Attachment 1445953 Details for Bug 1579155 – UNTESTED patch to change nv_spinlock_t

[patch] UNTESTED patch to change nv_spinlock_t

0001-rt-use-raw_spinlock_t-as-nv_spinlock_t-on-PREEMPT_RT.patch (text/plain), 1.97 KB, created by Clark Williams on 2018-05-30 16:15:04 UTC

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Creator: Clark Williams

Created: 2018-05-30 16:15:04 UTC

Size: 1.97 KB

patch

obsolete

>From ac29d2f4c3d42891b052373c82c5dd9284823ec8 Mon Sep 17 00:00:00 2001
>From: Clark Williams <williams@redhat.com>
>Date: Wed, 30 May 2018 11:05:47 -0500
>Subject: [PATCH] rt: use raw_spinlock_t as nv_spinlock_t on PREEMPT_RT kernels
>
>On PREEMPT_RT kernels, spinlock_t is converted to rt_mutex_t which is a
>sleeping lock which causes problems with atomic contexts. The
>raw_spinlock_t type is available for locks required for critical
>sections that have atomic context. Note that raw spinlocks are unbounded
>so holding one for a long period will cause latency spikes. 
>
>Signed-off-by: Clark Williams <williams@redhat.com>
>---
> common/inc/nv-lock.h | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
>diff --git a/common/inc/nv-lock.h b/common/inc/nv-lock.h
>index f2ef557911a9..43e4537e07a7 100644
>--- a/common/inc/nv-lock.h
>+++ b/common/inc/nv-lock.h
>@@ -21,6 +21,17 @@
> #include <asm/semaphore.h>
> #endif
> 
>+#if defined(NV_CONFIG_PREEMPT_RT)
>+typedef raw_spinlock_t            nv_spinlock_t;
>+#define NV_SPIN_LOCK_INIT(lock)   raw_spin_lock_init(lock)
>+#define NV_SPIN_LOCK_IRQ(lock)    raw_spin_lock_irq(lock)
>+#define NV_SPIN_UNLOCK_IRQ(lock)  raw_spin_unlock_irq(lock)
>+#define NV_SPIN_LOCK_IRQSAVE(lock,flags) raw_spin_lock_irqsave(lock,flags)
>+#define NV_SPIN_UNLOCK_IRQRESTORE(lock,flags) raw_spin_unlock_irqrestore(lock,flags)
>+#define NV_SPIN_LOCK(lock)        raw_spin_lock(lock)
>+#define NV_SPIN_UNLOCK(lock)      raw_spin_unlock(lock)
>+#define NV_SPIN_UNLOCK_WAIT(lock) raw_spin_unlock_wait(lock)
>+#else
> typedef spinlock_t                nv_spinlock_t;
> #define NV_SPIN_LOCK_INIT(lock)   spin_lock_init(lock)
> #define NV_SPIN_LOCK_IRQ(lock)    spin_lock_irq(lock)
>@@ -30,6 +41,7 @@ typedef spinlock_t                nv_spinlock_t;
> #define NV_SPIN_LOCK(lock)        spin_lock(lock)
> #define NV_SPIN_UNLOCK(lock)      spin_unlock(lock)
> #define NV_SPIN_UNLOCK_WAIT(lock) spin_unlock_wait(lock)
>+#endif
> 
> #if defined(NV_CONFIG_PREEMPT_RT)
> #define NV_INIT_SEMA(sema, val) sema_init(sema,val)
>-- 
>2.17.0
>

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Attachments on bug 1579155: 1445953