Attachment 645175 Details for Bug 867433 – patch to reduce the async thread count to be sane

[patch] patch to reduce the async thread count to be sane

async.patch (text/plain), 1.52 KB, created by Neil Horman on 2012-11-14 20:51:59 UTC

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Creator: Neil Horman

Created: 2012-11-14 20:51:59 UTC

Size: 1.52 KB

patch

obsolete

>diff --git a/kernel/async.c b/kernel/async.c
>index a7239a7..3a2b095 100644
>--- a/kernel/async.c
>+++ b/kernel/async.c
>@@ -369,23 +369,15 @@ static int async_thread(void *unused)
> 		else
> 			ret = schedule_timeout(HZ);
> 
>-		if (ret == 0) {
>-			/*
>-			 * we timed out, this means we as thread are redundant.
>-			 * we sign off and die, but we to avoid any races there
>-			 * is a last-straw check to see if work snuck in.
>-			 */
>-			atomic_dec(&thread_count);
>-			wmb(); /* manager must see our departure first */
>-			if (list_empty(&async_pending))
>-				break;
>-			/*
>-			 * woops work came in between us timing out and us
>-			 * signing off; we need to stay alive and keep working.
>-			 */
>-			atomic_inc(&thread_count);
>-		}
>+		/*
>+ 		 * Exit if theres no more work for this thread
>+ 		 * to do
>+ 		 */
>+		if ((ret == 0) && list_empty(&async_pending))
>+			break;
> 	}
>+	wmb();
>+	atomic_dec(&thread_count);
> 	remove_wait_queue(&async_new, &wq);
> 
> 	return 0;
>@@ -393,6 +385,8 @@ static int async_thread(void *unused)
> 
> static int async_manager_thread(void *unused)
> {
>+	int ncpus = num_online_cpus();
>+	int max_threads = min(MAX_THREADS, ncpus);
> 	DECLARE_WAITQUEUE(wq, current);
> 	add_wait_queue(&async_new, &wq);
> 
>@@ -404,8 +398,9 @@ static int async_manager_thread(void *unused)
> 		tc = atomic_read(&thread_count);
> 		rmb();
> 		ec = atomic_read(&entry_count);
>+		ec = min(ec, max_threads);
> 
>-		while (tc < ec && tc < MAX_THREADS) {
>+		while (tc < ec) {
> 			if (IS_ERR(kthread_run(async_thread, NULL, "async/%i",
> 					       tc))) {
> 				msleep(100);

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Attachments on bug 867433: 628827 | 645175