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charset=UTF-8 To: , , , , , , , , , References: <20260701090553.62691-1-lizhe.67@bytedance.com> X-Stat-Signature: i76c9xpmx6gp4sgzdtgfxm9idup6kygi X-Rspam-User: X-Rspamd-Queue-Id: CB2811C0002 X-Rspamd-Server: rspam02 X-HE-Tag: 1782896860-809387 X-HE-Meta: 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 yd2UWMS8 PtUXKltG0C1a6pKG6Sk0pKCrxOhzRCL9nieHDD1Yd82WHw/mFBIucwdKE4cl9smJSQOlvJZfRNuTuyS0kTo8Ekl5qoKRP3Qn3bVidsYnGP3c6tKrpBnamFShPSFR7ROGttAFNC3eKK0Wnmn2e+BsgUIrhDgBVM3iXMBUut/VmWyEytozVwVRTROq5tS0dTRBFSlMXWESTnhd2B5cpSupLqi0la55Ttg1giAqqueOOTUv0ESm6OleLuWgPQalEha+GB/EG++QwzWD3rRsFLCYxK7LtUSnuj/kWlW5AxnH2998JR8YaB+GkwCO5MZxQ17avmOtmFrzN0tlcRtU= 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_resets_refcount(), 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 | 57 ++++++++++++++++++++++++++++++++++------------------ 1 file changed, 38 insertions(+), 19 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index 95808ab5cfdb..4c7fad440c2a 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1005,11 +1005,38 @@ 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 the free path for this pagemap type restores the page + * refcount to 1, so memmap_init_zone_device() can keep the count set by + * __init_single_page(). Otherwise initialize the refcount to 0 and leave + * it to the allocator or pgmap callbacks to raise it when the page is + * handed out again. + */ +static inline bool pagemap_resets_refcount(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 false; + case MEMORY_DEVICE_GENERIC: + return true; + default: + WARN_ONCE(1, "Unknown memory type!"); + return true; + } +} + +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 +1055,15 @@ 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_resets_refcount(pgmap)) set_page_count(page, 0); - break; - - case MEMORY_DEVICE_GENERIC: - break; - } } /* @@ -1090,7 +1109,7 @@ 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 +1145,7 @@ 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