3  * Manage cache of swap slots to be used for and returned from
25  * The swap slots cache is protected by a mutex instead of
43 /* Serialize swap slots cache enable/disable operations */
116 	/* if global pool of slot caches too low, deactivate cache */  in check_cache_active()
126 	struct swap_slots_cache *cache;  in alloc_swap_slot_cache()  local
155 	cache = &per_cpu(swp_slots, cpu);  in alloc_swap_slot_cache()
156 	if (cache->slots || cache->slots_ret) {  in alloc_swap_slot_cache()
157 		/* cache already allocated */  in alloc_swap_slot_cache()
166 	if (!cache->lock_initialized) {  in alloc_swap_slot_cache()
167 		mutex_init(&cache->alloc_lock);  in alloc_swap_slot_cache()
168 		spin_lock_init(&cache->free_lock);  in alloc_swap_slot_cache()
169 		cache->lock_initialized = true;  in alloc_swap_slot_cache()
171 	cache->nr = 0;  in alloc_swap_slot_cache()
172 	cache->cur = 0;  in alloc_swap_slot_cache()
173 	cache->n_ret = 0;  in alloc_swap_slot_cache()
176 	 * !cache->slots or !cache->slots_ret to know if it is safe to acquire  in alloc_swap_slot_cache()
177 	 * the corresponding lock and use the cache.  Memory barrier below  in alloc_swap_slot_cache()
181 	cache->slots = slots;  in alloc_swap_slot_cache()
182 	cache->slots_ret = slots_ret;  in alloc_swap_slot_cache()
190 	struct swap_slots_cache *cache;  in drain_slots_cache_cpu()  local
194 	cache = &per_cpu(swp_slots, cpu);  in drain_slots_cache_cpu()
195 	trace_android_rvh_drain_slots_cache_cpu(cache, type,  in drain_slots_cache_cpu()
197 	trace_android_vh_drain_slots_cache_cpu(cache, type,  in drain_slots_cache_cpu()
201 	if ((type & SLOTS_CACHE) && cache->slots) {  in drain_slots_cache_cpu()
202 		mutex_lock(&cache->alloc_lock);  in drain_slots_cache_cpu()
203 		swapcache_free_entries(cache->slots + cache->cur, cache->nr);  in drain_slots_cache_cpu()
204 		cache->cur = 0;  in drain_slots_cache_cpu()
205 		cache->nr = 0;  in drain_slots_cache_cpu()
206 		if (free_slots && cache->slots) {  in drain_slots_cache_cpu()
207 			kvfree(cache->slots);  in drain_slots_cache_cpu()
208 			cache->slots = NULL;  in drain_slots_cache_cpu()
210 		mutex_unlock(&cache->alloc_lock);  in drain_slots_cache_cpu()
212 	if ((type & SLOTS_CACHE_RET) && cache->slots_ret) {  in drain_slots_cache_cpu()
213 		spin_lock_irq(&cache->free_lock);  in drain_slots_cache_cpu()
214 		swapcache_free_entries(cache->slots_ret, cache->n_ret);  in drain_slots_cache_cpu()
215 		cache->n_ret = 0;  in drain_slots_cache_cpu()
216 		if (free_slots && cache->slots_ret) {  in drain_slots_cache_cpu()
217 			slots = cache->slots_ret;  in drain_slots_cache_cpu()
218 			cache->slots_ret = NULL;  in drain_slots_cache_cpu()
220 		spin_unlock_irq(&cache->free_lock);  in drain_slots_cache_cpu()
233 	 *	   left over slots are in cache when we remove  in __drain_swap_slots_cache()
235 	 *      2) disabling of swap slot cache, when we run low  in __drain_swap_slots_cache()
250 	 * fill any swap slots in slots cache of such cpu.  in __drain_swap_slots_cache()
273 		if (WARN_ONCE(ret < 0, "Cache allocation failed (%s), operating "  in enable_swap_slots_cache()
274 				       "without swap slots cache.\n", __func__))  in enable_swap_slots_cache()
285 /* called with swap slot cache's alloc lock held */
286 static int refill_swap_slots_cache(struct swap_slots_cache *cache)  in refill_swap_slots_cache()  argument
288 	if (!use_swap_slot_cache || cache->nr)  in refill_swap_slots_cache()
291 	cache->cur = 0;  in refill_swap_slots_cache()
293 		cache->nr = get_swap_pages(SWAP_SLOTS_CACHE_SIZE,  in refill_swap_slots_cache()
294 					   cache->slots, 1);  in refill_swap_slots_cache()
296 	return cache->nr;  in refill_swap_slots_cache()
301 	struct swap_slots_cache *cache;  in free_swap_slot()  local
304 	cache = raw_cpu_ptr(&swp_slots);  in free_swap_slot()
305 	trace_android_rvh_free_swap_slot(entry, cache, &skip);  in free_swap_slot()
306 	trace_android_vh_free_swap_slot(entry, cache, &skip);  in free_swap_slot()
309 	if (likely(use_swap_slot_cache && cache->slots_ret)) {  in free_swap_slot()
310 		spin_lock_irq(&cache->free_lock);  in free_swap_slot()
311 		/* Swap slots cache may be deactivated before acquiring lock */  in free_swap_slot()
312 		if (!use_swap_slot_cache || !cache->slots_ret) {  in free_swap_slot()
313 			spin_unlock_irq(&cache->free_lock);  in free_swap_slot()
316 		if (cache->n_ret >= SWAP_SLOTS_CACHE_SIZE) {  in free_swap_slot()
323 			swapcache_free_entries(cache->slots_ret, cache->n_ret);  in free_swap_slot()
324 			cache->n_ret = 0;  in free_swap_slot()
326 		cache->slots_ret[cache->n_ret++] = entry;  in free_swap_slot()
327 		spin_unlock_irq(&cache->free_lock);  in free_swap_slot()
339 	struct swap_slots_cache *cache;  in get_swap_page()  local
358 	 * mutex cache->alloc_lock.  in get_swap_page()
360 	 * The alloc path here does not touch cache->slots_ret  in get_swap_page()
361 	 * so cache->free_lock is not taken.  in get_swap_page()
363 	cache = raw_cpu_ptr(&swp_slots);  in get_swap_page()
365 	if (likely(check_cache_active() && cache->slots)) {  in get_swap_page()
366 		mutex_lock(&cache->alloc_lock);  in get_swap_page()
367 		if (cache->slots) {  in get_swap_page()
369 			if (cache->nr) {  in get_swap_page()
370 				entry = cache->slots[cache->cur];  in get_swap_page()
371 				cache->slots[cache->cur++].val = 0;  in get_swap_page()
372 				cache->nr--;  in get_swap_page()
373 			} else if (refill_swap_slots_cache(cache)) {  in get_swap_page()
377 		mutex_unlock(&cache->alloc_lock);  in get_swap_page()