From: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
virtualization@lists.linux-foundation.org,
linux-s390@vger.kernel.org,
xen-devel-request@lists.xenproject.org, kvm@vger.kernel.org
Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
mingo@redhat.com, peterz@infradead.org,
paulmck@linux.vnet.ibm.com, will.deacon@arm.com,
kernellwp@gmail.com, jgross@suse.com, pbonzini@redhat.com,
bsingharora@gmail.com, Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Subject: [PATCH v3 1/4] kernel/sched: introduce vcpu preempted check interface
Date: Thu, 21 Jul 2016 07:45:11 -0400 [thread overview]
Message-ID: <1469101514-49475-2-git-send-email-xinhui.pan@linux.vnet.ibm.com> (raw)
In-Reply-To: <1469101514-49475-1-git-send-email-xinhui.pan@linux.vnet.ibm.com>
This patch supports to fix lock holder preemption issue.
For kernel users, we could use bool vcpu_is_preempted(int cpu) to detech if
one vcpu is preempted or not.
The default implementation is a macro defined by false. So compiler can
wrap it out if arch dose not support such vcpu pteempted check.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
---
include/linux/sched.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6e42ada..cbe0574 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -3293,6 +3293,18 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
#endif /* CONFIG_SMP */
+/*
+ * In order to deal with a various lock holder preemption issues provide an
+ * interface to see if a vCPU is currently running or not.
+ *
+ * This allows us to terminate optimistic spin loops and block, analogous to
+ * the native optimistic spin heuristic of testing if the lock owner task is
+ * running or not.
+ */
+#ifndef vcpu_is_preempted
+#define vcpu_is_preempted(cpu) false
+#endif
+
extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
--
2.4.11
next prev parent reply other threads:[~2016-07-21 7:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-21 11:45 [PATCH v3 0/4] implement vcpu preempted check Pan Xinhui
2016-07-21 11:45 ` Pan Xinhui [this message]
2016-07-21 11:45 ` [PATCH v3 2/4] powerpc/spinlock: support " Pan Xinhui
2016-07-21 11:45 ` [PATCH v3 3/4] locking/osq: Drop the overhead of osq_lock() Pan Xinhui
2016-07-21 11:45 ` [PATCH v3 4/4] kernel/locking: Drop the overhead of {mutex, rwsem}_spin_on_owner Pan Xinhui
2016-09-29 10:10 ` [PATCH v3 0/4] implement vcpu preempted check Peter Zijlstra
2016-09-29 10:23 ` Christian Borntraeger
2016-09-29 10:31 ` Peter Zijlstra
2016-09-30 5:03 ` Pan Xinhui
2016-09-30 6:58 ` Paolo Bonzini
2016-09-30 8:52 ` Pan Xinhui
2016-09-30 9:08 ` Paolo Bonzini
2016-09-30 9:31 ` Pan Xinhui
2016-09-30 10:44 ` Christian Borntraeger
2016-09-29 10:40 ` Christian Borntraeger
2016-09-29 11:05 ` Christian Borntraeger
2016-09-30 4:00 ` Pan Xinhui
2016-10-05 11:00 ` Christian Borntraeger
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1469101514-49475-2-git-send-email-xinhui.pan@linux.vnet.ibm.com \
--to=xinhui.pan@linux.vnet.ibm.com \
--cc=benh@kernel.crashing.org \
--cc=bsingharora@gmail.com \
--cc=jgross@suse.com \
--cc=kernellwp@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mingo@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=paulmck@linux.vnet.ibm.com \
--cc=paulus@samba.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=virtualization@lists.linux-foundation.org \
--cc=will.deacon@arm.com \
--cc=xen-devel-request@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).