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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Darrick J . Wong" <darrick.wong@oracle.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org,
	Dave Kleikamp <shaggy@kernel.org>,
	jfs-discussion@lists.sourceforge.net,
	Dave Chinner <dchinner@redhat.com>
Subject: [PATCH v2 5/9] iomap: Support arbitrarily many blocks per page
Date: Fri, 11 Sep 2020 00:47:03 +0100	[thread overview]
Message-ID: <20200910234707.5504-6-willy@infradead.org> (raw)
In-Reply-To: <20200910234707.5504-1-willy@infradead.org>

Size the uptodate array dynamically to support larger pages in the
page cache.  With a 64kB page, we're only saving 8 bytes per page today,
but with a 2MB maximum page size, we'd have to allocate more than 4kB
per page.  Add a few debugging assertions.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/iomap/buffered-io.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 7fc0e02d27b0..9670c096b83e 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -22,18 +22,25 @@
 #include "../internal.h"
 
 /*
- * Structure allocated for each page when block size < PAGE_SIZE to track
- * sub-page uptodate status and I/O completions.
+ * Structure allocated for each page or THP when block size < page size
+ * to track sub-page uptodate status and I/O completions.
  */
 struct iomap_page {
 	atomic_t		read_count;
 	atomic_t		write_count;
 	spinlock_t		uptodate_lock;
-	DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
+	unsigned long		uptodate[];
 };
 
 static inline struct iomap_page *to_iomap_page(struct page *page)
 {
+	/*
+	 * per-block data is stored in the head page.  Callers should
+	 * not be dealing with tail pages (and if they are, they can
+	 * call thp_head() first.
+	 */
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
+
 	if (page_has_private(page))
 		return (struct iomap_page *)page_private(page);
 	return NULL;
@@ -45,11 +52,13 @@ static struct iomap_page *
 iomap_page_create(struct inode *inode, struct page *page)
 {
 	struct iomap_page *iop = to_iomap_page(page);
+	unsigned int nr_blocks = i_blocks_per_page(inode, page);
 
-	if (iop || i_blocks_per_page(inode, page) <= 1)
+	if (iop || nr_blocks <= 1)
 		return iop;
 
-	iop = kzalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
+	iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)),
+			GFP_NOFS | __GFP_NOFAIL);
 	spin_lock_init(&iop->uptodate_lock);
 	attach_page_private(page, iop);
 	return iop;
@@ -59,11 +68,14 @@ static void
 iomap_page_release(struct page *page)
 {
 	struct iomap_page *iop = detach_page_private(page);
+	unsigned int nr_blocks = i_blocks_per_page(page->mapping->host, page);
 
 	if (!iop)
 		return;
 	WARN_ON_ONCE(atomic_read(&iop->read_count));
 	WARN_ON_ONCE(atomic_read(&iop->write_count));
+	WARN_ON_ONCE(bitmap_full(iop->uptodate, nr_blocks) !=
+			PageUptodate(page));
 	kfree(iop);
 }
 
-- 
2.28.0
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WARNING: multiple messages have this Message-ID (diff)
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Darrick J . Wong" <darrick.wong@oracle.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org,
	Dave Kleikamp <shaggy@kernel.org>,
	jfs-discussion@lists.sourceforge.net,
	Dave Chinner <dchinner@redhat.com>
Subject: [PATCH v2 5/9] iomap: Support arbitrarily many blocks per page
Date: Fri, 11 Sep 2020 00:47:03 +0100	[thread overview]
Message-ID: <20200910234707.5504-6-willy@infradead.org> (raw)
In-Reply-To: <20200910234707.5504-1-willy@infradead.org>

Size the uptodate array dynamically to support larger pages in the
page cache.  With a 64kB page, we're only saving 8 bytes per page today,
but with a 2MB maximum page size, we'd have to allocate more than 4kB
per page.  Add a few debugging assertions.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/iomap/buffered-io.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 7fc0e02d27b0..9670c096b83e 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -22,18 +22,25 @@
 #include "../internal.h"
 
 /*
- * Structure allocated for each page when block size < PAGE_SIZE to track
- * sub-page uptodate status and I/O completions.
+ * Structure allocated for each page or THP when block size < page size
+ * to track sub-page uptodate status and I/O completions.
  */
 struct iomap_page {
 	atomic_t		read_count;
 	atomic_t		write_count;
 	spinlock_t		uptodate_lock;
-	DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
+	unsigned long		uptodate[];
 };
 
 static inline struct iomap_page *to_iomap_page(struct page *page)
 {
+	/*
+	 * per-block data is stored in the head page.  Callers should
+	 * not be dealing with tail pages (and if they are, they can
+	 * call thp_head() first.
+	 */
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
+
 	if (page_has_private(page))
 		return (struct iomap_page *)page_private(page);
 	return NULL;
@@ -45,11 +52,13 @@ static struct iomap_page *
 iomap_page_create(struct inode *inode, struct page *page)
 {
 	struct iomap_page *iop = to_iomap_page(page);
+	unsigned int nr_blocks = i_blocks_per_page(inode, page);
 
-	if (iop || i_blocks_per_page(inode, page) <= 1)
+	if (iop || nr_blocks <= 1)
 		return iop;
 
