From bd9ea05ebb5b0bf145941dd6be04aa68f100bb20 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Fri, 19 Jan 2024 11:25:56 -0500
Subject: [PATCH] gpu: Evict stale textures from the cache

This is straightforward. If a texture hasn't been used for 4 seconds,
we consider it stale, and drop it the next time gc comes around.

The choice of 4 seconds is arbitrary.

Fixes: #6346
---
 gsk/gpu/gskgpudevice.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/gsk/gpu/gskgpudevice.c b/gsk/gpu/gskgpudevice.c
index 73d7c3fce5..332754189a 100644
--- a/gsk/gpu/gskgpudevice.c
+++ b/gsk/gpu/gskgpudevice.c
@@ -20,6 +20,8 @@ G_STATIC_ASSERT (MAX_ATLAS_ITEM_SIZE < ATLAS_SIZE);
 
 #define CACHE_GC_TIMEOUT 15  /* seconds */
 
+#define CACHE_MAX_AGE (G_TIME_SPAN_SECOND * 4)  /* 4 seconds, in µs */
+
 typedef struct _GskGpuCached GskGpuCached;
 typedef struct _GskGpuCachedClass GskGpuCachedClass;
 typedef struct _GskGpuCachedAtlas GskGpuCachedAtlas;
@@ -64,6 +66,8 @@ struct _GskGpuCached
   GskGpuCachedAtlas *atlas;
   GskGpuCached *next;
   GskGpuCached *prev;
+
+  gint64 timestamp;
 };
 
 static void
@@ -120,7 +124,7 @@ gsk_gpu_cached_use (GskGpuDevice *device,
                     GskGpuCached *cached,
                     gint64        timestamp)
 {
-  /* FIXME */
+  cached->timestamp = timestamp;
 }
 
 /* }}} */
@@ -207,8 +211,7 @@ gsk_gpu_cached_texture_should_collect (GskGpuDevice *device,
                                        GskGpuCached *cached,
                                        gint64        timestamp)
 {
-  /* FIXME */
-  return FALSE;
+  return timestamp - cached->timestamp > CACHE_MAX_AGE;
 }
 
 static const GskGpuCachedClass GSK_GPU_CACHED_TEXTURE_CLASS =