From: "Seth Forshee (DigitalOcean)" <sforshee@digitalocean.com>
To: Petr Mladek <pmladek@suse.com>, Jason Wang <jasowang@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
Joe Lawrence <joe.lawrence@redhat.com>,
Josh Poimboeuf <jpoimboe@kernel.org>
Cc: virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
"Seth Forshee (DigitalOcean)" <sforshee@kernel.org>,
netdev@vger.kernel.org, live-patching@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] vhost: check for pending livepatches from vhost worker kthreads
Date: Fri, 20 Jan 2023 16:12:22 -0600 [thread overview]
Message-ID: <20230120-vhost-klp-switching-v1-2-7c2b65519c43@kernel.org> (raw)
In-Reply-To: <20230120-vhost-klp-switching-v1-0-7c2b65519c43@kernel.org>
Livepatch relies on stack checking of sleeping tasks to switch kthreads,
so a busy kthread can block a livepatch transition indefinitely. We've
seen this happen fairly often with busy vhost kthreads.
Add a check to call klp_switch_current() from vhost_worker() when a
livepatch is pending. In testing this allowed vhost kthreads to switch
immediately when they had previously blocked livepatch transitions for
long periods of time.
Signed-off-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
---
drivers/vhost/vhost.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index cbe72bfd2f1f..d8624f1f2d64 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -30,6 +30,7 @@
#include <linux/interval_tree_generic.h>
#include <linux/nospec.h>
#include <linux/kcov.h>
+#include <linux/livepatch.h>
#include "vhost.h"
@@ -366,6 +367,9 @@ static int vhost_worker(void *data)
if (need_resched())
schedule();
}
+
+ if (unlikely(klp_patch_pending(current)))
+ klp_switch_current();
}
kthread_unuse_mm(dev->mm);
return 0;
--
b4 0.10.1
next prev parent reply other threads:[~2023-01-20 22:12 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-20 22:12 [PATCH 0/2] vhost: improve livepatch switching for heavily loaded vhost worker kthreads Seth Forshee (DigitalOcean)
2023-01-20 22:12 ` [PATCH 1/2] livepatch: add an interface for safely switching kthreads Seth Forshee (DigitalOcean)
2023-01-20 22:12 ` Seth Forshee (DigitalOcean) [this message]
2023-01-24 14:17 ` [PATCH 2/2] vhost: check for pending livepatches from vhost worker kthreads Petr Mladek
2023-01-24 17:21 ` Seth Forshee
2023-01-25 11:34 ` Petr Mladek
2023-01-25 16:57 ` Seth Forshee
2023-01-26 11:16 ` Petr Mladek
2023-01-26 11:49 ` Petr Mladek
2023-01-22 8:34 ` [PATCH 0/2] vhost: improve livepatch switching for heavily loaded " Michael S. Tsirkin
2023-01-26 17:03 ` Petr Mladek
2023-01-26 21:12 ` Seth Forshee (DigitalOcean)
2023-01-27 4:43 ` Josh Poimboeuf
2023-01-27 10:37 ` Peter Zijlstra
2023-01-27 12:09 ` Petr Mladek
2023-01-27 14:37 ` Seth Forshee
2023-01-27 16:52 ` Josh Poimboeuf
2023-01-27 17:09 ` Josh Poimboeuf
2023-01-27 22:11 ` Josh Poimboeuf
2023-01-30 12:40 ` Peter Zijlstra
2023-01-30 17:50 ` Seth Forshee
2023-01-30 18:18 ` Josh Poimboeuf
2023-01-30 18:36 ` Mark Rutland
2023-01-30 19:48 ` Josh Poimboeuf
2023-01-31 1:53 ` Song Liu
2023-01-31 10:22 ` Mark Rutland
2023-01-31 16:38 ` Josh Poimboeuf
2023-02-01 11:10 ` Mark Rutland
2023-02-01 16:57 ` Josh Poimboeuf
2023-02-01 17:11 ` Mark Rutland
2023-01-30 19:59 ` Josh Poimboeuf
2023-01-31 10:02 ` Peter Zijlstra
2023-01-27 20:02 ` Seth Forshee
2023-01-27 11:19 ` Petr Mladek
2023-01-27 14:57 ` Seth Forshee
2023-01-30 9:55 ` Petr Mladek
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