On Saturday, 27 February 2021 2:59:09 AM AEDT Christoph Hellwig wrote:
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.
I think it might be if only to clearly document where these entries are used. Will add it for the next version to see what it looks like.
-#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.
Will do, thanks.
- Alistair
} 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)]--;@@ -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);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);@@ -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);@@ -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; }---end quoted text---