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AJvYcCU+nX+hmCjtP360vUwk39ndoM93aCIuk1Ijh12pU+KDJuSlZoYitY0Mw3GBRTDc2SRn77n7QnkT6csztlo=@vger.kernel.org X-Gm-Message-State: AOJu0YxPP9F2ZtFJj948iJjf1W4YI5l8qnz2Fpe5L31hd9Ryod3uWyHi wYxw0m//OITgb5RPVE5+TD3wXgSnljcP3cuuh/byMrg+kfynR0OfLjPME73M2FVsRU45jvBpIOd UZDc50yY4dB4AqQ== X-Google-Smtp-Source: AGHT+IENVvEwJMRWsbG8t8DKamJf+m7Kq67/5OJ3seeLWXwPuYI2slv5FtZcLQnrkEJ74Z2KnexNe0JoOpqTUg== X-Received: from pjod1.prod.google.com ([2002:a17:90a:8d81:b0:33b:b692:47b0]) (user=jiaqiyan job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:1a8a:b0:341:69e3:785a with SMTP id 98e67ed59e1d1-343f9fdf8efmr10663049a91.16.1763257645886; Sat, 15 Nov 2025 17:47:25 -0800 (PST) Date: Sun, 16 Nov 2025 01:47:20 +0000 In-Reply-To: <20251116014721.1561456-1-jiaqiyan@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251116014721.1561456-1-jiaqiyan@google.com> X-Mailer: git-send-email 2.52.0.rc1.455.g30608eb744-goog Message-ID: <20251116014721.1561456-2-jiaqiyan@google.com> Subject: [PATCH v1 1/2] mm/huge_memory: introduce uniform_split_unmapped_folio_to_zero_order From: Jiaqi Yan To: nao.horiguchi@gmail.com, linmiaohe@huawei.com, ziy@nvidia.com Cc: david@redhat.com, lorenzo.stoakes@oracle.com, william.roche@oracle.com, harry.yoo@oracle.com, tony.luck@intel.com, wangkefeng.wang@huawei.com, willy@infradead.org, jane.chu@oracle.com, akpm@linux-foundation.org, osalvador@suse.de, muchun.song@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jiaqi Yan Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When freeing a high-order folio that contains HWPoison pages, to ensure these HWPoison pages are not added to buddy allocator, we can first uniformly split a free and unmapped high-order folio to 0-order folios first, then only add non-HWPoison folios to buddy allocator and exclude HWPoison ones. Introduce uniform_split_unmapped_folio_to_zero_order, a wrapper to the existing __split_unmapped_folio. Caller can use it to uniformly split an unmapped high-order folio into 0-order folios. No functional change. It will be used in a subsequent commit. Signed-off-by: Jiaqi Yan --- include/linux/huge_mm.h | 6 ++++++ mm/huge_memory.c | 8 ++++++++ 2 files changed, 14 insertions(+) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 71ac78b9f834f..ef6a84973e157 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -365,6 +365,7 @@ unsigned long thp_get_unmapped_area_vmflags(struct file= *filp, unsigned long add vm_flags_t vm_flags); =20 bool can_split_folio(struct folio *folio, int caller_pins, int *pextra_pin= s); +int uniform_split_unmapped_folio_to_zero_order(struct folio *folio); int split_huge_page_to_list_to_order(struct page *page, struct list_head *= list, unsigned int new_order); int min_order_for_split(struct folio *folio); @@ -569,6 +570,11 @@ can_split_folio(struct folio *folio, int caller_pins, = int *pextra_pins) { return false; } +static inline int uniform_split_unmapped_folio_to_zero_order(struct folio = *folio) +{ + VM_WARN_ON_ONCE_PAGE(1, page); + return -EINVAL; +} static inline int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, unsigned int new_order) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 323654fb4f8cf..c7b6c1c75a18e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3515,6 +3515,14 @@ static int __split_unmapped_folio(struct folio *foli= o, int new_order, return ret; } =20 +int uniform_split_unmapped_folio_to_zero_order(struct folio *folio) +{ + return __split_unmapped_folio(folio, /*new_order=3D*/0, + /*split_at=3D*/&folio->page, + /*xas=3D*/NULL, /*mapping=3D*/NULL, + /*uniform_split=3D*/true); +} + bool non_uniform_split_supported(struct folio *folio, unsigned int new_ord= er, bool warns) { --=20 2.52.0.rc1.455.g30608eb744-goog