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charset=UTF-8 From: "Li Zhe" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Date: Mon, 10 Aug 2026 20:20:51 +0800 X-Original-From: Li Zhe In-Reply-To: <20260810122057.30447-1-lizhe.67@bytedance.com> X-Lms-Return-Path: To: , , , , , , , , , , , Cc: , , , , , Subject: [PATCH v10 2/8] mm: factor zone-device page init helpers out of __init_zone_device_page X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 40B282000D X-Stat-Signature: ic9fz3qun3wkdtdad78uein9kbqbh3mi X-HE-Tag: 1786364555-326507 X-HE-Meta: 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 oF8G01Ip JDEsbZY9NQsxxkZyIYmmQNbrVVsSFmhDS0YeCmusBfveed2nj/pl1gESDtz8UV1BM5PUUx50FA5MVP70w1AhVCtU2FeHdv8pd8u9u3oMyDMFMIOba2lqwxJkw0JpoorWJGc7nRu9GECzDhfc9/6/tPKBDpgU/pyHXgAsHVuMBHeZxILrxMkoYOYJqGHXXIIkE3dS0gw8gTx1TdWt0eOOG+QtXGVzM6EMcI+ojRgMJS/1alo8FF/hdbLu7AjQCjiqaExIkbR9gZWBv+WlUoSUAANujqxddIm7OSb5ouGUUImK50USlgq66fjA0OnlLuN1hYrnusaruPhjFm8DciKFRJ0tczCxGWEQyT9X9tj2GfciSsMl5dGnFm4LqhMUqjcQ5sOVQnWSrZ4+xALLFPdCclcrPmfy1iqJvKZ8NtHb7qhVDcHlZvACgI8TOYw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: memmap_init_zone_device() currently mixes refcount policy and core ZONE_DEVICE page setup in a single helper. Factor the refcount-reset predicate into pagemap_requires_refcount_reset(), move the common page initialization into __zone_device_page_init(), and wrap the existing slow path in zone_device_page_init_slow(). This keeps the slow-path behaviour unchanged and gives later patches reusable helper boundaries. No functional change intended. Signed-off-by: Li Zhe Reviewed-by: Mike Rapoport (Microsoft) --- mm/mm_init.c | 56 ++++++++++++++++++++++++++++++++++------------------ 1 file changed, 37 insertions(+), 19 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index 95808ab5cfdb..a70acb7431a6 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1005,11 +1005,37 @@ static void __init memmap_init(void) } #ifdef CONFIG_ZONE_DEVICE -static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, +/* + * Return true when memmap_init_zone_device() must initialize the page + * refcount to 0. 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. + */ +static inline bool pagemap_requires_refcount_reset(const struct dev_pagemap *pgmap) +{ + /* + * 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: + case MEMORY_DEVICE_PRIVATE: + case MEMORY_DEVICE_COHERENT: + case MEMORY_DEVICE_PCI_P2PDMA: + return true; + case MEMORY_DEVICE_GENERIC: + return false; + } + + return false; +} + +static void __ref __zone_device_page_init(struct page *page, unsigned long pfn, unsigned long zone_idx, int nid, struct dev_pagemap *pgmap) { - __init_single_page(page, pfn, zone_idx, nid); /* @@ -1028,23 +1054,15 @@ static void __ref __init_zone_device_page(struct page *page, unsigned long pfn, */ page_folio(page)->pgmap = pgmap; page->zone_device_data = NULL; +} - /* - * 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: - case MEMORY_DEVICE_PRIVATE: - case MEMORY_DEVICE_COHERENT: - case MEMORY_DEVICE_PCI_P2PDMA: +static void __ref zone_device_page_init_slow(struct page *page, + unsigned long pfn, unsigned long zone_idx, int nid, + struct dev_pagemap *pgmap) +{ + __zone_device_page_init(page, pfn, zone_idx, nid, pgmap); + if (pagemap_requires_refcount_reset(pgmap)) set_page_count(page, 0); - break; - - case MEMORY_DEVICE_GENERIC: - break; - } } /* @@ -1090,7 +1108,7 @@ static void __ref memmap_init_compound(struct page *head, for (pfn = head_pfn + 1; pfn < end_pfn; pfn++) { struct page *page = pfn_to_page(pfn); - __init_zone_device_page(page, pfn, zone_idx, nid, pgmap); + zone_device_page_init_slow(page, pfn, zone_idx, nid, pgmap); prep_compound_tail(page, head, order); set_page_count(page, 0); } @@ -1126,7 +1144,7 @@ void __ref memmap_init_zone_device(struct zone *zone, for (pfn = start_pfn; pfn < end_pfn; pfn += pfns_per_compound) { struct page *page = pfn_to_page(pfn); - __init_zone_device_page(page, pfn, zone_idx, nid, pgmap); + zone_device_page_init_slow(page, pfn, zone_idx, nid, pgmap); if (IS_ALIGNED(pfn, PAGES_PER_SECTION)) cond_resched(); -- 2.20.1