Re: [PATCH v3 1/8] mm: Remove special swap entry functions
From: Christoph Hellwig <hch@infradead.org>
Date: 2021-02-26 16:00:46
Also in:
linux-mm, lkml, nouveau
- struct page *page = migration_entry_to_page(entry); + struct page *page = pfn_to_page(swp_offset(entry));
I wonder if keeping a single special_entry_to_page() helper would still me a useful. But I'm not entirely sure. There are also two more open coded copies of this in the THP migration code.
-#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
-#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));})
+#define free_swap_and_cache(e) is_special_entry(e)
+#define swapcache_prepare(e) is_special_entry(e)Staring at this I'm really, really confused at what this is doing. Looking a little closer these are the !CONFIG_SWAP stubs, but it could probably use a comment or two.
quoted hunk ↗ jump to hunk
} else if (is_migration_entry(entry)) { - page = migration_entry_to_page(entry); + page = pfn_to_page(swp_offset(entry)); rss[mm_counter(page)]++;@@ -737,7 +737,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, set_pte_at(src_mm, addr, src_pte, pte); } } else if (is_device_private_entry(entry)) { - page = device_private_entry_to_page(entry); + page = pfn_to_page(swp_offset(entry)); /* * Update rss count even for unaddressable pages, as@@ -1274,7 +1274,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, entry = pte_to_swp_entry(ptent); if (is_device_private_entry(entry)) { - struct page *page = device_private_entry_to_page(entry); + struct page *page = pfn_to_page(swp_offset(entry)); if (unlikely(details && details->check_mapping)) { /*@@ -1303,7 +1303,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, else if (is_migration_entry(entry)) { struct page *page; - page = migration_entry_to_page(entry); + page = pfn_to_page(swp_offset(entry)); rss[mm_counter(page)]--; } if (unlikely(!free_swap_and_cache(entry)))@@ -3271,7 +3271,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) migration_entry_wait(vma->vm_mm, vmf->pmd, vmf->address); } else if (is_device_private_entry(entry)) { - vmf->page = device_private_entry_to_page(entry); + vmf->page = pfn_to_page(swp_offset(entry)); ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); } else if (is_hwpoison_entry(entry)) { ret = VM_FAULT_HWPOISON;diff --git a/mm/migrate.c b/mm/migrate.c index 20ca887ea769..72adcc3d8f5b 100644 --- a/mm/migrate.c +++ b/mm/migrate.c@@ -321,7 +321,7 @@ void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, if (!is_migration_entry(entry)) goto out; - page = migration_entry_to_page(entry); + page = pfn_to_page(swp_offset(entry)); /* * Once page cache replacement of page migration started, page_count@@ -361,7 +361,7 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd) ptl = pmd_lock(mm, pmd); if (!is_pmd_migration_entry(*pmd)) goto unlock; - page = migration_entry_to_page(pmd_to_swp_entry(*pmd)); + page = pfn_to_page(swp_offset(pmd_to_swp_entry(*pmd))); if (!get_page_unless_zero(page)) goto unlock; spin_unlock(ptl);@@ -2437,7 +2437,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, if (!is_device_private_entry(entry)) goto next; - page = device_private_entry_to_page(entry); + page = pfn_to_page(swp_offset(entry)); if (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_PRIVATE) || page->pgmap->owner != migrate->pgmap_owner)diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 86e3a3688d59..34230d08556a 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c@@ -96,7 +96,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw) if (!is_migration_entry(entry)) return false; - pfn = migration_entry_to_pfn(entry); + pfn = swp_offset(entry); } else if (is_swap_pte(*pvmw->pte)) { swp_entry_t entry;@@ -105,7 +105,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw) if (!is_device_private_entry(entry)) return false; - pfn = device_private_entry_to_pfn(entry); + pfn = swp_offset(entry); } else { if (!pte_present(*pvmw->pte)) return false;@@ -200,7 +200,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) if (is_migration_entry(pmd_to_swp_entry(*pvmw->pmd))) { swp_entry_t entry = pmd_to_swp_entry(*pvmw->pmd); - if (migration_entry_to_page(entry) != page) + if (pfn_to_page(swp_offset(entry)) != page) return not_found(pvmw); return true; }-- 2.20.1
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