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Message-ID: <YYGfUuItAyTNax5V@casper.infradead.org>
Date: Tue, 2 Nov 2021 20:28:02 +0000
From: Matthew Wilcox <willy@...radead.org>
To: Christoph Hellwig <hch@...radead.org>
Cc: "Darrick J. Wong" <djwong@...nel.org>, linux-xfs@...r.kernel.org,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-block@...r.kernel.org, Jens Axboe <axboe@...nel.dk>
Subject: Re: [PATCH 18/21] iomap: Convert iomap_add_to_ioend to take a folio
On Tue, Nov 02, 2021 at 12:26:42AM -0700, Christoph Hellwig wrote:
> Looking at the code not part of the context this looks fine. But I
> really wonder if this (and also the blocks change above) would be
> better off being split into separate, clearly documented patches.
How do these three patches look? I retained your R-b on all three since
I figured the one you offered below was good for all of them.
>From ab7cace8f325ca5cc1b1e62e6a8498c84738bc10 Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
Date: Tue, 2 Nov 2021 10:51:55 -0400
Subject: [PATCH 1/3] iomap: Simplify iomap_writepage_map()
Rename end_offset to end_pos and file_offset to pos to match the
rest of the file. Simplify the loop by calculating nblocks
up front instead of each time around the loop.
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Reviewed-by: Christoph Hellwig <hch@....de>
---
fs/iomap/buffered-io.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 8f47879f9f05..e32e3cb2cf86 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1296,37 +1296,36 @@ iomap_add_to_ioend(struct inode *inode, loff_t offset, struct page *page,
static int
iomap_writepage_map(struct iomap_writepage_ctx *wpc,
struct writeback_control *wbc, struct inode *inode,
- struct page *page, u64 end_offset)
+ struct page *page, loff_t end_pos)
{
struct folio *folio = page_folio(page);
struct iomap_page *iop = iomap_page_create(inode, folio);
struct iomap_ioend *ioend, *next;
unsigned len = i_blocksize(inode);
- u64 file_offset; /* file offset of page */
+ unsigned nblocks = i_blocks_per_folio(inode, folio);
+ loff_t pos = folio_pos(folio);
int error = 0, count = 0, i;
LIST_HEAD(submit_list);
WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) != 0);
/*
- * Walk through the page to find areas to write back. If we run off the
- * end of the current map or find the current map invalid, grab a new
- * one.
+ * Walk through the folio to find areas to write back. If we
+ * run off the end of the current map or find the current map
+ * invalid, grab a new one.
*/
- for (i = 0, file_offset = page_offset(page);
- i < (PAGE_SIZE >> inode->i_blkbits) && file_offset < end_offset;
- i++, file_offset += len) {
+ for (i = 0; i < nblocks && pos < end_pos; i++, pos += len) {
if (iop && !test_bit(i, iop->uptodate))
continue;
- error = wpc->ops->map_blocks(wpc, inode, file_offset);
+ error = wpc->ops->map_blocks(wpc, inode, pos);
if (error)
break;
if (WARN_ON_ONCE(wpc->iomap.type == IOMAP_INLINE))
continue;
if (wpc->iomap.type == IOMAP_HOLE)
continue;
- iomap_add_to_ioend(inode, file_offset, page, iop, wpc, wbc,
+ iomap_add_to_ioend(inode, pos, page, iop, wpc, wbc,
&submit_list);
count++;
}
@@ -1350,7 +1349,7 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
* now.
*/
if (wpc->ops->discard_folio)
- wpc->ops->discard_folio(page_folio(page), file_offset);
+ wpc->ops->discard_folio(folio, pos);
if (!count) {
ClearPageUptodate(page);
unlock_page(page);
--
2.33.0
>From 07c994353e357c3b4252595a80b86e8565deb09c Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
Date: Tue, 2 Nov 2021 11:41:16 -0400
Subject: [PATCH 2/3] iomap: Simplify iomap_do_writepage()
Rename end_offset to end_pos and offset_into_page to poff to match the
rest of the file. Simplify the handling of the last page straddling
i_size.
