This approach removes at least two indirect function calls from the
readahead path. Previous call chain (indirect function calls marked *):
xfs_vm_readahead
iomap_readahead
iomap_apply
xfs_read_iomap_begin [*]
iomap_readahead_actor [*]
iomap_readpage_actor
New call chain:
xfs_vm_readahead
xfs_iomap_next_read
iomi_advance
iomap_readahead
iomap_readpage_actor
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/iomap/buffered-io.c | 82 ++++++++++++++----------------------------
fs/xfs/xfs_aops.c | 9 ++++-
fs/xfs/xfs_iomap.c | 15 ++++++++
fs/xfs/xfs_iomap.h | 2 ++
fs/zonefs/super.c | 20 ++++++++++-
include/linux/iomap.h | 10 +++++-
6 files changed, 79 insertions(+), 59 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index bcfc288dba3f..fff23ed6a682 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -206,13 +206,6 @@ iomap_read_end_io(struct bio *bio)
bio_put(bio);
}
-struct iomap_readpage_ctx {
- struct page *cur_page;
- bool cur_page_in_bio;
- struct bio *bio;
- struct readahead_control *rac;
-};
-
static void
iomap_read_inline_data(struct inode *inode, struct page *page,
struct iomap *iomap)
@@ -369,35 +362,10 @@ iomap_readpage(struct page *page, const struct iomap_ops *ops)
}
EXPORT_SYMBOL_GPL(iomap_readpage);
-static loff_t
-iomap_readahead_actor(struct inode *inode, loff_t pos, loff_t length,
- void *data, struct iomap *iomap, struct iomap *srcmap)
-{
- struct iomap_readpage_ctx *ctx = data;
- loff_t done, ret;
-
- for (done = 0; done < length; done += ret) {
- if (ctx->cur_page && offset_in_page(pos + done) == 0) {
- if (!ctx->cur_page_in_bio)
- unlock_page(ctx->cur_page);
- put_page(ctx->cur_page);
- ctx->cur_page = NULL;
- }
- if (!ctx->cur_page) {
- ctx->cur_page = readahead_page(ctx->rac);
- ctx->cur_page_in_bio = false;
- }
- ret = iomap_readpage_actor(inode, pos + done, length - done,
- ctx, iomap, srcmap);
- }
-
- return done;
-}
-
/**
* iomap_readahead - Attempt to read pages from a file.
+ * @iomi: The iomap iterator for this operation.
* @rac: Describes the pages to be read.
- * @ops: The operations vector for the filesystem.
*
* This function is for filesystems to call to implement their readahead
* address_space operation.
@@ -409,35 +377,37 @@ iomap_readahead_actor(struct inode *inode, loff_t pos, loff_t length,
* function is called with memalloc_nofs set, so allocations will not cause
* the filesystem to be reentered.
*/
-void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
+loff_t iomap_readahead(struct iomap_iter *iomi, struct iomap_readpage_ctx *ctx)
{
- struct inode *inode = rac->mapping->host;
- loff_t pos = readahead_pos(rac);
- loff_t length = readahead_length(rac);
- struct iomap_readpage_ctx ctx = {
- .rac = rac,
- };
-
- trace_iomap_readahead(inode, readahead_count(rac));
+ loff_t done, ret, length = iomap_length(iomi);
- while (length > 0) {
- loff_t ret = iomap_apply(inode, pos, length, 0, ops,
- &ctx, iomap_readahead_actor);
- if (ret <= 0) {
- WARN_ON_ONCE(ret == 0);
- break;
+ for (done = 0; done < length; done += ret) {
+ if (ctx->cur_page && offset_in_page(iomi->pos + done) == 0) {
+ if (!ctx->cur_page_in_bio)
+ unlock_page(ctx->cur_page);
+ put_page(ctx->cur_page);
+ ctx->cur_page = NULL;
}
- pos += ret;
- length -= ret;
+ if (!ctx->cur_page) {
+ ctx->cur_page = readahead_page(ctx->rac);
+ ctx->cur_page_in_bio = false;
+ }
+ ret = iomap_readpage_actor(iomi->inode, iomi->pos + done,
+ length - done, ctx,
+ &iomi->iomap, &iomi->srcmap);
}
- if (ctx.bio)
- submit_bio(ctx.bio);
- if (ctx.cur_page) {
- if (!ctx.cur_page_in_bio)
- unlock_page(ctx.cur_page);
- put_page(ctx.cur_page);
+ if (iomi->len == done) {
+ if (ctx->bio)
+ submit_bio(ctx->bio);
+ if (ctx->cur_page) {
+ if (!ctx->cur_page_in_bio)
