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charset=UTF-8 To: , , , , , , , , , , , Cc: , , , , , X-Original-From: Li Zhe X-Mailer: git-send-email 2.45.2 References: <20260727123429.5673-1-lizhe.67@bytedance.com> From: "Li Zhe" Content-Transfer-Encoding: 7bit X-Lms-Return-Path: Date: Mon, 27 Jul 2026 20:34:21 +0800 Mime-Version: 1.0 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 8A204180008 X-Rspam-User: X-Stat-Signature: r5wwjubapwcbedxkxag5wm17xqekhurj X-HE-Tag: 1785155727-888506 X-HE-Meta: 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 d6d+UJeH BYkTnJ55ZlJ9awOFSGhK4TOZAMdVtjbfT9R9oFdgKwOIqpElPX2UiJKZaNGEGPfI6Q8CzKRDGwnBl5q0uJBAg/e9aURjupK459Pb4Q8NzYOMSA+c4WTrZxWVnF/9sgGtrCWEPabLZ+GsPHYg08j6yPLbpmXTXS+7IxP7nual0d7MAbLVmrfwiwHjL+NWdR/64+mqSSkd6aIoeT7XBMuu/APmiIP5ujppxsi82pA6s++oJKxCXJl686fWy9H5ejiPrOMbGHx538an4ZAI4f7A+MgjJ3zynDPwPwHVGK2vJigKGoENGW5RNHF/uEMfjpmupO2JfTRnp4zucqni6GurLYkRqFqurSJoA2N/qhJaO3Nb7s5DCXu5xBmhx06ZEY1U+HAg+paXSzE7X7+UL/CDE3DliuxRQ0qT8fwgWL0SgcSCHvY14R3Ah2ZWmihqb2w3i7KWWGWoH7eMR9vOMhkuH+NdfIQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The comment in __init_zone_device_page() still uses the old MEMORY_TYPE_* names and implies that FS_DAX pages regain a refcount of 1 in the free path. That no longer matches the code. Update the comment to describe the current policy correctly: MEMORY_DEVICE_GENERIC pages regain a refcount of 1 in the free path, while the remaining ZONE_DEVICE types start from 0 here and raise the count again when the allocator or driver hands the page out. No functional change intended. Signed-off-by: Li Zhe Reviewed-by: David Hildenbrand (Arm) Reviewed-by: Alistair Popple Reviewed-by: Muchun Song --- mm/mm_init.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index 0f64909e8d20..95808ab5cfdb 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1030,13 +1030,9 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, page->zone_device_data = NULL; /* - * ZONE_DEVICE pages other than MEMORY_TYPE_GENERIC are released - * directly to the driver page allocator which will set the page count - * to 1 when allocating the page. - * - * MEMORY_TYPE_GENERIC and MEMORY_TYPE_FS_DAX pages automatically have - * their refcount reset to one whenever they are freed (ie. after - * their refcount drops to 0). + * MEMORY_DEVICE_GENERIC pages regain a refcount of 1 in the free + * path. The remaining ZONE_DEVICE types start from 0 here and raise + * the count again when the allocator or driver hands the page out. */ switch (pgmap->type) { case MEMORY_DEVICE_FS_DAX: -- 2.20.1