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From: Joao Martins <joao.m.martins@oracle.com>
To: linux-mm@kvack.org
Cc: linux-nvdimm@lists.01.org, Matthew Wilcox <willy@infradead.org>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Muchun Song <songmuchun@bytedance.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Joao Martins <joao.m.martins@oracle.com>
Subject: [PATCH RFC 7/9] mm/gup: Decrement head page once for group of subpages
Date: Tue,  8 Dec 2020 17:28:59 +0000	[thread overview]
Message-ID: <20201208172901.17384-9-joao.m.martins@oracle.com> (raw)
In-Reply-To: <20201208172901.17384-1-joao.m.martins@oracle.com>

Rather than decrementing the ref count one by one, we
walk the page array and checking which belong to the same
compound_head. Later on we decrement the calculated amount
of references in a single write to the head page.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 mm/gup.c | 41 ++++++++++++++++++++++++++++++++---------
 1 file changed, 32 insertions(+), 9 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 194e6981eb03..3a9a7229f418 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -212,6 +212,18 @@ static bool __unpin_devmap_managed_user_page(struct page *page)
 }
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
 
+static int record_refs(struct page **pages, int npages)
+{
+	struct page *head = compound_head(pages[0]);
+	int refs = 1, index;
+
+	for (index = 1; index < npages; index++, refs++)
+		if (compound_head(pages[index]) != head)
+			break;
+
+	return refs;
+}
+
 /**
  * unpin_user_page() - release a dma-pinned page
  * @page:            pointer to page to be released
@@ -221,9 +233,9 @@ static bool __unpin_devmap_managed_user_page(struct page *page)
  * that such pages can be separately tracked and uniquely handled. In
  * particular, interactions with RDMA and filesystems need special handling.
  */
-void unpin_user_page(struct page *page)
+static void __unpin_user_page(struct page *page, int refs)
 {
-	int refs = 1;
+	int orig_refs = refs;
 
 	page = compound_head(page);
 
@@ -237,14 +249,19 @@ void unpin_user_page(struct page *page)
 		return;
 
 	if (hpage_pincount_available(page))
-		hpage_pincount_sub(page, 1);
+		hpage_pincount_sub(page, refs);
 	else
-		refs = GUP_PIN_COUNTING_BIAS;
+		refs *= GUP_PIN_COUNTING_BIAS;
 
 	if (page_ref_sub_and_test(page, refs))
 		__put_page(page);
 
-	mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED, 1);
+	mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED, orig_refs);
+}
+
+void unpin_user_page(struct page *page)
+{
+	__unpin_user_page(page, 1);
 }
 EXPORT_SYMBOL(unpin_user_page);
 
@@ -274,6 +291,7 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
 				 bool make_dirty)
 {
 	unsigned long index;
+	int refs = 1;
 
 	/*
 	 * TODO: this can be optimized for huge pages: if a series of pages is
@@ -286,8 +304,9 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
 		return;
 	}
 
-	for (index = 0; index < npages; index++) {
+	for (index = 0; index < npages; index += refs) {
 		struct page *page = compound_head(pages[index]);
+
 		/*
 		 * Checking PageDirty at this point may race with
 		 * clear_page_dirty_for_io(), but that's OK. Two key
@@ -310,7 +329,8 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
 		 */
 		if (!PageDirty(page))
 			set_page_dirty_lock(page);
-		unpin_user_page(page);
+		refs = record_refs(pages + index, npages - index);
+		__unpin_user_page(page, refs);
 	}
 }
 EXPORT_SYMBOL(unpin_user_pages_dirty_lock);
@@ -327,6 +347,7 @@ EXPORT_SYMBOL(unpin_user_pages_dirty_lock);
 void unpin_user_pages(struct page **pages, unsigned long npages)
 {
 	unsigned long index;
+	int refs = 1;
 
 	/*
 	 * If this WARN_ON() fires, then the system *might* be leaking pages (by
@@ -340,8 +361,10 @@ void unpin_user_pages(struct page **pages, unsigned long npages)
 	 * physically contiguous and part of the same compound page, then a
 	 * single operation to the head page should suffice.
 	 */
-	for (index = 0; index < npages; index++)
-		unpin_user_page(pages[index]);
+	for (index = 0; index < npages; index += refs) {
+		refs = record_refs(pages + index, npages - index);
+		__unpin_user_page(pages[index], refs);
+	}
 }
 EXPORT_SYMBOL(unpin_user_pages);
 
