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From: Matthew Wilcox <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH v6 28/51] iomap: Change iomap_write_begin calling convention
Date: Wed, 10 Jun 2020 13:13:22 -0700	[thread overview]
Message-ID: <20200610201345.13273-29-willy@infradead.org> (raw)
In-Reply-To: <20200610201345.13273-1-willy@infradead.org>

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Pass (up to) the remaining length of the extent to iomap_write_begin()
and have it return the number of bytes that will fit in the page.
That lets us copy more bytes per call to iomap_write_begin() if the page
cache has already allocated a THP (and will in future allow us to pass
a hint to the page cache that it should try to allocate a larger page
if there are none in the cache).

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/iomap/buffered-io.c | 63 +++++++++++++++++++++++-------------------
 1 file changed, 34 insertions(+), 29 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 8d690ad68657..e445ee5f0521 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -571,14 +571,14 @@ iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff,
 	return submit_bio_wait(&bio);
 }
 
-static int
-__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
-		struct page *page, struct iomap *srcmap)
+static ssize_t __iomap_write_begin(struct inode *inode, loff_t pos,
+		size_t len, int flags, struct page *page, struct iomap *srcmap)
 {
 	loff_t block_size = i_blocksize(inode);
 	loff_t block_start = pos & ~(block_size - 1);
 	loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1);
-	unsigned from = offset_in_page(pos), to = from + len;
+	size_t from = offset_in_thp(page, pos);
+	size_t to = from + len;
 	size_t poff, plen;
 	int status;
 
@@ -614,12 +614,13 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
 	return 0;
 }
 
-static int
-iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
-		struct page **pagep, struct iomap *iomap, struct iomap *srcmap)
+static ssize_t iomap_write_begin(struct inode *inode, loff_t pos, loff_t len,
+		unsigned flags, struct page **pagep, struct iomap *iomap,
+		struct iomap *srcmap)
 {
 	const struct iomap_page_ops *page_ops = iomap->page_ops;
 	struct page *page;
+	size_t offset;
 	int status = 0;
 
 	BUG_ON(pos + len > iomap->offset + iomap->length);
@@ -630,6 +631,8 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
 		return -EINTR;
 
 	if (page_ops && page_ops->page_prepare) {
+		if (len > UINT_MAX)
+			len = UINT_MAX;
 		status = page_ops->page_prepare(inode, pos, len, iomap);
 		if (status)
 			return status;
@@ -641,6 +644,10 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
 		status = -ENOMEM;
 		goto out_no_page;
 	}
+	page = thp_head(page);
+	offset = offset_in_thp(page, pos);
+	if (len > thp_size(page) - offset)
+		len = thp_size(page) - offset;
 
 	if (srcmap->type == IOMAP_INLINE)
 		iomap_read_inline_data(inode, page, srcmap);
@@ -650,11 +657,11 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
 		status = __iomap_write_begin(inode, pos, len, flags, page,
 				srcmap);
 
-	if (unlikely(status))
+	if (status < 0)
 		goto out_unlock;
 
 	*pagep = page;
-	return 0;
+	return len;
 
 out_unlock:
 	unlock_page(page);
@@ -809,8 +816,10 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 
 		status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap,
 				srcmap);
-		if (unlikely(status))
+		if (status < 0)
 			break;
+		/* We may be partway through a THP */
+		offset = offset_in_thp(page, pos);
 
 		if (mapping_writably_mapped(inode->i_mapping))
 			flush_dcache_page(page);
@@ -872,8 +881,7 @@ static loff_t
 iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 		struct iomap *iomap, struct iomap *srcmap)
 {
-	long status = 0;
-	ssize_t written = 0;
+	loff_t written = 0;
 
 	/* don't bother with blocks that are not shared to start with */
 	if (!(iomap->flags & IOMAP_F_SHARED))
@@ -883,25 +891,24 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 		return length;
 
 	do {
-		unsigned long offset = offset_in_page(pos);
-		unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length);
 		struct page *page;
+		ssize_t bytes;
 
-		status = iomap_write_begin(inode, pos, bytes,
+		bytes = iomap_write_begin(inode, pos, length,
 				IOMAP_WRITE_F_UNSHARE, &page, iomap, srcmap);
-		if (unlikely(status))
-			return status;
+		if (bytes < 0)
+			return bytes;
 
-		status = iomap_write_end(inode, pos, bytes, bytes, page, iomap,
+		bytes = iomap_write_end(inode, pos, bytes, bytes, page, iomap,
 				srcmap);
-		if (WARN_ON_ONCE(status == 0))
+		if (WARN_ON_ONCE(bytes == 0))
 			return -EIO;
 
 		cond_resched();
 
