[PATCH] drm/xe/xe_svm: Only count unique pagefaults

[Jonathan Cavitt <jonathan.cavitt@intel.com>]

The function __xe_svm_handle_pagefault increments the value of
XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT every time it is called by
xe_svm_handle_pagefault.  However, if __xe_svm_handle_pagefault returns
-EAGAIN, it can be called again in a loop, resulting in
XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT being incremented multiple times for
the same pagefault instance.  This can occur if, for example,
xe_svm_garbage_collector return -EAGAIN.

It does not make sense to increment the SVM pagefault count more than
once per pagefault, so only increment it once per call to
xe_svm_handle_pagefault.

Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Cc: Peter Senna <peter.senna@intel.com>
Cc: Ayaz A Siddiqui <ayaz.siddiqui@intel.com>
Cc: Varun Gupta <varun.gupta@intel.com>
---
 drivers/gpu/drm/xe/xe_svm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index 93550c7c84ac..245ffa6330bb 100644
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -1026,8 +1026,6 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
 	lockdep_assert_held_write(&vm->lock);
 	xe_assert(vm->xe, xe_vma_is_cpu_addr_mirror(vma));
 
-	xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT, 1);
-
 retry:
 	/* Always process UNMAPs first so view SVM ranges is current */
 	err = xe_svm_garbage_collector(vm);
@@ -1178,6 +1176,8 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
 			    bool atomic)
 {
 	int need_vram, ret;
+
+	xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT, 1);
 retry:
 	need_vram = xe_vma_need_vram_for_atomic(vm->xe, vma, atomic);
 	if (need_vram < 0)
-- 
2.43.0