From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Luka Bai <lukafocus@icloud.com>, linux-mm@kvack.org
Cc: Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <ljs@kernel.org>, Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Liam R. Howlett" <liam@infradead.org>,
Nico Pache <npache@redhat.com>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jann Horn <jannh@google.com>,
Arnd Bergmann <arnd@arndb.de>, Kairui Song <kasong@tencent.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, Luka Bai <lukabai@tencent.com>
Subject: Re: [PATCH 5/5] mm: support choosing to do THP COW for anonymous pmd entry.
Date: Fri, 1 May 2026 09:11:42 +0200 [thread overview]
Message-ID: <c580340a-48c3-4cfa-92bd-593a95d0090f@kernel.org> (raw)
In-Reply-To: <20260501-thp_cow-v1-5-005377483738@tencent.com>
> - /*
> - * See do_wp_page(): we can only reuse the folio exclusively if
> - * there are no additional references. Note that we always drain
> - * the LRU cache immediately after adding a THP.
> - */
> - if (folio_ref_count(folio) >
> - 1 + folio_test_swapcache(folio) * folio_nr_pages(folio))
> - goto unlock_fallback;
> if (folio_test_swapcache(folio))
I don't see why you would want to remove this check, really. Instead of
"fallback", you might want to try copying the PMD.
--
Cheers,
David
next prev parent reply other threads:[~2026-05-01 7:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-01 5:55 [PATCH 0/5] mm: Support selecting doing direct COW for anonymous pmd entry Luka Bai
2026-05-01 5:55 ` [PATCH 1/5] mm: add basic madvise helpers and branch for THP setup Luka Bai
2026-05-01 5:55 ` [PATCH 2/5] mm: add pmd level THP COW parameter in sysfs Luka Bai
2026-05-01 5:55 ` [PATCH 3/5] mm: add pmd level THP COW judgement helpers Luka Bai
2026-05-01 5:55 ` [PATCH 4/5] mm: enable map_anon_folio_pmd_nopf to handle unshare Luka Bai
2026-05-23 14:25 ` kernel test robot
2026-05-01 5:55 ` [PATCH 5/5] mm: support choosing to do THP COW for anonymous pmd entry Luka Bai
2026-05-01 7:11 ` David Hildenbrand (Arm) [this message]
2026-05-01 15:01 ` Luka Bai
2026-05-01 7:07 ` [PATCH 0/5] mm: Support selecting doing direct " David Hildenbrand (Arm)
2026-05-01 16:16 ` Luka Bai
2026-05-01 18:30 ` David Hildenbrand (Arm)
2026-05-02 5:06 ` Luka Bai
2026-05-03 7:03 ` [syzbot ci] " syzbot ci
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