[XFS] cluster rewrites We can cluster mapped pages aswell, this improves
performances on rewrites since we can reduce the number of allocator
calls.
SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203829a
Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 5628673..9ea33ea 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -470,13 +470,13 @@
}
/*
- * Look for a page at index which is unlocked and not mapped
- * yet - clustering for mmap write case.
+ * Look for a page at index that is suitable for clustering.
*/
STATIC unsigned int
-xfs_probe_unmapped_page(
+xfs_probe_page(
struct page *page,
- unsigned int pg_offset)
+ unsigned int pg_offset,
+ int mapped)
{
int ret = 0;
@@ -489,25 +489,28 @@
bh = head = page_buffers(page);
do {
- if (buffer_mapped(bh) || !buffer_uptodate(bh))
+ if (!buffer_uptodate(bh))
+ break;
+ if (mapped != buffer_mapped(bh))
break;
ret += bh->b_size;
if (ret >= pg_offset)
break;
} while ((bh = bh->b_this_page) != head);
} else
- ret = PAGE_CACHE_SIZE;
+ ret = mapped ? 0 : PAGE_CACHE_SIZE;
}
return ret;
}
STATIC size_t
-xfs_probe_unmapped_cluster(
+xfs_probe_cluster(
struct inode *inode,
struct page *startpage,
struct buffer_head *bh,
- struct buffer_head *head)
+ struct buffer_head *head,
+ int mapped)
{
struct pagevec pvec;
pgoff_t tindex, tlast, tloff;
@@ -516,7 +519,7 @@
/* First sum forwards in this page */
do {
- if (buffer_mapped(bh))
+ if (mapped != buffer_mapped(bh))
return total;
total += bh->b_size;
} while ((bh = bh->b_this_page) != head);
@@ -550,7 +553,7 @@
pg_offset = PAGE_CACHE_SIZE;
if (page->index == tindex && !TestSetPageLocked(page)) {
- len = xfs_probe_unmapped_page(page, pg_offset);
+ len = xfs_probe_page(page, pg_offset, mapped);
unlock_page(page);
}
@@ -592,6 +595,8 @@
acceptable = (type == IOMAP_UNWRITTEN);
else if (buffer_delay(bh))
acceptable = (type == IOMAP_DELAY);
+ else if (buffer_mapped(bh))
+ acceptable = (type == 0);
else
break;
} while ((bh = bh->b_this_page) != head);
@@ -804,6 +809,7 @@
ssize_t size, len;
int flags, err, iomap_valid = 0, uptodate = 1;
int page_dirty, count = 0, trylock_flag = 0;
+ int all_bh = unmapped;
/* wait for other IO threads? */
if (startio && wbc->sync_mode != WB_SYNC_NONE)
@@ -845,6 +851,8 @@
bh = head = page_buffers(page);
offset = page_offset(page);
+ flags = -1;
+ type = 0;
/* TODO: cleanup count and page_dirty */
@@ -878,6 +886,12 @@
if (buffer_unwritten(bh) || buffer_delay(bh) ||
((buffer_uptodate(bh) || PageUptodate(page)) &&
!buffer_mapped(bh) && (unmapped || startio))) {
+ /*
+ * Make sure we don't use a read-only iomap
+ */
+ if (flags == BMAPI_READ)
+ iomap_valid = 0;
+
if (buffer_unwritten(bh)) {
type = IOMAP_UNWRITTEN;
flags = BMAPI_WRITE|BMAPI_IGNSTATE;
@@ -887,14 +901,14 @@
if (!startio)
flags |= trylock_flag;
} else {
- type = 0;
+ type = IOMAP_NEW;
flags = BMAPI_WRITE|BMAPI_MMAP;
}
if (!iomap_valid) {
- if (type == 0) {
- size = xfs_probe_unmapped_cluster(inode,
- page, bh, head);
+ if (type == IOMAP_NEW) {
+ size = xfs_probe_cluster(inode,
+ page, bh, head, 0);
} else {
size = len;
}
@@ -921,10 +935,27 @@
count++;
}
} else if (buffer_uptodate(bh) && startio) {
- type = 0;
+ /*
+ * we got here because the buffer is already mapped.
+ * That means it must already have extents allocated
+ * underneath it. Map the extent by reading it.
+ */
+ if (!iomap_valid || type != 0) {
+ flags = BMAPI_READ;
+ size = xfs_probe_cluster(inode, page, bh,
+ head, 1);
+ err = xfs_map_blocks(inode, offset, size,
+ &iomap, flags);
+ if (err)
+ goto error;
+ iomap_valid = xfs_iomap_valid(&iomap, offset);
+ }
+ type = 0;
if (!test_and_set_bit(BH_Lock, &bh->b_state)) {
ASSERT(buffer_mapped(bh));
+ if (iomap_valid)
+ all_bh = 1;
xfs_add_to_ioend(inode, bh, offset, type,
&ioend, !iomap_valid);
page_dirty--;
@@ -953,7 +984,7 @@
PAGE_CACHE_SHIFT;
tlast = min_t(pgoff_t, offset, last_index);
xfs_cluster_write(inode, page->index + 1, &iomap, &ioend,
- wbc, startio, unmapped, tlast);
+ wbc, startio, all_bh, tlast);
}
if (iohead)