From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@kernel.org>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Muchun Song <muchun.song@linux.dev>,
Lorenzo Stoakes <ljs@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Nico Pache <nico.pache@linux.dev>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>,
Lance Yang <lance.yang@linux.dev>,
Usama Arif <usama.arif@linux.dev>,
Gregory Price <gourry@gourry.net>,
Ying Huang <ying.huang@linux.alibaba.com>,
Alistair Popple <apopple@nvidia.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Qi Zheng <qi.zheng@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Kairui Song <kasong@tencent.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Minchan Kim <minchan@kernel.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: Re: [PATCH v3 01/14] mm/zsmalloc: replace PG_private with pointer comparison
Date: Tue, 8 Sep 2026 13:11:16 +0900 [thread overview]
Message-ID: <ap-Kx9qjJX2ElrSw@google.com> (raw)
In-Reply-To: <20260907-remove-pg_private-v3-1-6ae22f9d9272@nvidia.com>
On (26/09/07 22:56), Zi Yan wrote:
> zsmalloc uses PG_private to indicate first zpdesc in a zspage chain. It is
> equivalent to check zpdesc == zspage->first_zpdesc. Replace
> is_first_zpdesc() with zpdesc == zspage->first_zpdesc in obj_allocated().
>
> For get_first_zpdesc(), first_zpdesc is from zspage->first_zpdesc, so
> replace is_first_zpdesc() with first_zpdesc->zspage == zspage, the second
> requirement of a zspage chain, where all zpdescs point to the same zspage.
>
> is_first_zpdesc(), is only used in VM_BUG_ON_PAGE(), so performance impact
> should be negligible. While at it, change VM_BUG_ON() to
> VM_WARN_ON_ONCE_PAGE().
>
> It prepares for a future commit that remove PG_private.
>
> No functional change intended.
>
> Assisted-by: Claude:claude-opus-4-8
> Assisted-by: Codex:gpt-5
> To: Minchan Kim <minchan@kernel.org>
> To: Sergey Senozhatsky <senozhatsky@chromium.org>
> To: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
next prev parent reply other threads:[~2026-09-08 4:11 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-08 2:56 [PATCH v3 00/14] Remove PG_private by using page/folio->private checks instead Zi Yan
2026-09-08 2:56 ` [f2fs-dev] " Zi Yan via Linux-f2fs-devel
2026-09-08 2:56 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 01/14] mm/zsmalloc: replace PG_private with pointer comparison Zi Yan
2026-09-08 4:11 ` Sergey Senozhatsky [this message]
2026-09-08 15:07 ` David Hildenbrand (Arm)
2026-09-08 15:21 ` Zi Yan
2026-09-09 14:07 ` David Hildenbrand (Arm)
2026-09-08 2:56 ` [PATCH v3 02/14] perf/ring_buffer: stop using PG_private as AUX page high-order marker Zi Yan
2026-09-08 3:07 ` sashiko-bot
2026-09-08 15:09 ` David Hildenbrand (Arm)
2026-09-08 2:56 ` [PATCH v3 03/14] xen/grant-table: stop setting PG_private on pages for grant mapping Zi Yan
2026-09-08 15:16 ` David Hildenbrand (Arm)
2026-09-08 15:44 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 04/14] fscrypt: stop setting PG_private on bounce page Zi Yan
2026-09-08 15:16 ` David Hildenbrand (Arm)
2026-09-08 2:56 ` [PATCH v3 05/14] mm/hugetlb: use direct assignment instead of folio_change_private() Zi Yan
2026-09-08 15:26 ` David Hildenbrand (Arm)
