Skip to content

Commit

Permalink
buffer: have alloc_page_buffers() use __GFP_NOFAIL
Browse files Browse the repository at this point in the history
Instead of adding weird retry logic in that function, utilize
__GFP_NOFAIL to ensure that the vm takes care of handling any
potential retries appropriately. This means we don't have to
call free_more_memory() from here.

Reviewed-by: Nikolay Borisov <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
  • Loading branch information
axboe committed Oct 3, 2017
1 parent 7beb2f8 commit 640ab98
Show file tree
Hide file tree
Showing 5 changed files with 14 additions and 27 deletions.
2 changes: 1 addition & 1 deletion drivers/md/bitmap.c
Original file line number Diff line number Diff line change
Expand Up @@ -368,7 +368,7 @@ static int read_page(struct file *file, unsigned long index,
pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT);

bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
bh = alloc_page_buffers(page, 1<<inode->i_blkbits, false);
if (!bh) {
ret = -ENOMEM;
goto out;
Expand Down
33 changes: 10 additions & 23 deletions fs/buffer.c
Original file line number Diff line number Diff line change
Expand Up @@ -861,16 +861,19 @@ int remove_inode_buffers(struct inode *inode)
* which may not fail from ordinary buffer allocations.
*/
struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
int retry)
bool retry)
{
struct buffer_head *bh, *head;
gfp_t gfp = GFP_NOFS;
long offset;

try_again:
if (retry)
gfp |= __GFP_NOFAIL;

head = NULL;
offset = PAGE_SIZE;
while ((offset -= size) >= 0) {
bh = alloc_buffer_head(GFP_NOFS);
bh = alloc_buffer_head(gfp);
if (!bh)
goto no_grow;

Expand All @@ -896,23 +899,7 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
} while (head);
}

/*
* Return failure for non-async IO requests. Async IO requests
* are not allowed to fail, so we have to wait until buffer heads
* become available. But we don't want tasks sleeping with
* partially complete buffers, so all were released above.
*/
if (!retry)
return NULL;

/* We're _really_ low on memory. Now we just
* wait for old buffer heads to become free due to
* finishing IO. Since this is an async request and
* the reserve list is empty, we're sure there are
* async buffer heads in use.
*/
free_more_memory();
goto try_again;
return NULL;
}
EXPORT_SYMBOL_GPL(alloc_page_buffers);

Expand Down Expand Up @@ -1021,7 +1008,7 @@ grow_dev_page(struct block_device *bdev, sector_t block,
/*
* Allocate some buffers for this page
*/
bh = alloc_page_buffers(page, size, 0);
bh = alloc_page_buffers(page, size, false);
if (!bh)
goto failed;

Expand Down Expand Up @@ -1575,7 +1562,7 @@ void create_empty_buffers(struct page *page,
{
struct buffer_head *bh, *head, *tail;

head = alloc_page_buffers(page, blocksize, 1);
head = alloc_page_buffers(page, blocksize, true);
bh = head;
do {
bh->b_state |= b_state;
Expand Down Expand Up @@ -2638,7 +2625,7 @@ int nobh_write_begin(struct address_space *mapping,
* Be careful: the buffer linked list is a NULL terminated one, rather
* than the circular one we're used to.
*/
head = alloc_page_buffers(page, blocksize, 0);
head = alloc_page_buffers(page, blocksize, false);
if (!head) {
ret = -ENOMEM;
goto out_release;
Expand Down
2 changes: 1 addition & 1 deletion fs/ntfs/aops.c
Original file line number Diff line number Diff line change
Expand Up @@ -1739,7 +1739,7 @@ void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
spin_lock(&mapping->private_lock);
if (unlikely(!page_has_buffers(page))) {
spin_unlock(&mapping->private_lock);
bh = head = alloc_page_buffers(page, bh_size, 1);
bh = head = alloc_page_buffers(page, bh_size, true);
spin_lock(&mapping->private_lock);
if (likely(!page_has_buffers(page))) {
struct buffer_head *tail;
Expand Down
2 changes: 1 addition & 1 deletion fs/ntfs/mft.c
Original file line number Diff line number Diff line change
Expand Up @@ -507,7 +507,7 @@ int ntfs_sync_mft_mirror(ntfs_volume *vol, const unsigned long mft_no,
if (unlikely(!page_has_buffers(page))) {
struct buffer_head *tail;

bh = head = alloc_page_buffers(page, blocksize, 1);
bh = head = alloc_page_buffers(page, blocksize, true);
do {
set_buffer_uptodate(bh);
tail = bh;
Expand Down
2 changes: 1 addition & 1 deletion include/linux/buffer_head.h
Original file line number Diff line number Diff line change
Expand Up @@ -156,7 +156,7 @@ void set_bh_page(struct buffer_head *bh,
struct page *page, unsigned long offset);
int try_to_free_buffers(struct page *);
struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
int retry);
bool retry);
void create_empty_buffers(struct page *, unsigned long,
unsigned long b_state);
void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
Expand Down

0 comments on commit 640ab98

Please sign in to comment.