Commit a19fb380 authored Mar 26, 2011 by Dave Chinner Committed by Dave Chinner Mar 26, 2011

vmap: flush vmap aliases when mapping fails



On 32 bit systems, vmalloc space is limited and XFS can chew through
it quickly as the vmalloc space is lazily freed. This can result in
failure to map buffers, even when there is apparently large amounts
of vmalloc space available. Hence, if we fail to map a buffer, purge
the aliases that have not yet been freed to hopefuly free up enough
vmalloc space to allow a retry to succeed.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>

parent 82878897

fs/xfs/linux-2.6/xfs_buf.c

+11 −3

Original line number	Diff line number	Diff line
		@@ -455,9 +455,17 @@ _xfs_buf_map_pages(
		bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
		bp->b_flags \|= XBF_MAPPED;
		} else if (flags & XBF_MAPPED) {
		int retried = 0;

		do {
		bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
		-1, PAGE_KERNEL);
		if (unlikely(bp->b_addr == NULL))
		if (bp->b_addr)
		break;
		vm_unmap_aliases();
		} while (retried++ <= 1);

		if (!bp->b_addr)
		return -ENOMEM;
		bp->b_addr += bp->b_offset;
		bp->b_flags \|= XBF_MAPPED;