+ unlock_page(ctx->cur_page);
+ put_page(ctx->cur_page);
+ }
}
+
+ return done;
}
EXPORT_SYMBOL_GPL(iomap_readahead);
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index b35611882ff9..2884752e40e8 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -625,7 +625,14 @@ STATIC void
xfs_vm_readahead(
struct readahead_control *rac)
{
- iomap_readahead(rac, &xfs_read_iomap_ops);
+ IOMAP_ITER(iomi, rac->mapping->host, readahead_pos(rac),
+ readahead_length(rac), 0);
+ struct iomap_readpage_ctx ctx = {
+ .rac = rac,
+ };
+
+ while (iomap_iter(&iomi, xfs_iomap_next_read))
+ iomi.copied = iomap_readahead(&iomi, &ctx);
}
static int
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 0e3f62cde375..66f2fcaf136e 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1150,6 +1150,21 @@ const struct iomap_ops xfs_read_iomap_ops = {
.iomap_begin = xfs_read_iomap_begin,
};
+int
+xfs_iomap_next_read(
+ const struct iomap_iter *iomi,
+ struct iomap *iomap,
+ struct iomap *srcmap)
+{
+ if (iomi->copied < 0)
+ return iomi->copied;
+ if (iomi->copied >= iomi->len)
+ return 0;
+
+ return xfs_read_iomap_begin(iomi->inode, iomi->pos + iomi->copied,
+ iomi->len - iomi->copied, iomi->flags, iomap, srcmap);
+}
+
static int
xfs_seek_iomap_begin(
struct inode *inode,
diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index 7d3703556d0e..1b1fa225e938 100644
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -46,4 +46,6 @@ extern const struct iomap_ops xfs_read_iomap_ops;
extern const struct iomap_ops xfs_seek_iomap_ops;
extern const struct iomap_ops xfs_xattr_iomap_ops;
+int xfs_iomap_next_read(const struct iomap_iter *iomi, struct iomap *iomap,
+ struct iomap *srcmap);
#endif /* __XFS_IOMAP_H__*/
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index 07bc42d62673..4842b85ce36d 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -70,6 +70,17 @@ static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
return 0;
}
+static int zonefs_iomap_next(const struct iomap_iter *iomi,
+ struct iomap *iomap, struct iomap *srcmap)
+{
+ if (iomi->copied < 0)
+ return iomi->copied;
+ if (iomi->copied >= iomi->len)
+ return 0;
+ return zonefs_iomap_begin(iomi->inode, iomi->pos + iomi->copied,
+ iomi->len - iomi->copied, iomi->flags, iomap, srcmap);
+}
+
static const struct iomap_ops zonefs_iomap_ops = {
.iomap_begin = zonefs_iomap_begin,
};
@@ -81,7 +92,14 @@ static int zonefs_readpage(struct file *unused, struct page *page)
static void zonefs_readahead(struct readahead_control *rac)
{
- iomap_readahead(rac, &zonefs_iomap_ops);
+ IOMAP_ITER(iomi, rac->mapping->host, readahead_pos(rac),
+ readahead_length(rac), 0);
+ struct iomap_readpage_ctx ctx = {
+ .rac = rac,
+ };
+
+ while (iomap_iter(&iomi, zonefs_iomap_next))
+ iomi.copied = iomap_readahead(&iomi, &ctx);
}
/*
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index fe58e68ec0c1..dd9bfed85c4f 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -212,7 +212,6 @@ loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops);
int iomap_readpage(struct page *page, const struct iomap_ops *ops);
-void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
int iomap_set_page_dirty(struct page *page);
int iomap_is_partially_uptodate(struct page *page, unsigned long from,
unsigned long count);
@@ -299,6 +298,15 @@ int iomap_writepages(struct address_space *mapping,
struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
const struct iomap_writeback_ops *ops);
+struct iomap_readpage_ctx {
+ struct page *cur_page;
+ bool cur_page_in_bio;
+ struct bio *bio;
+ struct readahead_control *rac;
+};
+
+loff_t iomap_readahead(struct iomap_iter *, struct iomap_readpage_ctx *);
+
/*
* Flags for direct I/O ->end_io:
*/
--
2.27.0
