From: Yosry Ahmed <yosryahmed@google.com>
To: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Nhat Pham <nphamcs@gmail.com>, Chris Li <chriscli@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Seth Jennings <sjenning@redhat.com>,
Dan Streetman <ddstreet@ieee.org>,
Vitaly Wool <vitaly.wool@konsulko.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/5] mm/zswap: change dstmem size to one page
Date: Wed, 13 Dec 2023 15:34:17 -0800 [thread overview]
Message-ID: <CAJD7tkZJRgf+502QU_ECVPey0w-5vw_e6HSL+Ay7unetq5gL0A@mail.gmail.com> (raw)
In-Reply-To: <20231213-zswap-dstmem-v1-2-896763369d04@bytedance.com>
On Tue, Dec 12, 2023 at 8:18 PM Chengming Zhou
<zhouchengming@bytedance.com> wrote:
>
> Change the dstmem size from 2 * PAGE_SIZE to only one page since
> we only need at most one page when compress, and the "dlen" is also
> PAGE_SIZE in acomp_request_set_params(). If the output size > PAGE_SIZE
> we don't wanna store the output in zswap anyway.
>
> So change it to one page, and delete the stale comment.
I couldn't find the history of why we needed 2 * PAGE_SIZE, it would
be nice if someone has the context, perhaps one of the maintainers.
One potential reason is that we used to store a zswap header
containing the swap entry in the compressed page for writeback
purposes, but we don't do that anymore. Maybe we wanted to be able to
handle the case where an incompressible page would exceed PAGE_SIZE
because of that?
next prev parent reply other threads:[~2023-12-13 23:34 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-13 4:17 [PATCH 0/5] mm/zswap: dstmem reuse optimizations and cleanups Chengming Zhou
2023-12-13 4:17 ` [PATCH 1/5] mm/zswap: reuse dstmem when decompress Chengming Zhou
2023-12-13 23:24 ` Yosry Ahmed
2023-12-14 13:29 ` Chengming Zhou
2023-12-14 13:32 ` Yosry Ahmed
2023-12-14 14:42 ` Chengming Zhou
2023-12-14 18:24 ` Yosry Ahmed
2023-12-18 8:06 ` Chengming Zhou
2023-12-14 17:59 ` Chris Li
2023-12-14 18:26 ` Yosry Ahmed
2023-12-14 22:02 ` Chris Li
2023-12-14 20:33 ` Nhat Pham
2023-12-13 4:17 ` [PATCH 2/5] mm/zswap: change dstmem size to one page Chengming Zhou
2023-12-13 23:34 ` Yosry Ahmed [this message]
2023-12-14 0:18 ` Nhat Pham
2023-12-14 13:33 ` Chengming Zhou
2023-12-14 13:37 ` Yosry Ahmed
2023-12-14 13:57 ` Chengming Zhou
2023-12-14 15:03 ` Chengming Zhou
2023-12-14 18:34 ` Yosry Ahmed
2023-12-14 18:30 ` Yosry Ahmed
2023-12-14 20:29 ` Nhat Pham
2023-12-13 4:18 ` [PATCH 3/5] mm/zswap: refactor out __zswap_load() Chengming Zhou
2023-12-13 23:37 ` Yosry Ahmed
2023-12-14 0:52 ` Yosry Ahmed
2023-12-14 14:45 ` Chengming Zhou
2023-12-18 8:15 ` Chengming Zhou
2023-12-18 9:38 ` Yosry Ahmed
2023-12-13 4:18 ` [PATCH 4/5] mm/zswap: cleanup zswap_load() Chengming Zhou
2023-12-14 0:56 ` Yosry Ahmed
2023-12-13 4:18 ` [PATCH 5/5] mm/zswap: cleanup zswap_reclaim_entry() Chengming Zhou
2023-12-13 23:27 ` Nhat Pham
2023-12-14 1:02 ` Yosry Ahmed
2023-12-14 22:23 ` Andrew Morton
2023-12-14 22:41 ` Yosry Ahmed
2023-12-18 14:03 ` Johannes Weiner
2023-12-18 14:39 ` Yosry Ahmed
2023-12-18 14:58 ` Johannes Weiner
2023-12-18 20:52 ` Yosry Ahmed
2023-12-19 12:16 ` Chengming Zhou
2023-12-20 4:30 ` Johannes Weiner
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