Received-SPF: pass (google.com: domain of linux-kernel+bounces-29605-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Precedence: bulk
MIME-Version: 1.0
References: <20240117-b4-zswap-lock-optimize-v1-0-23f6effe5775@bytedance.com>
 <CAJD7tkY7Xvjg37EEw2M=uRknphY0pf3ZVpyX2s2QyiJ=Axhihw@mail.gmail.com>
 <CAF8kJuP4o3Ebg-aYKF9=ftbdu97RnkXnYL-8RuVjYAeXd+ng3A@mail.gmail.com>
 <CAJD7tkYfo6mNjHQJt4yfVuh55tMyVMRnbeq5ki42tYHBEgP_eA@mail.gmail.com>
 <CAF8kJuO=3-DMV-rXBZE-hVUXzQcV5B1HPFGzpzL99_5WggqF9Q@mail.gmail.com> <CAJD7tkadpOmERPzUyYUX=8=POan=Pm1zSae81zyRhYLXDHo_7g@mail.gmail.com>
In-Reply-To: <CAJD7tkadpOmERPzUyYUX=8=POan=Pm1zSae81zyRhYLXDHo_7g@mail.gmail.com>
From: Chris Li <chrisl@kernel.org>
Date: Wed, 17 Jan 2024 17:03:27 -0800
Message-ID: <CAF8kJuMRWDuY5hbAzbA9bQ5=4RztvD3tLB-W+6besGBk11+pPQ@mail.gmail.com>
Subject: Re: [PATCH 0/2] mm/zswap: optimize the scalability of zswap rb-tree
To: Yosry Ahmed <yosryahmed@google.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>, Andrew Morton <akpm@linux-foundation.org>, 
	linux-kernel@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>, linux-mm@kvack.org, 
	Nhat Pham <nphamcs@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Hi Yosry,

On Wed, Jan 17, 2024 at 4:35=E2=80=AFPM Yosry Ahmed <yosryahmed@google.com>=
 wrote:
> Hmm I don't understand. What's the point of keeping the rbtree if we
> have the xarray? Doesn't it end up being more expensive and bug-prone
> to maintain both trees?

Patch 2/2 remove the rb tree code. Just keeping the tree spinlock.

>
> When you say "eventual goal", do you mean what the patch would morph
> into in later versions (as in v1 is just a proof of concept without
> removing the rbtree), or follow up patches?

V1 will remove the rb tree, but does not merge the rb tree lock with
the xarray lock.

Hi Nhat,

> Hmmm why? Is there a reason to keep the rb tree around?

No, not at all.


Chris