2026-09-08 15:28 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 06/14] f2fs: stop using PG_private Zi Yan
2026-09-08 2:56 ` [f2fs-dev] " Zi Yan via Linux-f2fs-devel
2026-09-08 15:47 ` David Hildenbrand (Arm) via Linux-f2fs-devel
2026-09-08 15:47 ` David Hildenbrand (Arm)
2026-09-08 18:20 ` [f2fs-dev] " Tal Zussman
2026-09-08 18:20 ` Tal Zussman
2026-09-09 12:48 ` [f2fs-dev] " David Hildenbrand (Arm) via Linux-f2fs-devel
2026-09-09 12:48 ` David Hildenbrand (Arm)
2026-09-09 17:47 ` Tal Zussman
2026-09-09 17:47 ` [f2fs-dev] " Tal Zussman
2026-09-10 7:35 ` David Hildenbrand (Arm)
2026-09-10 7:35 ` [f2fs-dev] " David Hildenbrand (Arm) via Linux-f2fs-devel
2026-09-10 12:21 ` Zi Yan
2026-09-10 12:21 ` [f2fs-dev] " Zi Yan via Linux-f2fs-devel
2026-09-10 21:11 ` Zi Yan
2026-09-10 21:11 ` [f2fs-dev] " Zi Yan via Linux-f2fs-devel
2026-09-13 20:11 ` Tal Zussman
2026-09-13 20:11 ` [f2fs-dev] " Tal Zussman
2026-09-10 2:41 ` Chao Yu
2026-09-10 2:41 ` [f2fs-dev] " Chao Yu via Linux-f2fs-devel
2026-09-10 7:34 ` David Hildenbrand (Arm) via Linux-f2fs-devel
2026-09-10 7:34 ` David Hildenbrand (Arm)
2026-09-10 8:43 ` [f2fs-dev] " Chao Yu via Linux-f2fs-devel
2026-09-10 8:43 ` Chao Yu
2026-09-10 9:15 ` David Hildenbrand (Arm)
2026-09-10 9:15 ` [f2fs-dev] " David Hildenbrand (Arm) via Linux-f2fs-devel
2026-09-10 14:15 ` Chao Yu
2026-09-10 14:15 ` [f2fs-dev] " Chao Yu via Linux-f2fs-devel
2026-09-08 2:56 ` [PATCH v3 07/14] erofs: mm/pagemap: add readahead_folio_last() to avoid folio->private Zi Yan
2026-09-08 16:04 ` David Hildenbrand (Arm)
2026-09-08 17:05 ` Zi Yan
2026-09-09 14:10 ` David Hildenbrand (Arm)
2026-09-08 2:56 ` [PATCH v3 08/14] erofs: use folio_attach/detach_private() instead of direct assignment Zi Yan
2026-09-08 16:13 ` David Hildenbrand (Arm)
2026-09-08 17:19 ` Zi Yan
2026-09-09 13:27 ` David Hildenbrand (Arm)
2026-09-10 2:06 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 09/14] mm/page-flags: check page/folio->private instead of PG_private Zi Yan
2026-09-08 16:56 ` David Hildenbrand (Arm)
2026-09-10 2:08 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 10/14] mm/page-flags: introduce folio_test_fs_private() Zi Yan
2026-09-08 16:59 ` David Hildenbrand (Arm)
2026-09-08 17:22 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 11/14] treewide: remove folio_set/clear_private() Zi Yan
2026-09-08 17:01 ` David Hildenbrand (Arm)
2026-09-08 17:22 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 12/14] treewide: replace PagePrivate() with page_private() Zi Yan
2026-09-09 14:18 ` David Hildenbrand (Arm)
2026-09-09 14:23 ` David Hildenbrand (Arm)
2026-09-10 2:09 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 13/14] treewide: adjust comments on PagePrivate and PG_private Zi Yan
2026-09-08 2:56 ` Zi Yan
2026-09-09 14:20 ` David Hildenbrand (Arm)
2026-09-09 14:20 ` David Hildenbrand (Arm)
2026-09-09 14:27 ` David Hildenbrand (Arm)
2026-09-09 14:27 ` David Hildenbrand (Arm)
2026-09-10 2:12 ` Zi Yan
2026-09-10 2:12 ` Zi Yan
2026-09-08 2:56 ` [PATCH v3 14/14] mm/page-flags: remove PG_private Zi Yan
2026-09-09 14:31 ` David Hildenbrand (Arm)
2026-09-09 14:48 ` Zi Yan
2026-09-09 14:50 ` David Hildenbrand (Arm)
2026-09-09 14:51 ` Zi Yan
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