On 1/9/22 20:23, Matthew Wilcox (Oracle) wrote:
Convert put_compound_head() to gup_put_folio() and hpage_pincount_sub()
to folio_pincount_sub(). This removes the last call to put_page_refs(),
so delete it. Add a temporary put_compound_head() wrapper which will
be deleted by the end of this series.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
mm/gup.c | 42 ++++++++++++++----------------------------
1 file changed, 14 insertions(+), 28 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 9e581201d679..719252fa0402 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -45,34 +45,15 @@ static void folio_pincount_add(struct folio *folio, int refs)
folio_ref_add(folio, refs * (GUP_PIN_COUNTING_BIAS - 1));
}
-static int page_pincount_sub(struct page *page, int refs)
+static int folio_pincount_sub(struct folio *folio, int refs)
I just noticed that this return value was a little hard to reason about, which
prompted me to notice that I'd skipped reviewing patch 10. So I went back
and added a note there. :)
Anyway, this one looks good,
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
thanks,
--
John Hubbard
NVIDIA
{
- VM_BUG_ON_PAGE(page != compound_head(page), page);
-
- if (PageHead(page))
- atomic_sub(refs, compound_pincount_ptr(page));
+ if (folio_test_large(folio))
+ atomic_sub(refs, folio_pincount_ptr(folio));
else
refs *= GUP_PIN_COUNTING_BIAS;
return refs;
}
-/* Equivalent to calling put_page() @refs times. */
-static void put_page_refs(struct page *page, int refs)
-{
-#ifdef CONFIG_DEBUG_VM
- if (VM_WARN_ON_ONCE_PAGE(page_ref_count(page) < refs, page))
- return;
-#endif
-
- /*
- * Calling put_page() for each ref is unnecessarily slow. Only the last
- * ref needs a put_page().
- */
- if (refs > 1)
- page_ref_sub(page, refs - 1);
- put_page(page);
-}
-
/*
* Return the folio with ref appropriately incremented,
* or NULL if that failed.
@@ -171,15 +152,20 @@ struct page *try_grab_compound_head(struct page *page,
return &try_grab_folio(page, refs, flags)->page;
}
-static void put_compound_head(struct page *page, int refs, unsigned int flags)
+static void gup_put_folio(struct folio *folio, int refs, unsigned int flags)
{
if (flags & FOLL_PIN) {
- mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED,
- refs);
- refs = page_pincount_sub(page, refs);
+ node_stat_mod_folio(folio, NR_FOLL_PIN_RELEASED, refs);
+ refs = folio_pincount_sub(folio, refs);
}
- put_page_refs(page, refs);
+ folio_put_refs(folio, refs);
+}
+
+static void put_compound_head(struct page *page, int refs, unsigned int flags)
+{
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ gup_put_folio((struct folio *)page, refs, flags);
}
/**
@@ -220,7 +206,7 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags)
*/
void unpin_user_page(struct page *page)
{
- put_compound_head(compound_head(page), 1, FOLL_PIN);
+ gup_put_folio(page_folio(page), 1, FOLL_PIN);
}
EXPORT_SYMBOL(unpin_user_page);
