1 // SPDX-License-Identifier: MIT 2 /* 3 * Copyright © 2024 Intel Corporation 4 */ 5 6 #include <linux/shrinker.h> 7 8 #include <drm/drm_managed.h> 9 #include <drm/ttm/ttm_backup.h> 10 #include <drm/ttm/ttm_bo.h> 11 #include <drm/ttm/ttm_tt.h> 12 13 #include "xe_bo.h" 14 #include "xe_pm.h" 15 #include "xe_shrinker.h" 16 17 /** 18 * struct xe_shrinker - per-device shrinker 19 * @xe: Back pointer to the device. 20 * @lock: Lock protecting accounting. 21 * @shrinkable_pages: Number of pages that are currently shrinkable. 22 * @purgeable_pages: Number of pages that are currently purgeable. 23 * @shrink: Pointer to the mm shrinker. 24 * @pm_worker: Worker to wake up the device if required. 25 */ 26 struct xe_shrinker { 27 struct xe_device *xe; 28 rwlock_t lock; 29 long shrinkable_pages; 30 long purgeable_pages; 31 struct shrinker *shrink; 32 struct work_struct pm_worker; 33 }; 34 35 static struct xe_shrinker *to_xe_shrinker(struct shrinker *shrink) 36 { 37 return shrink->private_data; 38 } 39 40 /** 41 * xe_shrinker_mod_pages() - Modify shrinker page accounting 42 * @shrinker: Pointer to the struct xe_shrinker. 43 * @shrinkable: Shrinkable pages delta. May be negative. 44 * @purgeable: Purgeable page delta. May be negative. 45 * 46 * Modifies the shrinkable and purgeable pages accounting. 47 */ 48 void 49 xe_shrinker_mod_pages(struct xe_shrinker *shrinker, long shrinkable, long purgeable) 50 { 51 write_lock(&shrinker->lock); 52 shrinker->shrinkable_pages += shrinkable; 53 shrinker->purgeable_pages += purgeable; 54 write_unlock(&shrinker->lock); 55 } 56 57 static s64 xe_shrinker_walk(struct xe_device *xe, 58 struct ttm_operation_ctx *ctx, 59 const struct xe_bo_shrink_flags flags, 60 unsigned long to_scan, unsigned long *scanned) 61 { 62 unsigned int mem_type; 63 s64 freed = 0, lret; 64 65 for (mem_type = XE_PL_SYSTEM; mem_type <= XE_PL_TT; ++mem_type) { 66 struct ttm_resource_manager *man = ttm_manager_type(&xe->ttm, mem_type); 67 struct ttm_bo_lru_cursor curs; 68 struct ttm_buffer_object *ttm_bo; 69 struct ttm_lru_walk_arg arg = { 70 .ctx = ctx, 71 .trylock_only = true, 72 }; 73 74 if (!man || !man->use_tt) 75 continue; 76 77 ttm_bo_lru_for_each_reserved_guarded(&curs, man, &arg, ttm_bo) { 78 if (!ttm_bo_shrink_suitable(ttm_bo, ctx)) 79 continue; 80 81 lret = xe_bo_shrink(ctx, ttm_bo, flags, scanned); 82 if (lret < 0) 83 return lret; 84 85 freed += lret; 86 if (*scanned >= to_scan) 87 break; 88 } 89 /* Trylocks should never error, just fail. */ 90 xe_assert(xe, !IS_ERR(ttm_bo)); 91 } 92 93 return freed; 94 } 95 96 static unsigned long 97 xe_shrinker_count(struct shrinker *shrink, struct shrink_control *sc) 98 { 99 struct xe_shrinker *shrinker = to_xe_shrinker(shrink); 100 unsigned long num_pages; 101 bool can_backup = !!(sc->gfp_mask & __GFP_FS); 102 103 num_pages = ttm_backup_bytes_avail() >> PAGE_SHIFT; 104 read_lock(&shrinker->lock); 105 106 if (can_backup) 107 num_pages = min_t(unsigned long, num_pages, shrinker->shrinkable_pages); 108 else 109 num_pages = 0; 110 111 num_pages += shrinker->purgeable_pages; 112 read_unlock(&shrinker->lock); 113 114 return num_pages ? num_pages : SHRINK_EMPTY; 115 } 116 117 /* 118 * Check if we need runtime pm, and if so try to grab a reference if 119 * already active. If grabbing a reference fails, queue a worker that 120 * does it for us outside of reclaim, but don't wait for it to complete. 121 * If bo shrinking needs an rpm reference and we don't have it (yet), 122 * that bo will be skipped anyway. 