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 12:26:34 +0200 [thread overview]
Message-ID: <20200520102634.pin4mzyytmfqtuo2@linutronix.de> (raw)
In-Reply-To: <B926444035E5E2439431908E3842AFD24AFEC5@DGGEMI525-MBS.china.huawei.com>
On 2020-05-19 21:46:06 [+0000], Song Bao Hua wrote:
> Hi Luis,
> In the below patch, in order to use the acomp APIs to leverage the power of hardware compressors. I have moved to mutex:
> https://marc.info/?l=linux-crypto-vger&m=158941285830302&w=2
> https://marc.info/?l=linux-crypto-vger&m=158941287930311&w=2
>
> so once we get some progress on that one, I guess we don't need a special patch for RT any more.
If you convert this way from the current concept then we could drop it
from the series.
The second patch shows the following hunk:
|@@ -1075,11 +1124,20 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
|
| /* compress */
| dst = get_cpu_var(zswap_dstmem);
| acomp_ctx = *this_cpu_ptr(entry->pool->acomp_ctx);
| put_cpu_var(zswap_dstmem);
So here you get per-CPU version of `dst' and `acomp_ctx' and then allow
preemption again.
| mutex_lock(&acomp_ctx->mutex);
|
| src = kmap(page);
| sg_init_one(&input, src, PAGE_SIZE);
| /* zswap_dstmem is of size (PAGE_SIZE * 2). Reflect same in sg_list */
| sg_init_one(&output, dst, PAGE_SIZE * 2);
and here you use `dst' and `acomp_ctx' after the preempt_disable() has
been dropped so I don't understand why you used get_cpu_var(). It is
either protected by the mutex and doesn't require get_cpu_var() or it
isn't (and should have additional protection).
| acomp_request_set_params(acomp_ctx->req, &input, &output, PAGE_SIZE, dlen);
| ret = crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acomp_ctx->wait);
| dlen = acomp_ctx->req->dlen;
| kunmap(page);
|
| if (ret) {
| ret = -EINVAL;
| goto put_dstmem;
|
Sebastian
next prev parent reply other threads:[~2020-05-20 10:26 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 [this message]
2020-05-20 11:13 ` Song Bao Hua
2020-05-20 11:57 ` Sebastian Andrzej Siewior
2020-05-20 12:01 ` Song Bao Hua
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