diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/gup.c | 78 | ||||
| -rw-r--r-- | mm/hugetlb.c | 6 | ||||
| -rw-r--r-- | mm/page_alloc.c | 2 | ||||
| -rw-r--r-- | mm/rmap.c | 6 |
4 files changed, 84 insertions, 8 deletions
@@ -29,6 +29,22 @@ struct follow_page_context { unsigned int page_mask; }; +static void hpage_pincount_add(struct page *page, int refs) +{ + VM_BUG_ON_PAGE(!hpage_pincount_available(page), page); + VM_BUG_ON_PAGE(page != compound_head(page), page); + + atomic_add(refs, compound_pincount_ptr(page)); +} + +static void hpage_pincount_sub(struct page *page, int refs) +{ + VM_BUG_ON_PAGE(!hpage_pincount_available(page), page); + VM_BUG_ON_PAGE(page != compound_head(page), page); + + atomic_sub(refs, compound_pincount_ptr(page)); +} + /* * Return the compound head page with ref appropriately incremented, * or NULL if that failed. @@ -70,8 +86,25 @@ static __maybe_unused struct page *try_grab_compound_head(struct page *page, if (flags & FOLL_GET) return try_get_compound_head(page, refs); else if (flags & FOLL_PIN) { - refs *= GUP_PIN_COUNTING_BIAS; - return try_get_compound_head(page, refs); + /* + * When pinning a compound page of order > 1 (which is what + * hpage_pincount_available() checks for), use an exact count to + * track it, via hpage_pincount_add/_sub(). + * + * However, be sure to *also* increment the normal page refcount + * field at least once, so that the page really is pinned. + */ + if (!hpage_pincount_available(page)) + refs *= GUP_PIN_COUNTING_BIAS; + + page = try_get_compound_head(page, refs); + if (!page) + return NULL; + + if (hpage_pincount_available(page)) + hpage_pincount_add(page, refs); + + return page; } WARN_ON_ONCE(1); @@ -106,12 +139,25 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags) if (flags & FOLL_GET) return try_get_page(page); else if (flags & FOLL_PIN) { + int refs = 1; + page = compound_head(page); if (WARN_ON_ONCE(page_ref_count(page) <= 0)) return false; - page_ref_add(page, GUP_PIN_COUNTING_BIAS); + if (hpage_pincount_available(page)) + hpage_pincount_add(page, 1); + else + refs = GUP_PIN_COUNTING_BIAS; + + /* + * Similar to try_grab_compound_head(): even if using the + * hpage_pincount_add/_sub() routines, be sure to + * *also* increment the normal page refcount field at least + * once, so that the page really is pinned. + */ + page_ref_add(page, refs); } return true; @@ -120,12 +166,17 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags) #ifdef CONFIG_DEV_PAGEMAP_OPS static bool __unpin_devmap_managed_user_page(struct page *page) { - int count; + int count, refs = 1; if (!page_is_devmap_managed(page)) return false; - count = page_ref_sub_return(page, GUP_PIN_COUNTING_BIAS); + if (hpage_pincount_available(page)) + hpage_pincount_sub(page, 1); + else + refs = GUP_PIN_COUNTING_BIAS; + + count = page_ref_sub_return(page, refs); /* * devmap page refcounts are 1-based, rather than 0-based: if @@ -157,6 +208,8 @@ static bool __unpin_devmap_managed_user_page(struct page *page) */ void unpin_user_page(struct page *page) { + int refs = 1; + page = compound_head(page); /* @@ -168,7 +221,12 @@ void unpin_user_page(struct page *page) if (__unpin_devmap_managed_user_page(page)) return; - if (page_ref_sub_and_test(page, GUP_PIN_COUNTING_BIAS)) + if (hpage_pincount_available(page)) + hpage_pincount_sub(page, 1); + else + refs = GUP_PIN_COUNTING_BIAS; + + if (page_ref_sub_and_test(page, refs)) __put_page(page); } EXPORT_SYMBOL(unpin_user_page); @@ -1955,8 +2013,12 @@ EXPORT_SYMBOL(get_user_pages_unlocked); static void put_compound_head(struct page *page, int refs, unsigned int flags) { - if (flags & FOLL_PIN) - refs *= GUP_PIN_COUNTING_BIAS; + if (flags & FOLL_PIN) { + if (hpage_pincount_available(page)) + hpage_pincount_sub(page, refs); + else + refs *= GUP_PIN_COUNTING_BIAS; + } VM_BUG_ON_PAGE(page_ref_count(page) < refs, page); /* diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ba1de6bc1402..3d31a235b53d 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1009,6 +1009,9 @@ static void destroy_compound_gigantic_page(struct page *page, struct page *p = page + 1; atomic_set(compound_mapcount_ptr(page), 0); + if (hpage_pincount_available(page)) + atomic_set(compound_pincount_ptr(page), 0); + for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { clear_compound_head(p); set_page_refcounted(p); @@ -1287,6 +1290,9 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order) set_compound_head(p, page); } atomic_set(compound_mapcount_ptr(page), -1); + + if (hpage_pincount_available(page)) + atomic_set(compound_pincount_ptr(page), 0); } /* diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6e7e9c1d6caa..8f3a3bf2c347 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -688,6 +688,8 @@ void prep_compound_page(struct page *page, unsigned int order) set_compound_head(p, page); } atomic_set(compound_mapcount_ptr(page), -1); + if (hpage_pincount_available(page)) + atomic_set(compound_pincount_ptr(page), 0); } #ifdef CONFIG_DEBUG_PAGEALLOC diff --git a/mm/rmap.c b/mm/rmap.c index b3e381919835..e45b9b991e2f 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1178,6 +1178,9 @@ void page_add_new_anon_rmap(struct page *page, VM_BUG_ON_PAGE(!PageTransHuge(page), page); /* increment count (starts at -1) */ atomic_set(compound_mapcount_ptr(page), 0); + if (hpage_pincount_available(page)) + atomic_set(compound_pincount_ptr(page), 0); + __inc_node_page_state(page, NR_ANON_THPS); } else { /* Anon THP always mapped first with PMD */ @@ -1974,6 +1977,9 @@ void hugepage_add_new_anon_rmap(struct page *page, { BUG_ON(address < vma->vm_start || address >= vma->vm_end); atomic_set(compound_mapcount_ptr(page), 0); + if (hpage_pincount_available(page)) + atomic_set(compound_pincount_ptr(page), 0); + __page_set_anon_rmap(page, vma, address, 1); } #endif /* CONFIG_HUGETLB_PAGE */ |