[RFC PATCH 4/7] mm: Pass readahead_control into page_cache_{sync,async}_readahead()

David Howells
2020-09-01T16:29:02Z

Pass struct readahead_control into the page_cache_{sync,async}_readahead()
functions in preparation for making do_sync_mmap_readahead() pass down an
RAC struct.

Signed-off-by: David Howells <dhowells@redhat.com>
---

fs/btrfs/free-space-cache.c | 7 ++++---
fs/btrfs/ioctl.c | 10 +++++++---
fs/btrfs/relocation.c | 14 ++++++++------
fs/btrfs/send.c | 15 +++++++++------
fs/ext4/dir.c | 12 +++++++-----
fs/f2fs/dir.c | 10 +++++++---
include/linux/pagemap.h | 8 +++-----
mm/filemap.c | 27 +++++++++++++++------------
mm/khugepaged.c | 6 +++---
mm/readahead.c | 40 ++++++++++++----------------------------
10 files changed, 75 insertions(+), 74 deletions(-)

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index dc82fd0c80cb..0ca9361acf30 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -286,16 +286,17 @@ int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
static void readahead_cache(struct inode *inode)
{
struct file_ra_state *ra;
- unsigned long last_index;
+
+ DEFINE_READAHEAD(rac, NULL, inode->i_mapping, 0);

ra = kzalloc(sizeof(*ra), GFP_NOFS);
if (!ra)
return;

file_ra_state_init(ra, inode->i_mapping);
- last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
+ rac._nr_pages = (i_size_read(inode) - 1) >> PAGE_SHIFT;

- page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
+ page_cache_sync_readahead(&rac, ra);

kfree(ra);
}
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index bd3511c5ca81..5025a6a800e9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1428,6 +1428,8 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
struct page **pages = NULL;
bool do_compress = range->flags & BTRFS_DEFRAG_RANGE_COMPRESS;

+ DEFINE_READAHEAD(rac, file, inode->i_mapping, 0);
+
if (isize == 0)
return 0;

@@ -1534,9 +1536,11 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,

if (i + cluster > ra_index) {
ra_index = max(i, ra_index);
- if (ra)
- page_cache_sync_readahead(inode->i_mapping, ra,
- file, ra_index, cluster);
+ if (ra) {
+ rac._index = ra_index;
+ rac._nr_pages = cluster;
+ page_cache_sync_readahead(&rac, ra);
+ }
ra_index += cluster;
}

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 4ba1ab9cc76d..1979803fd475 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2684,6 +2684,8 @@ static int relocate_file_extent_cluster(struct inode *inode,
int nr = 0;
int ret = 0;

+ DEFINE_READAHEAD(rac, NULL, inode->i_mapping, 0);
+
if (!cluster->nr)
return 0;

@@ -2712,9 +2714,9 @@ static int relocate_file_extent_cluster(struct inode *inode,

page = find_lock_page(inode->i_mapping, index);
if (!page) {
- page_cache_sync_readahead(inode->i_mapping,
- ra, NULL, index,
- last_index + 1 - index);
+ rac._index = index;
+ rac._nr_pages = last_index + 1 - index;
+ page_cache_sync_readahead(&rac, ra);
page = find_or_create_page(inode->i_mapping, index,
mask);
if (!page) {
@@ -2728,9 +2730,9 @@ static int relocate_file_extent_cluster(struct inode *inode,
}

if (PageReadahead(page)) {
- page_cache_async_readahead(inode->i_mapping,
- ra, NULL, page, index,
- last_index + 1 - index);
+ rac._index = index;
+ rac._nr_pages = last_index + 1 - index;
+ page_cache_async_readahead(&rac, ra, page);
}

if (!PageUptodate(page)) {
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index d9813a5b075a..ee0a9a2b5d08 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4811,6 +4811,8 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
unsigned pg_offset = offset_in_page(offset);
ssize_t ret = 0;

+ DEFINE_READAHEAD(rac, NULL, NULL, 0);
+
inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root);
if (IS_ERR(inode))
return PTR_ERR(inode);
@@ -4829,15 +4831,18 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
/* initial readahead */
memset(&sctx->ra, 0, sizeof(struct file_ra_state));
file_ra_state_init(&sctx->ra, inode->i_mapping);
+ rac.mapping = inode->i_mapping;

while (index <= last_index) {
unsigned cur_len = min_t(unsigned, len,
PAGE_SIZE - pg_offset);

+ rac._index = index;
+ rac._nr_pages = last_index + 1 - index;
+
page = find_lock_page(inode->i_mapping, index);
if (!page) {
- page_cache_sync_readahead(inode->i_mapping, &sctx->ra,
- NULL, index, last_index + 1 - index);
+ page_cache_sync_readahead(&rac, &sctx->ra);

page = find_or_create_page(inode->i_mapping, index,
GFP_KERNEL);
@@ -4847,10 +4852,8 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
}
}

