Commit c9fa5630 authored by Dave Chinner's avatar Dave Chinner Committed by Dave Chinner
Browse files

xfs: use alloc_pages_bulk_array() for buffers 



Because it's more efficient than allocating pages one at a time in a
loop.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
parent 07b5c5ad

fs/xfs/xfs_buf.c

+24 −38
Original line number Diff line number Diff line
@@ -386,10 +386,7 @@ xfs_buf_alloc_pages( 
	xfs_buf_flags_t	flags)

{

	gfp_t		gfp_mask = xb_to_gfp(flags);

	size_t		size;

	size_t		offset;

	size_t		nbytes;

	int		i;

	long		filled = 0;

	int		error;



	/* Assure zeroed buffer for non-read cases. */
@@ -400,50 +397,39 @@ xfs_buf_alloc_pages( 
	if (unlikely(error))

		return error;



	offset = bp->b_offset;

	bp->b_flags |= _XBF_PAGES;



	for (i = 0; i < bp->b_page_count; i++) {

		struct page	*page;

		uint		retries = 0;

retry:

		page = alloc_page(gfp_mask);

		if (unlikely(page == NULL)) {

	/*

	 * Bulk filling of pages can take multiple calls. Not filling the entire

	 * array is not an allocation failure, so don't back off if we get at

	 * least one extra page.

	 */

	for (;;) {

		long	last = filled;



		filled = alloc_pages_bulk_array(gfp_mask, bp->b_page_count,

						bp->b_pages);

		if (filled == bp->b_page_count) {

			XFS_STATS_INC(bp->b_mount, xb_page_found);

			break;

		}



		if (filled != last)

			continue;



		if (flags & XBF_READ_AHEAD) {

				bp->b_page_count = i;

			error = -ENOMEM;

			goto out_free_pages;

		}



			/*

			 * This could deadlock.

			 *

			 * But until all the XFS lowlevel code is revamped to

			 * handle buffer allocation failures we can't do much.

			 */

			if (!(++retries % 100))

				xfs_err(NULL,

		"%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",

					current->comm, current->pid,

					__func__, gfp_mask);



		XFS_STATS_INC(bp->b_mount, xb_page_retries);

		congestion_wait(BLK_RW_ASYNC, HZ / 50);

			goto retry;

		}



		XFS_STATS_INC(bp->b_mount, xb_page_found);



		nbytes = min_t(size_t, size, PAGE_SIZE - offset);

		size -= nbytes;

		bp->b_pages[i] = page;

		offset = 0;

	}

	return 0;



out_free_pages:

	for (i = 0; i < bp->b_page_count; i++)

		__free_page(bp->b_pages[i]);

	while (--filled >= 0)

		__free_page(bp->b_pages[filled]);

	bp->b_flags &= ~_XBF_PAGES;

	return error;

}