| Message ID | 20210511214735.1836149-34-willy@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Memory folios | expand |
On 5/11/21 11:47 PM, Matthew Wilcox (Oracle) wrote: > This function is the equivalent of page_mapped(). It is slightly > shorter as we do not need to handle the PageTail() case. Reimplement > page_mapped() as a wrapper around folio_mapped(). > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz>
On Tue, May 11, 2021 at 10:47:35PM +0100, Matthew Wilcox (Oracle) wrote: > This function is the equivalent of page_mapped(). It is slightly > shorter as we do not need to handle the PageTail() case. Reimplement > page_mapped() as a wrapper around folio_mapped(). No byte savings numbers as for the other patches? The patch itself looks good, although I'd go for a slightly easier readable structure: bool folio_mapped(struct folio *folio) { if (folio_single(folio)) return atomic_read(&folio->_mapcount) >= 0; if (atomic_read(compound_mapcount_ptr(&folio->page)) >= 0) return true; if (!folio_hugetlb(folio)) { unsigned long i; for (i = 0; i < folio_nr_pages(folio); i++) if (atomic_read(&folio_page(folio, i)->_mapcount) >= 0) return true; } return false; } Shouldn't we also have a folio version of compound_mapcount_ptr?
diff --git a/include/linux/mm.h b/include/linux/mm.h index 6e3dde81ecc9..4686107a4f96 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1779,6 +1779,7 @@ static inline pgoff_t page_index(struct page *page) } bool page_mapped(struct page *page); +bool folio_mapped(struct folio *folio); /* * Return true only if the page has been allocated with diff --git a/mm/folio-compat.c b/mm/folio-compat.c index 3c83f03b80d7..7044fcc8a8aa 100644 --- a/mm/folio-compat.c +++ b/mm/folio-compat.c @@ -35,3 +35,9 @@ void wait_for_stable_page(struct page *page) return folio_wait_stable(page_folio(page)); } EXPORT_SYMBOL_GPL(wait_for_stable_page); + +bool page_mapped(struct page *page) +{ + return folio_mapped(page_folio(page)); +} +EXPORT_SYMBOL(page_mapped); diff --git a/mm/util.c b/mm/util.c index 245f5c7bedae..c2d22145ebae 100644 --- a/mm/util.c +++ b/mm/util.c @@ -652,28 +652,31 @@ void *page_rmapping(struct page *page) return __page_rmapping(page); } -/* - * Return true if this page is mapped into pagetables. - * For compound page it returns true if any subpage of compound page is mapped. +/** + * folio_mapped - Is this folio mapped into userspace? + * @folio: The folio. + * + * Return: true if any page in this folio is mapped into pagetables. */ -bool page_mapped(struct page *page) +bool folio_mapped(struct folio *folio) { - int i; + int i, nr; - if (likely(!PageCompound(page))) - return atomic_read(&page->_mapcount) >= 0; - page = compound_head(page); - if (atomic_read(compound_mapcount_ptr(page)) >= 0) + if (folio_single(folio)) + return atomic_read(&folio->_mapcount) >= 0; + if (atomic_read(compound_mapcount_ptr(&folio->page)) >= 0) return true; - if (PageHuge(page)) + if (folio_hugetlb(folio)) return false; - for (i = 0; i < compound_nr(page); i++) { - if (atomic_read(&page[i]._mapcount) >= 0) + + nr = folio_nr_pages(folio); + for (i = 0; i < nr; i++) { + if (atomic_read(&folio_page(folio, i)->_mapcount) >= 0) return true; } return false; } -EXPORT_SYMBOL(page_mapped); +EXPORT_SYMBOL(folio_mapped); struct anon_vma *page_anon_vma(struct page *page) {
This function is the equivalent of page_mapped(). It is slightly shorter as we do not need to handle the PageTail() case. Reimplement page_mapped() as a wrapper around folio_mapped(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- include/linux/mm.h | 1 + mm/folio-compat.c | 6 ++++++ mm/util.c | 29 ++++++++++++++++------------- 3 files changed, 23 insertions(+), 13 deletions(-)