-- 
2.17.1
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WARNING: multiple messages have this Message-ID
From: Joao Martins <joao.m.martins@oracle.com>
To: linux-mm@kvack.org
Cc: Dan Williams <dan.j.williams@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	linux-nvdimm@lists.01.org, Matthew Wilcox <willy@infradead.org>,
	Jason Gunthorpe <jgg@ziepe.ca>, Jane Chu <jane.chu@oracle.com>,
	Muchun Song <songmuchun@bytedance.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Joao Martins <joao.m.martins@oracle.com>
Subject: [PATCH RFC 7/9] mm/gup: Decrement head page once for group of subpages
Date: Tue,  8 Dec 2020 17:28:59 +0000	[thread overview]
Message-ID: <20201208172901.17384-9-joao.m.martins@oracle.com> (raw)
In-Reply-To: <20201208172901.17384-1-joao.m.martins@oracle.com>

Rather than decrementing the ref count one by one, we
walk the page array and checking which belong to the same
compound_head. Later on we decrement the calculated amount
of references in a single write to the head page.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 mm/gup.c | 41 ++++++++++++++++++++++++++++++++---------
 1 file changed, 32 insertions(+), 9 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 194e6981eb03..3a9a7229f418 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -212,6 +212,18 @@ static bool __unpin_devmap_managed_user_page(struct page *page)
 }
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
 
+static int record_refs(struct page **pages, int npages)
+{
+	struct page *head = compound_head(pages[0]);
+	int refs = 1, index;
+
+	for (index = 1; index < npages; index++, refs++)
+		if (compound_head(pages[index]) != head)
+			break;
+
+	return refs;
+}
+
 /**
  * unpin_user_page() - release a dma-pinned page
  * @page:            pointer to page to be released
@@ -221,9 +233,9 @@ static bool __unpin_devmap_managed_user_page(struct page *page)
  * that such pages can be separately tracked and uniquely handled. In
  * particular, interactions with RDMA and filesystems need special handling.
  */
-void unpin_user_page(struct page *page)
+static void __unpin_user_page(struct page *page, int refs)
 {
-	int refs = 1;
+	int orig_refs = refs;
 
 	page = compound_head(page);
 
@@ -237,14 +249,19 @@ void unpin_user_page(struct page *page)
 		return;
 
 	if (hpage_pincount_available(page))
-		hpage_pincount_sub(page, 1);
+		hpage_pincount_sub(page, refs);
 	else
-		refs = GUP_PIN_COUNTING_BIAS;
+		refs *= GUP_PIN_COUNTING_BIAS;
 
 	if (page_ref_sub_and_test(page, refs))
 		__put_page(page);
 
-	mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED, 1);
+	mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED, orig_refs);
+}
+
+void unpin_user_page(struct page *page)
+{
+	__unpin_user_page(page, 1);
 }
 EXPORT_SYMBOL(unpin_user_page);
 
@@ -274,6 +291,7 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
 				 bool make_dirty)
 {
 	unsigned long index;
+	int refs = 1;
 
 	/*
 	 * TODO: this can be optimized for huge pages: if a series of pages is
@@ -286,8 +304,9 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
 		return;
 	}
 
-	for (index = 0; index < npages; index++) {
+	for (index = 0; index < npages; index += refs) {
 		struct page *page = compound_head(pages[index]);
+
 		/*
 		 * Checking PageDirty at this point may race with
 		 * clear_page_dirty_for_io(), but that's OK. Two key
@@ -310,7 +329,8 @@ void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
 		 */
 		if (!PageDirty(page))
 			set_page_dirty_lock(page);
-		unpin_user_page(page);
+		refs = record_refs(pages + index, npages - index);
+		__unpin_user_page(page, refs);
 	}
 }
 EXPORT_SYMBOL(unpin_user_pages_dirty_lock);
@@ -327,6 +347,7 @@ EXPORT_SYMBOL(unpin_user_pages_dirty_lock);
 void unpin_user_pages(struct page **pages, unsigned long npages)
 {
 	unsigned long index;
+	int refs = 1;
 