- if (PageReadahead(page)) {
- page_cache_async_readahead(inode->i_mapping, &sctx->ra,
- NULL, page, index, last_index + 1 - index);
- }
+ if (PageReadahead(page))
+ page_cache_async_readahead(&rac, &sctx->ra, page);

if (!PageUptodate(page)) {
btrfs_readpage(NULL, page);
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 1d82336b1cd4..6205c6830454 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -118,6 +118,8 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
struct buffer_head *bh = NULL;
struct fscrypt_str fstr = FSTR_INIT(NULL, 0);

+ DEFINE_READAHEAD(rac, file, sb->s_bdev->bd_inode->i_mapping, 0);
+
if (IS_ENCRYPTED(inode)) {
err = fscrypt_get_encryption_info(inode);
if (err)
@@ -176,11 +178,11 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
if (err > 0) {
pgoff_t index = map.m_pblk >>
(PAGE_SHIFT - inode->i_blkbits);
- if (!ra_has_index(&file->f_ra, index))
- page_cache_sync_readahead(
- sb->s_bdev->bd_inode->i_mapping,
- &file->f_ra, file,
- index, 1);
+ if (!ra_has_index(&file->f_ra, index)) {
+ rac._index = index;
+ rac._nr_pages = 1;
+ page_cache_sync_readahead(&rac, &file->f_ra);
+ }
file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
bh = ext4_bread(NULL, inode, map.m_lblk, 0);
if (IS_ERR(bh)) {
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 069f498af1e3..982f6d37454a 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -1027,6 +1027,8 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
int err = 0;

+ DEFINE_READAHEAD(rac, file, inode->i_mapping, 0);
+
if (IS_ENCRYPTED(inode)) {
err = fscrypt_get_encryption_info(inode);
if (err)
@@ -1052,9 +1054,11 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
cond_resched();

/* readahead for multi pages of dir */
- if (npages - n > 1 && !ra_has_index(ra, n))
- page_cache_sync_readahead(inode->i_mapping, ra, file, n,
- min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES));
+ if (npages - n > 1 && !ra_has_index(ra, n)) {
+ rac._index = n;
+ rac._nr_pages = min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES);
+ page_cache_sync_readahead(&rac, ra);
+ }

dentry_page = f2fs_find_data_page(inode, n);
if (IS_ERR(dentry_page)) {
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 8bf048a76c43..cd7bde29d4cc 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -769,11 +769,9 @@ void delete_from_page_cache_batch(struct address_space *mapping,

#define VM_READAHEAD_PAGES (SZ_128K / PAGE_SIZE)

-void page_cache_sync_readahead(struct address_space *, struct file_ra_state *,
- struct file *, pgoff_t index, unsigned long req_count);
-void page_cache_async_readahead(struct address_space *, struct file_ra_state *,
- struct file *, struct page *, pgoff_t index,
- unsigned long req_count);
+void page_cache_sync_readahead(struct readahead_control *, struct file_ra_state *);
+void page_cache_async_readahead(struct readahead_control *, struct file_ra_state *,
+ struct page *);
void page_cache_readahead_unbounded(struct readahead_control *,
unsigned long nr_to_read, unsigned long lookahead_count);

diff --git a/mm/filemap.c b/mm/filemap.c
index 82b97cf4306c..9f2f99db7318 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2070,6 +2070,8 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
unsigned int prev_offset;
int error = 0;

+ DEFINE_READAHEAD(rac, filp, mapping, 0);
+
if (unlikely(*ppos >= inode->i_sb->s_maxbytes))
return 0;
iov_iter_truncate(iter, inode->i_sb->s_maxbytes);
@@ -2097,9 +2099,9 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
if (!page) {
if (iocb->ki_flags & IOCB_NOIO)
goto would_block;
- page_cache_sync_readahead(mapping,
- ra, filp,
- index, last_index - index);
+ rac._index = index;
+ rac._nr_pages = last_index - index;
+ page_cache_sync_readahead(&rac, ra);
page = find_get_page(mapping, index);
if (unlikely(page == NULL))
goto no_cached_page;
@@ -2109,9 +2111,9 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
put_page(page);
goto out;
}
- page_cache_async_readahead(mapping,
- ra, filp, thp_head(page),
- index, last_index - index);
+ rac._index = index;
+ rac._nr_pages = last_index - index;
+ page_cache_async_readahead(&rac, ra, thp_head(page));
}
if (!PageUptodate(page)) {
/*
@@ -2469,6 +2471,8 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf)
pgoff_t offset = vmf->pgoff;
unsigned int mmap_miss;

+ DEFINE_READAHEAD(rac, file, mapping, offset);
+
/* If we don't want any read-ahead, don't bother */
if (vmf->vma->vm_flags & VM_RAND_READ)
return fpin;
@@ -2477,8 +2481,8 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf)

if (vmf->vma->vm_flags & VM_SEQ_READ) {
fpin = maybe_unlock_mmap_for_io(vmf, fpin);
- page_cache_sync_readahead(mapping, ra, file, offset,
- ra->ra_pages);
+ rac._nr_pages = ra->ra_pages;
+ page_cache_sync_readahead(&rac, ra);
return fpin;
}

