linux-5.15/kswapd_try_to_sleep() の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• linux-5.15/kswapd_try_to_sleep() へ行く。
• linux-5.15/kswapd_try_to_sleep() の差分を削除

#author("2025-09-11T16:25:35+09:00","default:guest","guest")
#author("2025-09-11T17:04:10+09:00","default:guest","guest")
*参照元 [#vd9b0e58]
#backlinks

*説明 [#h80606b8]
-パス: [[linux-5.15/mm/vmscan.c]]

-FIXME: これは何？
--説明


**引数 [#s7be8084]
-pg_data_t *pgdat
--
--[[linux-5.15/pg_data_t]]
-int alloc_order
--
-int reclaim_order
--
-unsigned int highest_zoneidx
--
--メモリを確保する最大のゾーンインデックス値。この値以下のゾーンがチェック対象です。


**返り値 [#h35fa71c]
-なし


**参考 [#q809dd11]


*実装 [#v851d86e]

 static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_order,
 				unsigned int highest_zoneidx)
 {
 	long remaining = 0;
 	DEFINE_WAIT(wait);
 
 	if (freezing(current) || kthread_should_stop())
 		return;
 
 	prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
 
-
--[[linux-5.15/DEFINE_WAIT()]]
--[[linux-5.15/freezing()]]
--[[linux-5.15/kthread_should_stop()]]
--[[linux-5.15/prepare_to_wait()]]

 	/*
 	 * Try to sleep for a short interval. Note that kcompactd will only be
 	 * woken if it is possible to sleep for a short interval. This is
 	 * deliberate on the assumption that if reclaim cannot keep an
 	 * eligible zone balanced that it's also unlikely that compaction will
 	 * succeed.
 	 */
 	if (prepare_kswapd_sleep(pgdat, reclaim_order, highest_zoneidx)) {
-
--[[linux-5.15/prepare_kswapd_sleep()]]

 		/*
 		 * Compaction records what page blocks it recently failed to
 		 * isolate pages from and skips them in the future scanning.
 		 * When kswapd is going to sleep, it is reasonable to assume
 		 * that pages and compaction may succeed so reset the cache.
 		 */
 		reset_isolation_suitable(pgdat);
 
-
--[[linux-5.15/reset_isolation_suitable()]]

 		/*
 		 * We have freed the memory, now we should compact it to make
 		 * allocation of the requested order possible.
 		 */
 		wakeup_kcompactd(pgdat, alloc_order, highest_zoneidx);
 
-
--[[linux-5.15/wakeup_kcompactd()]]

 		remaining = schedule_timeout(HZ/10);
 
-
--[[linux-5.15/schedule_timeout()]]

 		/*
 		 * If woken prematurely then reset kswapd_highest_zoneidx and
 		 * order. The values will either be from a wakeup request or
 		 * the previous request that slept prematurely.
 		 */
 		if (remaining) {
 			WRITE_ONCE(pgdat->kswapd_highest_zoneidx,
 					kswapd_highest_zoneidx(pgdat,
 							highest_zoneidx));
 
 			if (READ_ONCE(pgdat->kswapd_order) < reclaim_order)
 				WRITE_ONCE(pgdat->kswapd_order, reclaim_order);
 		}
 
 		finish_wait(&pgdat->kswapd_wait, &wait);
 		prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
-
--[[linux-5.15/WRITE_ONCE()]]
--[[linux-5.15/kswapd_highest_zoneidx()]]
--[[linux-5.15/READ_ONCE()]]
--[[linux-5.15/finish_wait()]]
--[[linux-5.15/prepare_to_wait()]]

 	}
 
 	/*
 	 * After a short sleep, check if it was a premature sleep. If not, then
 	 * go fully to sleep until explicitly woken up.
 	 */
 	if (!remaining &&
 	    prepare_kswapd_sleep(pgdat, reclaim_order, highest_zoneidx)) {
 		trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
 
-
--[[linux-5.15/prepare_kswapd_sleep()]]
--[[linux-5.15/trace_mm_vmscan_kswapd_sleep()]]

 		/*
 		 * vmstat counters are not perfectly accurate and the estimated
 		 * value for counters such as NR_FREE_PAGES can deviate from the
 		 * true value by nr_online_cpus * threshold. To avoid the zone
 		 * watermarks being breached while under pressure, we reduce the
 		 * per-cpu vmstat threshold while kswapd is awake and restore
 		 * them before going back to sleep.
 		 */
 		set_pgdat_percpu_threshold(pgdat, calculate_normal_threshold);
 
 		if (!kthread_should_stop())
 			schedule();
 
 		set_pgdat_percpu_threshold(pgdat, calculate_pressure_threshold);
-
--[[linux-5.15/set_pgdat_percpu_threshold()]]
--[[linux-5.15/kthread_should_stop()]]

 	} else {
 		if (remaining)
 			count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY);
 		else
 			count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY);
 	}
 	finish_wait(&pgdat->kswapd_wait, &wait);
 }

-
--[[linux-5.15/count_vm_event()]]
--[[linux-5.15/finish_wait()]]


*コメント [#y7113d60]