drm/msm: Add mmu prealloc tracepoint

So we can monitor how many pages are getting preallocated vs how many
get used.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Tested-by: Antonino Maniscalco <antomani103@gmail.com>
Reviewed-by: Antonino Maniscalco <antomani103@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/661521/

Author: robclark

drivers/gpu/drm/msm/msm_gpu_trace.h

@@ -205,6 +205,20 @@ TRACE_EVENT(msm_gpu_preemption_irq,
 		TP_printk("preempted to %u", __entry->ring_id)
 );
 
+TRACE_EVENT(msm_mmu_prealloc_cleanup,
+		TP_PROTO(u32 count, u32 remaining),
+		TP_ARGS(count, remaining),
+		TP_STRUCT__entry(
+			__field(u32, count)
+			__field(u32, remaining)
+			),
+		TP_fast_assign(
+			__entry->count = count;
+			__entry->remaining = remaining;
+			),
+		TP_printk("count=%u, remaining=%u", __entry->count, __entry->remaining)
+);
+
 #endif
 
 #undef TRACE_INCLUDE_PATH

drivers/gpu/drm/msm/msm_iommu.c

@@ -8,6 +8,7 @@
 #include <linux/io-pgtable.h>
 #include <linux/kmemleak.h>
 #include "msm_drv.h"
+#include "msm_gpu_trace.h"
 #include "msm_mmu.h"
 
 struct msm_iommu {
@@ -346,6 +347,9 @@ msm_iommu_pagetable_prealloc_cleanup(struct msm_mmu *mmu, struct msm_mmu_preallo
 	struct kmem_cache *pt_cache = get_pt_cache(mmu);
 	uint32_t remaining_pt_count = p->count - p->ptr;
 
+	if (p->count > 0)
+		trace_msm_mmu_prealloc_cleanup(p->count, remaining_pt_count);
+
 	kmem_cache_free_bulk(pt_cache, remaining_pt_count, &p->pages[p->ptr]);
 	kvfree(p->pages);
 }