From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: John Johansen <john.johansen@canonical.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Tomasz Figa <tfiga@chromium.org>,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: apparmor: global buffers spin lock may get contended
Date: Mon, 31 Oct 2022 12:52:37 +0900 [thread overview]
Message-ID: <Y19GhTg8Q/3ym/VD@google.com> (raw)
In-Reply-To: <cfd5cc6f-5943-2e06-1dbe-f4b4ad5c1fa1@canonical.com>
On (22/10/28 02:34), John Johansen wrote:
> From d026988196fdbda7234fb87bc3e4aea22edcbaf9 Mon Sep 17 00:00:00 2001
> From: John Johansen <john.johansen@canonical.com>
> Date: Tue, 25 Oct 2022 01:18:41 -0700
> Subject: [PATCH] apparmor: cache buffers on percpu list if there is lock
> contention
>
> On a heavily loaded machine there can be lock contention on the
> global buffers lock. Add a percpu list to cache buffers on when
> lock contention is encountered.
>
> When allocating buffers attempt to use cached buffers first,
> before taking the global buffers lock. When freeing buffers
> try to put them back to the global list but if contention is
> encountered, put the buffer on the percpu list.
>
> The length of time a buffer is held on the percpu list is dynamically
> adjusted based on lock contention. The amount of hold time is rapidly
> increased and slow ramped down.
>
> Signed-off-by: John Johansen <john.johansen@canonical.com>
Reported-by: Sergey Senozhatsky <senozhatsky@chromium.org>
next prev parent reply other threads:[~2022-10-31 3:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-13 13:19 apparmor: global buffers spin lock may get contended Sergey Senozhatsky
2021-08-15 9:47 ` John Johansen
2022-10-28 9:34 ` John Johansen
2022-10-31 3:52 ` Sergey Senozhatsky [this message]
2022-10-31 3:55 ` John Johansen
2022-10-31 4:04 ` Sergey Senozhatsky
2023-02-17 0:03 ` John Johansen
2023-02-17 0:08 ` [PATCH v3] " John Johansen
2023-02-17 10:44 ` Sebastian Andrzej Siewior
2023-02-20 8:42 ` John Johansen
2023-02-21 21:27 ` Anil Altinay
2023-06-26 23:35 ` Anil Altinay
[not found] ` <CACCxZWO-+M-J_enENr7q1WDcu1U8vYFoytqJxAh=x-nuP268zA@mail.gmail.com>
2023-06-27 0:31 ` John Johansen
2023-10-06 4:18 ` Sergey Senozhatsky
2023-10-17 9:21 ` [PATCH v5 0/4] apparmor: cache buffers on percpu list if there is lock, contention John Johansen
2023-10-17 9:23 ` [PATCH v5 1/4] " John Johansen
2023-10-17 9:24 ` [PATCH v5 2/4] apparmor: exponential backoff on cache buffer contention John Johansen
2023-10-17 9:25 ` [PATCH v5 3/4] apparmor: experiment with faster backoff on global buffer John Johansen
2023-10-17 9:26 ` [PATCH v5 4/4] apparmor: limit the number of buffers in percpu cache John Johansen
2023-10-26 5:13 ` [PATCH v5 0/4] apparmor: cache buffers on percpu list if there is lock, contention Sergey Senozhatsky
[not found] ` <20221030013028.3557-1-hdanton@sina.com>
2022-10-30 6:32 ` apparmor: global buffers spin lock may get contended John Johansen
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