-	iop = kzalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
+	iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)),
+			GFP_NOFS | __GFP_NOFAIL);
 	spin_lock_init(&iop->uptodate_lock);
 	attach_page_private(page, iop);
 	return iop;
@@ -59,11 +68,14 @@ static void
 iomap_page_release(struct page *page)
 {
 	struct iomap_page *iop = detach_page_private(page);
+	unsigned int nr_blocks = i_blocks_per_page(page->mapping->host, page);
 
 	if (!iop)
 		return;
 	WARN_ON_ONCE(atomic_read(&iop->read_count));
 	WARN_ON_ONCE(atomic_read(&iop->write_count));
+	WARN_ON_ONCE(bitmap_full(iop->uptodate, nr_blocks) !=
+			PageUptodate(page));
 	kfree(iop);
 }
 
-- 
2.28.0


  parent reply	other threads:[~2020-09-10 23:47 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-10 23:46 [PATCH v2 0/9] THP iomap patches for 5.10 Matthew Wilcox (Oracle)
2020-09-10 23:46 ` Matthew Wilcox (Oracle)
2020-09-10 23:46 ` [PATCH v2 1/9] iomap: Fix misplaced page flushing Matthew Wilcox (Oracle)
2020-09-10 23:46   ` Matthew Wilcox (Oracle)
2020-09-10 23:47 ` [PATCH v2 2/9] fs: Introduce i_blocks_per_page Matthew Wilcox (Oracle)
2020-09-10 23:47   ` Matthew Wilcox (Oracle)
2020-09-15 14:58   ` Dave Kleikamp
2020-09-15 14:58     ` Dave Kleikamp
2020-09-15 15:40   ` David Laight
2020-09-15 15:40     ` David Laight
2020-09-15 15:49     ` Matthew Wilcox
2020-09-15 15:49       ` Matthew Wilcox
2020-09-10 23:47 ` [PATCH v2 3/9] iomap: Use kzalloc to allocate iomap_page Matthew Wilcox (Oracle)
2020-09-10 23:47   ` Matthew Wilcox (Oracle)
2020-09-10 23:47 ` [PATCH v2 4/9] iomap: Use bitmap ops to set uptodate bits Matthew Wilcox (Oracle)
2020-09-10 23:47   ` Matthew Wilcox (Oracle)
2020-09-10 23:47 ` Matthew Wilcox (Oracle) [this message]
2020-09-10 23:47   ` [PATCH v2 5/9] iomap: Support arbitrarily many blocks per page Matthew Wilcox (Oracle)
2020-09-11  5:36   ` Christoph Hellwig
2020-09-11  5:36     ` Christoph Hellwig
2020-09-17 22:00   ` Darrick J. Wong
2020-09-17 22:00     ` Darrick J. Wong
2020-09-22 16:23   ` Qian Cai
2020-09-22 16:23     ` Qian Cai
2020-09-22 17:05     ` Matthew Wilcox
2020-09-22 17:05       ` Matthew Wilcox
2020-09-22 17:25       ` Qian Cai
2020-09-22 17:25         ` Qian Cai
2020-09-23  1:06       ` Qian Cai
2020-09-23  1:06         ` Qian Cai
2020-09-23  2:48         ` Matthew Wilcox
2020-09-23  2:48           ` Matthew Wilcox
2020-09-23  5:00           ` Darrick J. Wong
2020-09-23  5:00             ` Darrick J. Wong
2020-09-23 18:59             ` Matthew Wilcox
2020-09-23 18:59               ` Matthew Wilcox
2020-09-23 16:55           ` Qian Cai
2020-09-23 16:55             ` Qian Cai
2020-09-24  1:07       ` Matthew Wilcox
2020-09-24  1:07         ` Matthew Wilcox
2020-09-10 23:47 ` [PATCH v2 6/9] iomap: Convert read_count to read_bytes_pending Matthew Wilcox (Oracle)
2020-09-10 23:47   ` Matthew Wilcox (Oracle)
2020-09-11  5:36   ` Christoph Hellwig
2020-09-11  5:36     ` Christoph Hellwig
2020-09-17 22:02   ` Darrick J. Wong
2020-09-17 22:02     ` Darrick J. Wong
2020-09-10 23:47 ` [PATCH v2 7/9] iomap: Convert write_count to write_bytes_pending Matthew Wilcox (Oracle)
2020-09-10 23:47   ` Matthew Wilcox (Oracle)
2020-09-17 22:02   ` Darrick J. Wong
2020-09-17 22:02     ` Darrick J. Wong
2020-09-10 23:47 ` [PATCH v2 8/9] iomap: Convert iomap_write_end types Matthew Wilcox (Oracle)
2020-09-10 23:47   ` Matthew Wilcox (Oracle)
2020-09-17 22:03   ` Darrick J. Wong
2020-09-17 22:03     ` Darrick J. Wong
2020-09-10 23:47 ` [PATCH v2 9/9] iomap: Change calling convention for zeroing Matthew Wilcox (Oracle)
2020-09-10 23:47   ` Matthew Wilcox (Oracle)
2020-09-11  6:42   ` Christoph Hellwig
2020-09-11  6:42     ` Christoph Hellwig
2020-09-17 22:05   ` Darrick J. Wong
2020-09-17 22:05     ` Darrick J. Wong
2020-09-17 22:11     ` Matthew Wilcox
2020-09-17 22:11       ` Matthew Wilcox
2020-09-17 22:18       ` Darrick J. Wong
2020-09-17 22:18         ` Darrick J. Wong

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