From: David Hildenbrand <david@redhat.com>
To: SeongJae Park <sj@kernel.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chengming Zhou <chengming.zhou@linux.dev>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Michal Hocko <mhocko@suse.com>, Mike Rapoport <rppt@kernel.org>,
Nhat Pham <nphamcs@gmail.com>,
Suren Baghdasaryan <surenb@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
Yosry Ahmed <yosry.ahmed@linux.dev>,
kernel-team@meta.com, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Takero Funaki <flintglass@gmail.com>
Subject: Re: [RFC PATCH v2] mm/zswap: store <PAGE_SIZE compression failed page as-is
Date: Tue, 5 Aug 2025 12:47:36 +0200 [thread overview]
Message-ID: <761a2899-6fd9-4bfe-aeaf-23bce0baa0f1@redhat.com> (raw)
In-Reply-To: <20250805002954.1496-1-sj@kernel.org>
On 05.08.25 02:29, SeongJae Park wrote:
> When zswap writeback is enabled and it fails compressing a given page,
> the page is swapped out to the backing swap device. This behavior
> breaks the zswap's writeback LRU order, and hence users can experience
> unexpected latency spikes. If the page is compressed without failure,
> but results in a size of PAGE_SIZE, the LRU order is kept, but the
> decompression overhead for loading the page back on the later access is
> unnecessary.
>
> Keep the LRU order and optimize unnecessary decompression overheads in
> the cases, by storing the original content in zpool as-is.
Does this have any effect on the movability of the given page? IOW, does
page migration etc. still work when we store an ordinary page of an
shmem/anon folio here?
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2025-08-05 10:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-05 0:29 SeongJae Park
2025-08-05 10:47 ` David Hildenbrand [this message]
2025-08-05 16:56 ` Nhat Pham
2025-08-06 20:14 ` David Hildenbrand
2025-08-06 21:28 ` SeongJae Park
2025-08-06 23:48 ` Shakeel Butt
2025-08-07 5:55 ` David Hildenbrand
2025-08-07 16:50 ` SeongJae Park
2025-08-05 18:43 ` SeongJae Park
2025-08-05 18:25 ` Nhat Pham
2025-08-05 18:31 ` Nhat Pham
2025-08-05 18:51 ` SeongJae Park
2025-08-06 16:32 ` Johannes Weiner
2025-08-06 16:56 ` SeongJae Park
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