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Reviewed-by: Christoph Hellwig <hch@....de>
---
fs/iomap/buffered-io.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index e32e3cb2cf86..4f4f33849417 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1397,9 +1397,7 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
{
struct iomap_writepage_ctx *wpc = data;
struct inode *inode = page->mapping->host;
- pgoff_t end_index;
- u64 end_offset;
- loff_t offset;
+ loff_t end_pos, isize;
trace_iomap_writepage(inode, page_offset(page), PAGE_SIZE);
@@ -1430,11 +1428,9 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* | desired writeback range | see else |
* ---------------------------------^------------------|
*/
- offset = i_size_read(inode);
- end_index = offset >> PAGE_SHIFT;
- if (page->index < end_index)
- end_offset = (loff_t)(page->index + 1) << PAGE_SHIFT;
- else {
+ isize = i_size_read(inode);
+ end_pos = page_offset(page) + PAGE_SIZE;
+ if (end_pos - 1 >= isize) {
/*
* Check whether the page to write out is beyond or straddles
* i_size or not.
@@ -1446,7 +1442,8 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* | | Straddles |
* ---------------------------------^-----------|--------|
*/
- unsigned offset_into_page = offset & (PAGE_SIZE - 1);
+ size_t poff = offset_in_page(isize);
+ pgoff_t end_index = isize >> PAGE_SHIFT;
/*
* Skip the page if it's fully outside i_size, e.g. due to a
@@ -1466,7 +1463,7 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* offset is just equal to the EOF.
*/
if (page->index > end_index ||
- (page->index == end_index && offset_into_page == 0))
+ (page->index == end_index && poff == 0))
goto redirty;
/*
@@ -1477,13 +1474,13 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* memory is zeroed when mapped, and writes to that region are
* not written out to the file."
*/
- zero_user_segment(page, offset_into_page, PAGE_SIZE);
+ zero_user_segment(page, poff, PAGE_SIZE);
/* Adjust the end_offset to the end of file */
- end_offset = offset;
+ end_pos = isize;
}
- return iomap_writepage_map(wpc, wbc, inode, page, end_offset);
+ return iomap_writepage_map(wpc, wbc, inode, page, end_pos);
redirty:
redirty_page_for_writepage(wbc, page);
--
2.33.0
>From d5412657a503ae27efb5770fbc1c5c980180c9c4 Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
Date: Tue, 2 Nov 2021 12:45:12 -0400
Subject: [PATCH 3/3] iomap: Convert iomap_add_to_ioend to take a folio
We still iterate one block at a time, but now we call compound_head()
less often.
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Reviewed-by: Christoph Hellwig <hch@....de>
---
fs/iomap/buffered-io.c | 70 ++++++++++++++++++++----------------------
1 file changed, 34 insertions(+), 36 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 4f4f33849417..8908368abd49 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1252,29 +1252,29 @@ iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t offset,
* first; otherwise finish off the current ioend and start another.
*/
static void
-iomap_add_to_ioend(struct inode *inode, loff_t offset, struct page *page,
+iomap_add_to_ioend(struct inode *inode, loff_t pos, struct folio *folio,
struct iomap_page *iop, struct iomap_writepage_ctx *wpc,
struct writeback_control *wbc, struct list_head *iolist)
{
- sector_t sector = iomap_sector(&wpc->iomap, offset);
+ sector_t sector = iomap_sector(&wpc->iomap, pos);
unsigned len = i_blocksize(inode);
- unsigned poff = offset & (PAGE_SIZE - 1);
+ size_t poff = offset_in_folio(folio, pos);
- if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, offset, sector)) {
+ if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, pos, sector)) {
if (wpc->ioend)
list_add(&wpc->ioend->io_list, iolist);
- wpc->ioend = iomap_alloc_ioend(inode, wpc, offset, sector, wbc);
+ wpc->ioend = iomap_alloc_ioend(inode, wpc, pos, sector, wbc);
}
- if (bio_add_page(wpc->ioend->io_bio, page, len, poff) != len) {
+ if (!bio_add_folio(wpc->ioend->io_bio, folio, len, poff)) {
wpc->ioend->io_bio = iomap_chain_bio(wpc->ioend->io_bio);
- __bio_add_page(wpc->ioend->io_bio, page, len, poff);
+ bio_add_folio(wpc->ioend->io_bio, folio, len, poff);
}
if (iop)
atomic_add(len, &iop->write_bytes_pending);
wpc->ioend->io_size += len;
- wbc_account_cgroup_owner(wbc, page, len);
+ wbc_account_cgroup_owner(wbc, &folio->page, len);
}
/*
@@ -1296,9 +1296,8 @@ iomap_add_to_ioend(struct inode *inode, loff_t offset, struct page *page,
static int
iomap_writepage_map(struct iomap_writepage_ctx *wpc,
struct writeback_control *wbc, struct inode *inode,
- struct page *page, loff_t end_pos)