 	/*
 	 * If this WARN_ON() fires, then the system *might* be leaking pages (by
@@ -340,8 +361,10 @@ void unpin_user_pages(struct page **pages, unsigned long npages)
 	 * physically contiguous and part of the same compound page, then a
 	 * single operation to the head page should suffice.
 	 */
-	for (index = 0; index < npages; index++)
-		unpin_user_page(pages[index]);
+	for (index = 0; index < npages; index += refs) {
+		refs = record_refs(pages + index, npages - index);
+		__unpin_user_page(pages[index], refs);
+	}
 }
 EXPORT_SYMBOL(unpin_user_pages);
 
-- 
2.17.1



  parent reply	other threads:[~2020-12-08 17:30 UTC|newest]

Thread overview: 147+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-08 17:28 [PATCH RFC 0/9] mm, sparse-vmemmap: Introduce compound pagemaps Joao Martins
2020-12-08 17:28 ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 1/9] memremap: add ZONE_DEVICE support for compound pages Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-09  5:59   ` John Hubbard
2020-12-09  5:59     ` John Hubbard
2020-12-09  6:33     ` Matthew Wilcox
2020-12-09  6:33       ` Matthew Wilcox
2020-12-09 13:12       ` Joao Martins
2020-12-09 13:12         ` Joao Martins
2021-02-20  1:43     ` Dan Williams
2021-02-20  1:43       ` Dan Williams
2021-02-22 11:24       ` Joao Martins
2021-02-22 11:24         ` Joao Martins
2021-02-22 20:37         ` Dan Williams
2021-02-22 20:37           ` Dan Williams
2021-02-23 15:46           ` Joao Martins
2021-02-23 15:46             ` Joao Martins
2021-02-23 16:50             ` Dan Williams
2021-02-23 16:50               ` Dan Williams
2021-02-23 17:18               ` Joao Martins
2021-02-23 17:18                 ` Joao Martins
2021-02-23 18:18                 ` Dan Williams
2021-02-23 18:18                   ` Dan Williams
2021-03-10 18:12           ` Joao Martins
2021-03-10 18:12             ` Joao Martins
2021-03-12  5:54             ` Dan Williams
2021-03-12  5:54               ` Dan Williams
2021-02-20  1:24   ` Dan Williams
2021-02-20  1:24     ` Dan Williams
2021-02-22 11:09     ` Joao Martins
2021-02-22 11:09       ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 2/9] sparse-vmemmap: Consolidate arguments in vmemmap section populate Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-09  6:16   ` John Hubbard
2020-12-09  6:16     ` John Hubbard
2020-12-09 13:51     ` Joao Martins
2020-12-09 13:51       ` Joao Martins
2021-02-20  1:49   ` Dan Williams
2021-02-20  1:49     ` Dan Williams
2021-02-22 11:26     ` Joao Martins
2021-02-22 11:26       ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 3/9] sparse-vmemmap: Reuse vmemmap areas for a given mhp_params::align Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-08 17:38   ` Joao Martins
2020-12-08 17:38     ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 3/9] sparse-vmemmap: Reuse vmemmap areas for a given page size Joao Martins
2020-12-08 17:28   ` Joao Martins
2021-02-20  3:34   ` Dan Williams
2021-02-20  3:34     ` Dan Williams
2021-02-22 11:42     ` Joao Martins
2021-02-22 11:42       ` Joao Martins
2021-02-22 22:40       ` Dan Williams
2021-02-22 22:40         ` Dan Williams
2021-02-23 15:46         ` Joao Martins
2021-02-23 15:46           ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 4/9] mm/page_alloc: Reuse tail struct pages for compound pagemaps Joao Martins
2020-12-08 17:28   ` Joao Martins
2021-02-20  6:17   ` Dan Williams
2021-02-20  6:17     ` Dan Williams
2021-02-22 12:01     ` Joao Martins
2021-02-22 12:01       ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 5/9] device-dax: Compound pagemap support Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-08 17:28 ` [PATCH RFC 6/9] mm/gup: Grab head page refcount once for group of subpages Joao Martins
