linux-kernel - [PATCH 2/5] kmod: Remove unecessary explicit wide CPU affinity setting

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Date:	Mon, 27 Jul 2015 18:27:17 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Tejun Heo <tj@...nel.org>, Oleg Nesterov <oleg@...hat.com>,
	Christoph Lameter <cl@...ux.com>,
	Rik van Riel <riel@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 2/5] kmod: Remove unecessary explicit wide CPU affinity setting

Khelper is affine to all CPUs. Now since it creates the
call_usermodehelper_exec_[a]sync() kernel threads, those inherit the
wide affinity.

As such explicitly forcing a wide affinity from those kernel threads
is like a no-op.

Just remove it. It's needless and it breaks CPU isolation users who
rely on workqueue affinity tuning.

Cc: Rik van Riel <riel@...hat.com>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Christoph Lameter <cl@...ux.com>
Cc: Tejun Heo <tj@...nel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
---
 kernel/kmod.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 4682e91..97be0cf 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -223,9 +223,6 @@ static int call_usermodehelper_exec_async(void *data)
 	flush_signal_handlers(current, 1);
 	spin_unlock_irq(&current->sighand->siglock);
 
-	/* We can run anywhere, unlike our parent keventd(). */
-	set_cpus_allowed_ptr(current, cpu_all_mask);
-
 	/*
 	 * Our parent is keventd, which runs with elevated scheduling priority.
 	 * Avoid propagating that into the userspace child.
-- 
2.1.4

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