123 */ 124 static bool xe_shrinker_runtime_pm_get(struct xe_shrinker *shrinker, bool force, 125 unsigned long nr_to_scan, bool can_backup) 126 { 127 struct xe_device *xe = shrinker->xe; 128 129 if (IS_DGFX(xe) || !xe_device_has_flat_ccs(xe) || 130 !ttm_backup_bytes_avail()) 131 return false; 132 133 if (!force) { 134 read_lock(&shrinker->lock); 135 force = (nr_to_scan > shrinker->purgeable_pages && can_backup); 136 read_unlock(&shrinker->lock); 137 if (!force) 138 return false; 139 } 140 141 if (!xe_pm_runtime_get_if_active(xe)) { 142 if (xe_rpm_reclaim_safe(xe) && !ttm_bo_shrink_avoid_wait()) { 143 xe_pm_runtime_get(xe); 144 return true; 145 } 146 queue_work(xe->unordered_wq, &shrinker->pm_worker); 147 return false; 148 } 149 150 return true; 151 } 152 153 static void xe_shrinker_runtime_pm_put(struct xe_shrinker *shrinker, bool runtime_pm) 154 { 155 if (runtime_pm) 156 xe_pm_runtime_put(shrinker->xe); 157 } 158 159 static unsigned long xe_shrinker_scan(struct shrinker *shrink, struct shrink_control *sc) 160 { 161 struct xe_shrinker *shrinker = to_xe_shrinker(shrink); 162 struct ttm_operation_ctx ctx = { 163 .interruptible = false, 164 .no_wait_gpu = ttm_bo_shrink_avoid_wait(), 165 }; 166 unsigned long nr_to_scan, nr_scanned = 0, freed = 0; 167 struct xe_bo_shrink_flags shrink_flags = { 168 .purge = true, 169 /* Don't request writeback without __GFP_IO. */ 170 .writeback = !ctx.no_wait_gpu && (sc->gfp_mask & __GFP_IO), 171 }; 172 bool runtime_pm; 173 bool purgeable; 174 bool can_backup = !!(sc->gfp_mask & __GFP_FS); 175 s64 lret; 176 177 nr_to_scan = sc->nr_to_scan; 178 179 read_lock(&shrinker->lock); 180 purgeable = !!shrinker->purgeable_pages; 181 read_unlock(&shrinker->lock); 182 183 /* Might need runtime PM. Try to wake early if it looks like it. */ 184 runtime_pm = xe_shrinker_runtime_pm_get(shrinker, false, nr_to_scan, can_backup); 185 186 if (purgeable && nr_scanned < nr_to_scan) { 187 lret = xe_shrinker_walk(shrinker->xe, &ctx, shrink_flags, 188 nr_to_scan, &nr_scanned); 189 if (lret >= 0) 190 freed += lret; 191 } 192 193 sc->nr_scanned = nr_scanned; 194 if (nr_scanned >= nr_to_scan || !can_backup) 195 goto out; 196 197 /* If we didn't wake before, try to do it now if needed. */ 198 if (!runtime_pm) 199 runtime_pm = xe_shrinker_runtime_pm_get(shrinker, true, 0, can_backup); 200 201 shrink_flags.purge = false; 202 lret = xe_shrinker_walk(shrinker->xe, &ctx, shrink_flags, 203 nr_to_scan, &nr_scanned); 204 if (lret >= 0) 205 freed += lret; 206 207 sc->nr_scanned = nr_scanned; 208 out: 209 xe_shrinker_runtime_pm_put(shrinker, runtime_pm); 210 return nr_scanned ? freed : SHRINK_STOP; 211 } 212 213 /* Wake up the device for shrinking. */ 214 static void xe_shrinker_pm(struct work_struct *work) 215 { 216 struct xe_shrinker *shrinker = 217 container_of(work, typeof(*shrinker), pm_worker); 218 219 xe_pm_runtime_get(shrinker->xe); 220 xe_pm_runtime_put(shrinker->xe); 221 } 222 223 static void xe_shrinker_fini(struct drm_device *drm, void *arg) 224 { 225 struct xe_shrinker *shrinker = arg; 226 227 xe_assert(shrinker->xe, !shrinker->shrinkable_pages); 228 xe_assert(shrinker->xe, !shrinker->purgeable_pages); 229 shrinker_free(shrinker->shrink); 230 flush_work(&shrinker->pm_worker); 231 kfree(shrinker); 232 } 233 234 /** 235 * xe_shrinker_create() - Create an xe per-device shrinker 236 * @xe: Pointer to the xe device. 237 * 238 * Return: %0 on success. Negative error code on failure. 239 */ 240 int xe_shrinker_create(struct xe_device *xe) 241 { 242 struct xe_shrinker *shrinker = kzalloc(sizeof(*shrinker), GFP_KERNEL); 243 244 if (!shrinker) 245 return -ENOMEM; 246 247 shrinker->shrink = shrinker_alloc(0, "drm-xe_gem:%s", xe->drm.unique); 248 if (!shrinker->shrink) { 249 kfree(shrinker); 250 return -ENOMEM; 251 } 252 253 INIT_WORK(&shrinker->pm_worker, xe_shrinker_pm); 254 shrinker->xe = xe; 255 rwlock_init(&shrinker->lock); 256 shrinker->shrink->count_objects = xe_shrinker_count; 257 shrinker->shrink->scan_objects = xe_shrinker_scan; 258 shrinker->shrink->private_data = shrinker; 259 shrinker_register(shrinker->shrink); 260 xe->mem.shrinker = shrinker; 261 262 return drmm_add_action_or_reset(&xe->drm, xe_shrinker_fini, shrinker); 263 } 264