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, boqun.feng@gmail.com,
borntraeger@de.ibm.com, rkrcmar@redhat.com,
Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Subject: [PATCH v5 5/9] x86, paravirt: Add interface to support kvm/xen vcpu preempted check
Date: Thu, 20 Oct 2016 17:27:50 -0400 [thread overview]
Message-ID: <1476998874-2089-6-git-send-email-xinhui.pan@linux.vnet.ibm.com> (raw)
In-Reply-To: <1476998874-2089-1-git-send-email-xinhui.pan@linux.vnet.ibm.com>
This is to fix some lock holder preemption issues. Some other locks
implementation do a spin loop before acquiring the lock itself.
Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It
takes the cpu as parameter and return true if the cpu is preempted.
Then kernel can break the spin loops upon on the retval of
vcpu_is_preempted.
As kernel has used this interface, So lets support it.
To deal with kernel and kvm/xen, add vcpu_is_preempted into struct
pv_lock_ops.
Then kvm or xen could provide their own implementation to support
vcpu_is_preempted.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
---
arch/x86/include/asm/paravirt_types.h | 2 ++
arch/x86/include/asm/spinlock.h | 8 ++++++++
arch/x86/kernel/paravirt-spinlocks.c | 6 ++++++
3 files changed, 16 insertions(+)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 0f400c0..38c3bb7 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -310,6 +310,8 @@ struct pv_lock_ops {
void (*wait)(u8 *ptr, u8 val);
void (*kick)(int cpu);
+
+ bool (*vcpu_is_preempted)(int cpu);
};
/* This contains all the paravirt structures: we get a convenient
diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 921bea7..0526f59 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -26,6 +26,14 @@
extern struct static_key paravirt_ticketlocks_enabled;
static __always_inline bool static_key_false(struct static_key *key);
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+#define vcpu_is_preempted vcpu_is_preempted
+static inline bool vcpu_is_preempted(int cpu)
+{
+ return pv_lock_ops.vcpu_is_preempted(cpu);
+}
+#endif
+
#include <asm/qspinlock.h>
/*
diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 2c55a00..2f204dd 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -21,12 +21,18 @@ bool pv_is_native_spin_unlock(void)
__raw_callee_save___native_queued_spin_unlock;
}
+static bool native_vcpu_is_preempted(int cpu)
+{
+ return 0;
+}
+
struct pv_lock_ops pv_lock_ops = {
#ifdef CONFIG_SMP
.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
.queued_spin_unlock = PV_CALLEE_SAVE(__native_queued_spin_unlock),
.wait = paravirt_nop,
.kick = paravirt_nop,
+ .vcpu_is_preempted = native_vcpu_is_preempted,
#endif /* SMP */
};
EXPORT_SYMBOL(pv_lock_ops);
--
2.4.11
next prev parent reply other threads:[~2016-10-20 17:31 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-20 21:27 [PATCH v5 0/9] implement vcpu preempted check Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 1/9] kernel/sched: introduce vcpu preempted check interface Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 2/9] locking/osq: Drop the overload of osq_lock() Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 3/9] kernel/locking: Drop the overload of {mutex, rwsem}_spin_on_owner Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 4/9] powerpc/spinlock: support vcpu preempted check Pan Xinhui
2016-10-20 21:27 ` Pan Xinhui [this message]
2016-10-20 21:27 ` [PATCH v5 6/9] x86, kvm: " Pan Xinhui
2016-10-24 8:08 ` xinhui
2016-10-20 21:27 ` [PATCH v5 7/9] x86, xen: " Pan Xinhui
2016-10-21 5:08 ` Juergen Gross
2016-10-20 21:27 ` [PATCH v5 8/9] s390/spinlock: Provide vcpu_is_preempted Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 9/9] Documentation: virtual: kvm: Support vcpu preempted check Pan Xinhui
2016-10-21 1:23 ` Boqun Feng
2016-10-21 1:42 ` Pan Xinhui
2016-10-21 11:27 ` David Laight
2016-10-21 18:39 ` rkrcmar
2016-10-24 2:46 ` xinhui
2016-10-24 14:42 ` Paolo Bonzini
2016-10-24 15:05 ` rkrcmar
2016-10-24 2:44 ` xinhui
2016-10-24 8:12 ` xinhui
2016-10-21 5:40 ` [PATCH v5 0/9] implement " Peter Zijlstra
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=1476998874-2089-6-git-send-email-xinhui.pan@linux.vnet.ibm.com \
--to=xinhui.pan@linux.vnet.ibm.com \
--cc=benh@kernel.crashing.org \
--cc=boqun.feng@gmail.com \
--cc=borntraeger@de.ibm.com \
--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=rkrcmar@redhat.com \
--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).