[Intel-gfx] [PATCH v3 01/14] drm/i915: Give each sw_fence its own lockclass

[Chris Wilson]

On Mon, Nov 14, 2016 at 04:48:00PM +0200, Joonas Lahtinen wrote:
> On ma, 2016-11-14 at 08:56 +0000, Chris Wilson wrote:
> > +	static struct lock_class_key __key; 			\
> 
> When lockdep is disabled, this becomes zero size. We might still get
> rid of the #fence strings, with some #ifdef, did you measure the
> impact? I remember some for_each_engine_masked cry over bytes.

I was copying mutex_init. To avoid it is not just a little ifdeffery :|

The strings currently cost us around 160 bytes of text.

   text	   data	    bss	    dec	    hex	filename
1222524	   5077	    608	1228209	 12bdb1	drivers/gpu/drm/i915/i915.ko
1222364	   5077	    608	1228049	 12bd11 drivers/gpu/drm/i915/i915.ko

diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
index 65fded24a9eb..804af5766650 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.c
+++ b/drivers/gpu/drm/i915/i915_sw_fence.c
@@ -110,6 +110,9 @@ static void i915_sw_fence_await(struct i915_sw_fence *fence)
        WARN_ON(atomic_inc_return(&fence->pending) <= 1);
 }
 
+#ifndef CONFIG_LOCKDEP
+static
+#endif
 void __i915_sw_fence_init(struct i915_sw_fence *fence,
                          i915_sw_fence_notify_t fn,
                          const char *name,
@@ -123,6 +126,16 @@ void __i915_sw_fence_init(struct i915_sw_fence *fence,
        fence->flags = (unsigned long)fn;
 }
 
+#ifndef CONFIG_LOCKDEP
+void i915_sw_fence_init(struct i915_sw_fence *fence,
+                       i915_sw_fence_notify_t fn)
+{
+       static struct lock_class_key __key;
+
+       __i915_sw_fence_init(fence, fn, NULL, &__key);
+}
+#endif
+
 void i915_sw_fence_commit(struct i915_sw_fence *fence)
 {
        i915_sw_fence_complete(fence);
diff --git a/drivers/gpu/drm/i915/i915_sw_fence.h b/drivers/gpu/drm/i915/i915_sw_fence.h
index 23748a1ae6ae..d8510a4b02bd 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.h
+++ b/drivers/gpu/drm/i915/i915_sw_fence.h
@@ -40,6 +40,7 @@ typedef int (*i915_sw_fence_notify_t)(struct i915_sw_fence *,
                                      enum i915_sw_fence_notify state);
 #define __i915_sw_fence_call __aligned(4)
 
+#ifdef CONFIG_LOCKDEP
 void __i915_sw_fence_init(struct i915_sw_fence *fence,
                          i915_sw_fence_notify_t fn,
                          const char *name,
@@ -49,6 +50,10 @@ void __i915_sw_fence_init(struct i915_sw_fence *fence,
                                                                \
        __i915_sw_fence_init((fence), (fn), #fence, &__key);    \
 } while (0)
+#else
+void i915_sw_fence_init(struct i915_sw_fence *fence,
+                       i915_sw_fence_notify_t fn);
+#endif
 
 void i915_sw_fence_commit(struct i915_sw_fence *fence);
 

Can we do that more neatly?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre