From 66a0d8204f775bd32bad68c42d4fec223272f9e0 Mon Sep 17 00:00:00 2001
From: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Date: Mon, 18 Oct 2021 11:48:33 -0400
Subject: [PATCH] zink: reduce hashed region of zink_descriptor_layout_key

only the first 3 members of VkDescriptorSetLayoutBinding are useful here

Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13483>
---
 src/gallium/drivers/zink/zink_descriptors.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/zink/zink_descriptors.c b/src/gallium/drivers/zink/zink_descriptors.c
index a8272b2fea1..4d946e7d1a3 100644
--- a/src/gallium/drivers/zink/zink_descriptors.c
+++ b/src/gallium/drivers/zink/zink_descriptors.c
@@ -388,7 +388,9 @@ hash_descriptor_layout(const void *key)
    uint32_t hash = 0;
    const struct zink_descriptor_layout_key *k = key;
    hash = XXH32(&k->num_bindings, sizeof(unsigned), hash);
-   hash = XXH32(k->bindings, k->num_bindings * sizeof(VkDescriptorSetLayoutBinding), hash);
+   /* only hash first 3 members: no holes and the rest are always constant */
+   for (unsigned i = 0; i < k->num_bindings; i++)
+      hash = XXH32(&k->bindings[i], offsetof(VkDescriptorSetLayoutBinding, stageFlags), hash);
 
    return hash;
 }