From 04d6dbb55301a29aeb9a197e6b0012cdc265f1e4 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Sun, 4 Aug 2024 14:39:34 -0700 Subject: [PATCH] xfs: revert AIL TASK_KILLABLE threshold In commit 9adf40249e6c, we changed the behavior of the AIL thread to set its own task state to KILLABLE whenever the timeout value is nonzero. Unfortunately, this missed the fact that xfsaild_push will return 50ms (aka a longish sleep) when we reach the push target or the AIL becomes empty, so xfsaild goes to sleep for a long period of time in uninterruptible D state. This results in artificially high load averages because KILLABLE processes are UNINTERRUPTIBLE, which contributes to load average even though the AIL is asleep waiting for someone to interrupt it. It's not blocked on IOs or anything, but people scrap ps for processes that look like they're stuck in D state, so restore the previous threshold. Fixes: 9adf40249e6c ("xfs: AIL doesn't need manual pushing") Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Chandan Babu R --- fs/xfs/xfs_trans_ail.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index 0fafcc9f3dbe..8ede9d099d1f 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -644,7 +644,12 @@ xfsaild( set_freezable(); while (1) { - if (tout) + /* + * Long waits of 50ms or more occur when we've run out of items + * to push, so we only want uninterruptible state if we're + * actually blocked on something. + */ + if (tout && tout <= 20) set_current_state(TASK_KILLABLE|TASK_FREEZABLE); else set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);