com>
Date:   Tue,  2 Feb 2021 10:57:14 -0800
From:   Ben Gardon <bgardon@...gle.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>, Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Peter Shier <pshier@...gle.com>,
        Peter Feiner <pfeiner@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Yulei Zhang <yulei.kernel@...il.com>,
        Wanpeng Li <kernellwp@...il.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Xiao Guangrong <xiaoguangrong.eric@...il.com>,
        Ben Gardon <bgardon@...gle.com>,
        Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Davidlohr Bueso <dbueso@...e.de>,
        Waiman Long <longman@...hat.com>
Subject: [PATCH v2 08/28] sched: Add cond_resched_rwlock

Safely rescheduling while holding a spin lock is essential for keeping
long running kernel operations running smoothly. Add the facility to
cond_resched rwlocks.

CC: Ingo Molnar <mingo@...hat.com>
CC: Will Deacon <will@...nel.org>
Acked-by: Peter Zijlstra <peterz@...radead.org>
Acked-by: Davidlohr Bueso <dbueso@...e.de>
Acked-by: Waiman Long <longman@...hat.com>
Acked-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Ben Gardon <bgardon@...gle.com>
---
 include/linux/sched.h | 12 ++++++++++++
 kernel/sched/core.c   | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5d1378e5a040..3052d16da3cf 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1883,12 +1883,24 @@ static inline int _cond_resched(void) { return 0; }
 })
 
 extern int __cond_resched_lock(spinlock_t *lock);
+extern int __cond_resched_rwlock_read(rwlock_t *lock);
+extern int __cond_resched_rwlock_write(rwlock_t *lock);
 
 #define cond_resched_lock(lock) ({				\
 	___might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);\
 	__cond_resched_lock(lock);				\
 })
 
+#define cond_resched_rwlock_read(lock) ({			\
+	__might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);	\
+	__cond_resched_rwlock_read(lock);			\
+})
+
+#define cond_resched_rwlock_write(lock) ({			\
+	__might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET);	\
+	__cond_resched_rwlock_write(lock);			\
+})
+
 static inline void cond_resched_rcu(void)
 {
 #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ff74fca39ed2..efed1bf202d1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6709,6 +6709,46 @@ int __cond_resched_lock(spinlock_t *lock)
 }
 EXPORT_SYMBOL(__cond_resched_lock);
 
+int __cond_resched_rwlock_read(rwlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held_read(lock);
+
+	if (rwlock_needbreak(lock) || resched) {
+		read_unlock(lock);
+		if (resched)
+			preempt_schedule_common();
+		else
+			cpu_relax();
+		ret = 1;
+		read_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_rwlock_read);
+
+int __cond_resched_rwlock_write(rwlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held_write(lock);
+
+	if (rwlock_needbreak(lock) || resched) {
+		write_unlock(lock);
+		if (resched)
+			preempt_schedule_common();
+		else
+			cpu_relax();
+		ret = 1;
+		write_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_rwlock_write);
+
 /**
  * yield - yield the current processor to other threads.
  *
-- 
2.30.0.365.g02bc693789-goog