@@ -2515,10 +2519,10 @@ static struct file *do_async_mmap_readahead(struct vm_fault *vmf,
{
struct file *file = vmf->vma->vm_file;
struct file_ra_state *ra = &file->f_ra;
- struct address_space *mapping = file->f_mapping;
struct file *fpin = NULL;
unsigned int mmap_miss;
- pgoff_t offset = vmf->pgoff;
+
+ DEFINE_READAHEAD(rac, file, file->f_mapping, vmf->pgoff);

/* If we don't want any read-ahead, don't bother */
if (vmf->vma->vm_flags & VM_RAND_READ || !ra->ra_pages)
@@ -2528,8 +2532,7 @@ static struct file *do_async_mmap_readahead(struct vm_fault *vmf,
WRITE_ONCE(ra->mmap_miss, --mmap_miss);
if (PageReadahead(thp_head(page))) {
fpin = maybe_unlock_mmap_for_io(vmf, fpin);
- page_cache_async_readahead(mapping, ra, file,
- thp_head(page), offset, ra->ra_pages);
+ page_cache_async_readahead(&rac, ra, thp_head(page));
}
return fpin;
}
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index f2d243077b74..0bece7ab0ce7 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1703,10 +1703,10 @@ static void collapse_file(struct mm_struct *mm,
}
} else { /* !is_shmem */
if (!page || xa_is_value(page)) {
+ DEFINE_READAHEAD(rac, file, mapping, index);
+ rac._nr_pages = end - index;
xas_unlock_irq(&xas);
- page_cache_sync_readahead(mapping, &file->f_ra,
- file, index,
- end - index);
+ page_cache_sync_readahead(&rac, &file->f_ra);
/* drain pagevecs to help isolate_lru_page() */
lru_add_drain();
page = find_lock_page(mapping, index);
diff --git a/mm/readahead.c b/mm/readahead.c
index e557c6d5a183..7114246b4e41 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -635,24 +635,17 @@ static void ondemand_readahead(struct readahead_control *rac,

/**
* page_cache_sync_readahead - generic file readahead
- * @mapping: address_space which holds the pagecache and I/O vectors
+ * @rac: Readahead control.
* @ra: file_ra_state which holds the readahead state
- * @filp: passed on to ->readpage() and ->readpages()
- * @index: Index of first page to be read.
- * @req_count: Total number of pages being read by the caller.
*
* page_cache_sync_readahead() should be called when a cache miss happened:
* it will submit the read. The readahead logic may decide to piggyback more
* pages onto the read request if access patterns suggest it will improve
* performance.
*/
-void page_cache_sync_readahead(struct address_space *mapping,
- struct file_ra_state *ra, struct file *filp,
- pgoff_t index, unsigned long req_count)
+void page_cache_sync_readahead(struct readahead_control *rac,
+ struct file_ra_state *ra)
{
- DEFINE_READAHEAD(rac, filp, mapping, index);
- rac._nr_pages = req_count;
-
/* no read-ahead */
if (!ra->ra_pages)
return;
@@ -661,39 +654,30 @@ void page_cache_sync_readahead(struct address_space *mapping,
return;

/* be dumb */
- if (filp && (filp->f_mode & FMODE_RANDOM)) {
- force_page_cache_readahead(&rac);
+ if (rac->file && (rac->file->f_mode & FMODE_RANDOM)) {
+ force_page_cache_readahead(rac);
return;
}

/* do read-ahead */
- ondemand_readahead(&rac, ra, NULL);
+ ondemand_readahead(rac, ra, NULL);
}
EXPORT_SYMBOL_GPL(page_cache_sync_readahead);

/**
* page_cache_async_readahead - file readahead for marked pages
- * @mapping: address_space which holds the pagecache and I/O vectors
+ * @rac: Readahead control.
* @ra: file_ra_state which holds the readahead state
- * @filp: passed on to ->readpage() and ->readpages()
- * @page: The page at @index which triggered the readahead call.
- * @index: Index of first page to be read.
- * @req_count: Total number of pages being read by the caller.
*
* page_cache_async_readahead() should be called when a page is used which
* is marked as PageReadahead; this is a marker to suggest that the application
* has used up enough of the readahead window that we should start pulling in
* more pages.
*/
-void
-page_cache_async_readahead(struct address_space *mapping,
- struct file_ra_state *ra, struct file *filp,
- struct page *page, pgoff_t index,
- unsigned long req_count)
+void page_cache_async_readahead(struct readahead_control *rac,
+ struct file_ra_state *ra,
+ struct page *page)
{
- DEFINE_READAHEAD(rac, filp, mapping, index);
- rac._nr_pages = req_count;
-
/* No Read-ahead */
if (!ra->ra_pages)
return;
@@ -709,14 +693,14 @@ page_cache_async_readahead(struct address_space *mapping,
/*
* Defer asynchronous read-ahead on IO congestion.
*/
- if (inode_read_congested(mapping->host))
+ if (inode_read_congested(rac->mapping->host))
return;

if (blk_cgroup_congested())
return;

/* do read-ahead */
- ondemand_readahead(&rac, ra, page);
+ ondemand_readahead(rac, ra, page);
}
EXPORT_SYMBOL_GPL(page_cache_async_readahead);