From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Song Bao Hua <song.bao.hua@hisilicon.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E . McKenney" <paulmck@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"Luis Claudio R. Goncalves" <lgoncalv@redhat.com>,
Seth Jennings <sjenning@redhat.com>,
Dan Streetman <ddstreet@ieee.org>,
Vitaly Wool <vitaly.wool@konsulko.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Linuxarm <linuxarm@huawei.com>
Subject: Re: [PATCH 8/8] mm/zswap: Use local lock to protect per-CPU data
Date: Wed, 20 May 2020 13:57:41 +0200 [thread overview]
Message-ID: <20200520115741.wy2qnmauxmjtrrzj@linutronix.de> (raw)
In-Reply-To: <B926444035E5E2439431908E3842AFD24B2058@DGGEMI525-MBS.china.huawei.com>
On 2020-05-20 11:13:31 [+0000], Song Bao Hua wrote:
> For example, on cpu1, once you begin to compress, you hold the percpu acomp-ctx and percpu destination buffer of CPU1, the below code makes sure you get the acomp and dstmem from the same core by disabling preemption with get_cpu_var and put_cpu_var:
> dst = get_cpu_var(zswap_dstmem);
> acomp_ctx = *this_cpu_ptr(entry->pool->acomp_ctx);
> put_cpu_var(zswap_dstmem);
>
> then there are two cases:
>
> 1. after getting dst and acomp_ctx of cpu1, you might always work in cpu1, the mutex in per-cpu acomp-ctx will guarantee two compressions won't do at the same core in parallel, and it also makes certain compression and decompression won't do at the same core in parallel. Everything is like before.
For readability I suggest not to mix per-CPU and per-CTX variables like
that. If zswap_dstmem is protected by the mutex, please make it part of
acomp_ctx.
Sebastian
next prev parent reply other threads:[~2020-05-20 11:57 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 20:19 [PATCH 0/8] Introduce local_lock() Sebastian Andrzej Siewior
2020-05-19 20:19 ` [PATCH 1/8] locking: " Sebastian Andrzej Siewior
2020-05-20 12:04 ` Peter Zijlstra
2020-05-22 11:05 ` Sebastian Andrzej Siewior
2020-05-22 13:01 ` Peter Zijlstra
2020-05-19 20:19 ` [PATCH 2/8] radix-tree: Use local_lock for protection Sebastian Andrzej Siewior
2020-05-19 20:45 ` Matthew Wilcox
2020-05-19 20:54 ` Steven Rostedt
2020-05-20 2:05 ` Matthew Wilcox
2020-05-20 10:13 ` Sebastian Andrzej Siewior
2020-05-20 10:21 ` Peter Zijlstra
2020-05-20 12:28 ` Thomas Gleixner
2020-05-19 20:19 ` [PATCH 3/8] srcu: Use local_lock() for per-CPU struct srcu_data access Sebastian Andrzej Siewior
2020-05-20 10:24 ` Peter Zijlstra
2020-05-20 12:06 ` Sebastian Andrzej Siewior
2020-05-20 13:27 ` Peter Zijlstra
2020-05-20 17:42 ` Joel Fernandes
2020-05-20 18:28 ` Sebastian Andrzej Siewior
2020-05-20 18:35 ` Peter Zijlstra
2020-05-20 18:44 ` Joel Fernandes
2020-05-20 18:50 ` Uladzislau Rezki
2020-05-20 18:59 ` Joel Fernandes
2020-05-20 18:43 ` Paul E. McKenney
2020-05-22 15:12 ` Sebastian Andrzej Siewior
2020-05-22 17:39 ` Paul E. McKenney
2020-05-23 15:08 ` Sebastian Andrzej Siewior
2020-05-23 16:59 ` Paul E. McKenney
2020-05-24 19:03 ` Sebastian Andrzej Siewior
2020-05-25 3:27 ` Paul E. McKenney
2020-05-26 13:41 ` [PATCH] srcu: Avoid local_irq_save() before acquiring spinlock_t Sebastian Andrzej Siewior
2020-05-26 16:16 ` Paul E. McKenney
2020-05-26 16:31 ` Sebastian Andrzej Siewior
2020-05-19 20:19 ` [PATCH 4/8] mm/swap: Use local_lock for protection Sebastian Andrzej Siewior
2020-05-19 23:58 ` Andrew Morton
2020-05-20 2:17 ` Matthew Wilcox
2020-05-20 10:53 ` Peter Zijlstra
2020-05-19 20:19 ` [PATCH 5/8] squashfs: make use of local lock in multi_cpu decompressor Sebastian Andrzej Siewior
2020-05-20 10:56 ` Peter Zijlstra
2020-05-19 20:19 ` [PATCH 6/8] connector/cn_proc: Protect send_msg() with a local lock Sebastian Andrzej Siewior
2020-05-20 11:03 ` Peter Zijlstra
2020-05-19 20:19 ` [PATCH 7/8] zram: Use local lock to protect per-CPU data Sebastian Andrzej Siewior
2020-05-20 11:07 ` Peter Zijlstra
2020-05-19 20:19 ` [PATCH 8/8] mm/zswap: " Sebastian Andrzej Siewior
2020-05-19 21:46 ` Song Bao Hua
2020-05-20 10:26 ` Sebastian Andrzej Siewior
2020-05-20 11:13 ` Song Bao Hua
2020-05-20 11:57 ` Sebastian Andrzej Siewior [this message]
2020-05-20 12:01 ` Song Bao Hua
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