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 <[email protected]> Reviewed-by: Mike Rapoport (Microsoft) <[email protected]> --- 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