2020-12-08 17:28   ` Joao Martins
2020-12-08 19:49   ` Jason Gunthorpe
2020-12-09 11:05     ` Joao Martins
2020-12-09 11:05       ` Joao Martins
2020-12-09 15:15       ` Jason Gunthorpe
2020-12-09 16:02         ` Joao Martins
2020-12-09 16:02           ` Joao Martins
2020-12-09 16:24           ` Jason Gunthorpe
2020-12-09 17:27             ` Joao Martins
2020-12-09 17:27               ` Joao Martins
2020-12-09 18:14             ` Matthew Wilcox
2020-12-09 18:14               ` Matthew Wilcox
2020-12-09 19:08               ` Jason Gunthorpe
2020-12-10 15:43               ` Joao Martins
2020-12-10 15:43                 ` Joao Martins
2020-12-09  4:40   ` John Hubbard
2020-12-09  4:40     ` John Hubbard
2020-12-09 13:44     ` Joao Martins
2020-12-09 13:44       ` Joao Martins
2020-12-08 17:28 ` Joao Martins [this message]
2020-12-08 17:28   ` [PATCH RFC 7/9] mm/gup: Decrement head page " Joao Martins
2020-12-08 19:34   ` Jason Gunthorpe
2020-12-09  5:06     ` John Hubbard
2020-12-09  5:06       ` John Hubbard
2020-12-09 13:43       ` Jason Gunthorpe
2020-12-09 12:17     ` Joao Martins
2020-12-09 12:17       ` Joao Martins
2020-12-17 19:05     ` Joao Martins
2020-12-17 19:05       ` Joao Martins
2020-12-17 20:05       ` Jason Gunthorpe
2020-12-17 22:34         ` Joao Martins
2020-12-17 22:34           ` Joao Martins
2020-12-18 14:25           ` Jason Gunthorpe
2020-12-19  2:06         ` John Hubbard
2020-12-19  2:06           ` John Hubbard
2020-12-19 13:10           ` Joao Martins
2020-12-19 13:10             ` Joao Martins
2020-12-08 17:29 ` [PATCH RFC 8/9] RDMA/umem: batch page unpin in __ib_mem_release() Joao Martins
2020-12-08 17:29   ` Joao Martins
2020-12-08 19:29   ` Jason Gunthorpe
2020-12-09 10:59     ` Joao Martins
2020-12-09 10:59       ` Joao Martins
2020-12-19 13:15       ` Joao Martins
2020-12-19 13:15         ` Joao Martins
2020-12-09  5:18   ` John Hubbard
2020-12-09  5:18     ` John Hubbard
2020-12-08 17:29 ` [PATCH RFC 9/9] mm: Add follow_devmap_page() for devdax vmas Joao Martins
2020-12-08 17:29   ` Joao Martins
2020-12-08 19:57   ` Jason Gunthorpe
2020-12-09  8:05     ` Christoph Hellwig
2020-12-09  8:05       ` Christoph Hellwig
2020-12-09 11:19     ` Joao Martins
2020-12-09 11:19       ` Joao Martins
2020-12-09  5:23   ` John Hubbard
2020-12-09  5:23     ` John Hubbard
2020-12-09  9:38 ` [PATCH RFC 0/9] mm, sparse-vmemmap: Introduce compound pagemaps David Hildenbrand
2020-12-09  9:38   ` David Hildenbrand
2020-12-09  9:52 ` [External] " Muchun Song
2020-12-09  9:52   ` Muchun Song
2021-02-20  1:18 ` Dan Williams
2021-02-20  1:18   ` Dan Williams
2021-02-22 11:06   ` Joao Martins
2021-02-22 11:06     ` Joao Martins
2021-02-22 14:32     ` Joao Martins
2021-02-22 14:32       ` Joao Martins
2021-02-23 16:28   ` Joao Martins
2021-02-23 16:28     ` Joao Martins
2021-02-23 16:44     ` Dan Williams
2021-02-23 16:44       ` Dan Williams
2021-02-23 17:15       ` Joao Martins
2021-02-23 17:15         ` Joao Martins
2021-02-23 18:15         ` Dan Williams
2021-02-23 18:15           ` Dan Williams
2021-02-23 18:54       ` Jason Gunthorpe
2021-02-23 22:48         ` Dan Williams
2021-02-23 22:48           ` Dan Williams
2021-02-23 23:07           ` Jason Gunthorpe
2021-02-24  0:14             ` Dan Williams
2021-02-24  0:14               ` Dan Williams
2021-02-24  1:00               ` Jason Gunthorpe
2021-02-24  1:32                 ` Dan Williams
2021-02-24  1:32                   ` Dan Williams

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