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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>,
	linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org
Subject: [PATCH 5/9] iomap: Support arbitrarily many blocks per page
Date: Mon, 24 Aug 2020 15:55:06 +0100	[thread overview]
Message-ID: <20200824145511.10500-6-willy@infradead.org> (raw)
In-Reply-To: <20200824145511.10500-1-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>
---
 fs/iomap/buffered-io.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index dbf9572dabe9..844e95cacea8 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -22,18 +22,19 @@
 #include "../internal.h"
 
 /*
- * Structure allocated for each page when block size < PAGE_SIZE to track
+ * Structure allocated for each page 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)
 {
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
 	if (page_has_private(page))
 		return (struct iomap_page *)page_private(page);
 	return NULL;
@@ -45,11 +46,13 @@ 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 +62,14 @@ 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:[~2020-08-24 15:11 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-24 14:55 [PATCH 0/9] THP iomap patches for 5.10 Matthew Wilcox (Oracle)
2020-08-24 14:55 ` [PATCH 1/9] iomap: Fix misplaced page flushing Matthew Wilcox (Oracle)
2020-08-24 23:51   ` Dave Chinner
2020-08-25 20:47   ` Darrick J. Wong
2020-08-27  8:24   ` Christoph Hellwig
2020-08-24 14:55 ` [PATCH 2/9] fs: Introduce i_blocks_per_page Matthew Wilcox (Oracle)
2020-08-24 23:55   ` Dave Chinner
2020-08-25 20:49   ` Darrick J. Wong
2020-08-25 22:21     ` Dave Chinner
2020-08-24 14:55 ` [PATCH 3/9] iomap: Use kzalloc to allocate iomap_page Matthew Wilcox (Oracle)
2020-08-24 23:56   ` Dave Chinner
2020-08-25 20:49   ` Darrick J. Wong
2020-08-24 14:55 ` [PATCH 4/9] iomap: Use bitmap ops to set uptodate bits Matthew Wilcox (Oracle)
2020-08-24 23:56   ` Dave Chinner
2020-08-25 20:50   ` Darrick J. Wong
2020-08-24 14:55 ` Matthew Wilcox (Oracle) [this message]
2020-08-24 23:59   ` [PATCH 5/9] iomap: Support arbitrarily many blocks per page Dave Chinner
2020-08-25  0:22     ` Matthew Wilcox
2020-08-25 21:02   ` Darrick J. Wong
2020-08-26  2:26     ` Matthew Wilcox
2020-08-26  3:32       ` Darrick J. Wong
2020-08-27  8:26   ` Christoph Hellwig
2020-08-24 14:55 ` [PATCH 6/9] iomap: Convert read_count to byte count Matthew Wilcox (Oracle)
2020-08-25  0:09   ` Dave Chinner
2020-08-25 22:14     ` Darrick J. Wong
2020-08-27  8:35   ` Christoph Hellwig
2020-08-24 14:55 ` [PATCH 7/9] iomap: Convert write_count " Matthew Wilcox (Oracle)
2020-08-27  8:36   ` Christoph Hellwig
2020-08-24 14:55 ` [PATCH 8/9] iomap: Convert iomap_write_end types Matthew Wilcox (Oracle)
2020-08-25  0:12   ` Dave Chinner
2020-08-25  1:06     ` Matthew Wilcox
2020-08-25  1:33       ` Dave Chinner
2020-08-27  8:41   ` Christoph Hellwig
2020-08-24 14:55 ` [PATCH 9/9] iomap: Change calling convention for zeroing Matthew Wilcox (Oracle)
2020-08-25  0:27   ` Dave Chinner
2020-08-25  3:26     ` Matthew Wilcox
2020-08-25  3:35       ` Andreas Dilger
2020-08-25  4:27         ` Dave Chinner
2020-08-25 12:40           ` Matthew Wilcox
2020-08-25 22:05             ` Dave Chinner
2020-08-25 22:23   ` Darrick J. Wong
2020-08-27  8:39     ` Christoph Hellwig

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