+ struct folio *folio, loff_t end_pos)
{
- struct folio *folio = page_folio(page);
struct iomap_page *iop = iomap_page_create(inode, folio);
struct iomap_ioend *ioend, *next;
unsigned len = i_blocksize(inode);
@@ -1325,15 +1324,15 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
continue;
if (wpc->iomap.type == IOMAP_HOLE)
continue;
- iomap_add_to_ioend(inode, pos, page, iop, wpc, wbc,
+ iomap_add_to_ioend(inode, pos, folio, iop, wpc, wbc,
&submit_list);
count++;
}
WARN_ON_ONCE(!wpc->ioend && !list_empty(&submit_list));
- WARN_ON_ONCE(!PageLocked(page));
- WARN_ON_ONCE(PageWriteback(page));
- WARN_ON_ONCE(PageDirty(page));
+ WARN_ON_ONCE(!folio_test_locked(folio));
+ WARN_ON_ONCE(folio_test_writeback(folio));
+ WARN_ON_ONCE(folio_test_dirty(folio));
/*
* We cannot cancel the ioend directly here on error. We may have
@@ -1351,14 +1350,14 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
if (wpc->ops->discard_folio)
wpc->ops->discard_folio(folio, pos);
if (!count) {
- ClearPageUptodate(page);
- unlock_page(page);
+ folio_clear_uptodate(folio);
+ folio_unlock(folio);
goto done;
}
}
- set_page_writeback(page);
- unlock_page(page);
+ folio_start_writeback(folio);
+ folio_unlock(folio);
/*
* Preserve the original error if there was one; catch
@@ -1379,9 +1378,9 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
* with a partial page truncate on a sub-page block sized filesystem.
*/
if (!count)
- end_page_writeback(page);
+ folio_end_writeback(folio);
done:
- mapping_set_error(page->mapping, error);
+ mapping_set_error(folio->mapping, error);
return error;
}
@@ -1395,14 +1394,15 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
static int
iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
{
+ struct folio *folio = page_folio(page);
struct iomap_writepage_ctx *wpc = data;
- struct inode *inode = page->mapping->host;
+ struct inode *inode = folio->mapping->host;
loff_t end_pos, isize;
- trace_iomap_writepage(inode, page_offset(page), PAGE_SIZE);
+ trace_iomap_writepage(inode, folio_pos(folio), folio_size(folio));
/*
- * Refuse to write the page out if we're called from reclaim context.
+ * Refuse to write the folio out if we're called from reclaim context.
*
* This avoids stack overflows when called from deeply used stacks in
* random callers for direct reclaim or memcg reclaim. We explicitly
@@ -1416,10 +1416,10 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
goto redirty;
/*
- * Is this page beyond the end of the file?
+ * Is this folio beyond the end of the file?
*
- * The page index is less than the end_index, adjust the end_offset
- * to the highest offset that this page should represent.
+ * The folio index is less than the end_index, adjust the end_pos
+ * to the highest offset that this folio should represent.
* -----------------------------------------------------
* | file mapping | <EOF> |
* -----------------------------------------------------
@@ -1429,7 +1429,7 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* ---------------------------------^------------------|
*/
isize = i_size_read(inode);
- end_pos = page_offset(page) + PAGE_SIZE;
+ end_pos = folio_pos(folio) + folio_size(folio);
if (end_pos - 1 >= isize) {
/*
* Check whether the page to write out is beyond or straddles
@@ -1442,7 +1442,7 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* | | Straddles |
* ---------------------------------^-----------|--------|
*/
- size_t poff = offset_in_page(isize);
+ size_t poff = offset_in_folio(folio, isize);
pgoff_t end_index = isize >> PAGE_SHIFT;
/*
@@ -1462,8 +1462,8 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* checking if the page is totally beyond i_size or if its
* offset is just equal to the EOF.
*/
- if (page->index > end_index ||
- (page->index == end_index && poff == 0))
+ if (folio->index > end_index ||
+ (folio->index == end_index && poff == 0))
goto redirty;
/*
@@ -1474,17 +1474,15 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
* memory is zeroed when mapped, and writes to that region are
* not written out to the file."
*/
- zero_user_segment(page, poff, PAGE_SIZE);
-
- /* Adjust the end_offset to the end of file */
+ zero_user_segment(&folio->page, poff, folio_size(folio));
end_pos = isize;
}
- return iomap_writepage_map(wpc, wbc, inode, page, end_pos);
+ return iomap_writepage_map(wpc, wbc, inode, folio, end_pos);
redirty:
- redirty_page_for_writepage(wbc, page);
- unlock_page(page);
+ folio_redirty_for_writepage(wbc, folio);
+ folio_unlock(folio);
return 0;
}
--
2.33.0
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