-		pos += status;
-		written += status;
-		length -= status;
+		pos += bytes;
+		written += bytes;
+		length -= bytes;
 
 		balance_dirty_pages_ratelimited(inode->i_mapping);
 	} while (length);
@@ -932,15 +939,13 @@ static ssize_t iomap_zero(struct inode *inode, loff_t pos, loff_t length,
 		struct iomap *iomap, struct iomap *srcmap)
 {
 	struct page *page;
-	int status;
-	unsigned offset = offset_in_page(pos);
-	unsigned bytes = min_t(loff_t, PAGE_SIZE - offset, length);
+	ssize_t bytes;
 
-	status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, srcmap);
-	if (status)
-		return status;
+	bytes = iomap_write_begin(inode, pos, length, 0, &page, iomap, srcmap);
+	if (bytes < 0)
+		return bytes;
 
-	zero_user(page, offset, bytes);
+	zero_user(page, offset_in_thp(page, pos), bytes);
 	mark_page_accessed(page);
 
 	return iomap_write_end(inode, pos, bytes, bytes, page, iomap, srcmap);
-- 
2.26.2


  parent reply	other threads:[~2020-06-10 20:16 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-10 20:12 [RFC v6 00/51] Large pages in the page cache Matthew Wilcox
2020-06-10 20:12 ` [PATCH v6 01/51] mm: Print head flags in dump_page Matthew Wilcox
2020-06-10 20:12 ` [PATCH v6 02/51] mm: Print the inode number " Matthew Wilcox
2020-06-10 20:12 ` [PATCH v6 03/51] mm: Print hashed address of struct page Matthew Wilcox
2020-06-10 20:12 ` [PATCH v6 04/51] mm: Move PageDoubleMap bit Matthew Wilcox
2020-06-11 15:03   ` Zi Yan
2020-06-10 20:12 ` [PATCH v6 05/51] mm: Simplify PageDoubleMap with PF_SECOND policy Matthew Wilcox
2020-06-11 15:14   ` Zi Yan
2020-06-10 20:13 ` [PATCH v6 06/51] mm: Store compound_nr as well as compound_order Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 07/51] mm: Move page-flags include to top of file Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 08/51] mm: Add thp_order Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 09/51] mm: Add thp_size Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 10/51] mm: Replace hpage_nr_pages with thp_nr_pages Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 11/51] mm: Add thp_head Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 12/51] mm: Introduce offset_in_thp Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 13/51] mm: Support arbitrary THP sizes Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 14/51] fs: Add a filesystem flag for THPs Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 15/51] fs: Do not update nr_thps for mappings which support THPs Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 16/51] fs: Introduce i_blocks_per_page Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 17/51] fs: Make page_mkwrite_check_truncate thp-aware Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 18/51] mm: Support THPs in zero_user_segments Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 19/51] mm: Zero the head page, not the tail page Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 20/51] block: Add bio_for_each_thp_segment_all Matthew Wilcox
2020-06-11 18:20   ` Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 21/51] block: Support THPs in page_is_mergeable Matthew Wilcox
2020-06-12 16:17   ` Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 22/51] iomap: Support arbitrarily many blocks per page Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 23/51] iomap: Support THPs in iomap_adjust_read_range Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 24/51] iomap: Support THPs in invalidatepage Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 25/51] iomap: Support THPs in read paths Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 26/51] iomap: Convert iomap_write_end types Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 27/51] iomap: Change calling convention for zeroing Matthew Wilcox
2020-06-10 20:13 ` Matthew Wilcox [this message]
2020-06-10 20:13 ` [PATCH v6 29/51] iomap: Support THPs in write paths Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 30/51] iomap: Inline data shouldn't see THPs Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 31/51] iomap: Handle tail pages in iomap_page_mkwrite Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 32/51] xfs: Support THPs Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 33/51] mm: Make prep_transhuge_page return its argument Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 34/51] mm: Add __page_cache_alloc_order Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 35/51] mm: Allow THPs to be added to the page cache Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 36/51] mm: Allow THPs to be removed from " Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 37/51] mm: Remove page fault assumption of compound page size Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 38/51] mm: Fix total_mapcount assumption of " Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 39/51] mm: Remove assumptions of THP size Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 40/51] mm: Avoid splitting THPs Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 41/51] mm: Fix truncation for pages of arbitrary size Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 42/51] mm: Handle truncates that split THPs Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 43/51] mm: Support storing shadow entries for THPs Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 44/51] mm: Support retrieving tail pages from the page cache Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 45/51] mm: Support tail pages in wait_for_stable_page Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 46/51] mm: Add DEFINE_READAHEAD Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 47/51] mm: Make page_cache_readahead_unbounded take a readahead_control Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 48/51] mm: Make __do_page_cache_readahead " Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 49/51] mm: Allow PageReadahead to be set on head pages Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 50/51] mm: Add THP readahead Matthew Wilcox
2020-06-10 20:13 ` [PATCH v6 51/51] mm: Align THP mappings for non-DAX Matthew Wilcox
2020-06-11  6:59 ` [RFC v6 00/51] Large pages in the page cache Christoph Hellwig
2020-06-11 11:24   ` Matthew Wilcox
2020-06-15 13:32     ` Christoph Hellwig
2020-06-14 16:26 ` Matthew Wilcox

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