From: Yosry Ahmed <yosryahmed@google.com>
To: Chris Li <chrisl@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Nhat Pham <nphamcs@gmail.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Chengming Zhou <zhouchengming@bytedance.com>,
Barry Song <v-songbaohua@oppo.com>
Subject: Re: [PATCH v7] zswap: replace RB tree with xarray
Date: Wed, 20 Mar 2024 19:46:38 +0000 [thread overview]
Message-ID: <Zfs9HjKzKlw6qGjb@google.com> (raw)
In-Reply-To: <CANeU7Q=AXzG05BPcKPJvMDzmc8QK4UDKz+zaLQAx=RCrcsBkVA@mail.gmail.com>
On Wed, Mar 20, 2024 at 12:41:48PM -0700, Chris Li wrote:
> On Wed, Mar 20, 2024 at 12:34 PM Yosry Ahmed <yosryahmed@google.com> wrote:
> > > you can expect it to be coherent.
> >
> > Fair enough, but don't we still need a barrier there? Couldn't some
> > initializations still be reorder after zswap_lru_add()?
>
> I am under the impression that the lru list handling function already
> handles the barrier. If an explicit barrier is needed, wouldn't all
> other lru callers have barriers sprinkling all over the place?
list_lru_add() holds a lock, which implies a compiler barrier. I was
wondering if we need smp_wmb() to prevent other CPUs from observing a
partially initialized entry during writeback.
I am not sure if the list lru makes such assumptions about the need for
barriers.
next prev parent reply other threads:[~2024-03-20 19:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-20 5:52 Chris Li
2024-03-20 6:13 ` Yosry Ahmed
2024-03-20 6:34 ` Chris Li
2024-03-20 7:24 ` Yosry Ahmed
2024-03-20 10:08 ` Johannes Weiner
2024-03-20 18:34 ` Chris Li
2024-03-20 19:11 ` Yosry Ahmed
2024-03-20 19:25 ` Johannes Weiner
2024-03-20 19:34 ` Yosry Ahmed
2024-03-20 19:41 ` Chris Li
2024-03-20 19:46 ` Yosry Ahmed [this message]
2024-03-20 20:03 ` Johannes Weiner
2024-03-20 20:12 ` Yosry Ahmed
2024-03-20 10:14 ` Johannes Weiner
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