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authorAndreas Gruenbacher <agruenba@redhat.com>2015-11-13 07:44:57 -0600
committerBob Peterson <rpeterso@redhat.com>2015-11-18 14:51:50 -0600
commit39b0555f7a1f96ecd303103df15596db49c36c65 (patch)
tree558dd9324ec3996da145ddad3ec6b3a079bfb2a2
parentc8d577038449a718ad0027d1790b6ef4441715d4 (diff)
gfs2: Extended attribute readahead optimization
Instead of submitting a READ_SYNC bio for the inode and a READA bio for the inode's extended attributes through submit_bh, submit a single READ_SYNC bio for both through submit_bio when possible. This can be more efficient on some kinds of block devices. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
-rw-r--r--fs/gfs2/meta_io.c81
1 files changed, 63 insertions, 18 deletions
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 0f24828f8488..e137d96f1b17 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -187,19 +187,50 @@ struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
return bh;
}
-static void gfs2_meta_readahead(struct gfs2_glock *gl, u64 blkno)
+static void gfs2_meta_read_endio(struct bio *bio)
{
- struct buffer_head *bh;
+ struct bio_vec *bvec;
+ int i;
+
+ bio_for_each_segment_all(bvec, bio, i) {
+ struct page *page = bvec->bv_page;
+ struct buffer_head *bh = page_buffers(page);
+ unsigned int len = bvec->bv_len;
+
+ while (bh_offset(bh) < bvec->bv_offset)
+ bh = bh->b_this_page;
+ do {
+ struct buffer_head *next = bh->b_this_page;
+ len -= bh->b_size;
+ bh->b_end_io(bh, !bio->bi_error);
+ bh = next;
+ } while (bh && len);
+ }
+ bio_put(bio);
+}
- bh = gfs2_getbuf(gl, blkno, 1);
- lock_buffer(bh);
- if (buffer_uptodate(bh)) {
- unlock_buffer(bh);
- brelse(bh);
+/*
+ * Submit several consecutive buffer head I/O requests as a single bio I/O
+ * request. (See submit_bh_wbc.)
+ */
+static void gfs2_submit_bhs(int rw, struct buffer_head *bhs[], int num)
+{
+ struct buffer_head *bh = bhs[0];
+ struct bio *bio;
+ int i;
+
+ if (!num)
return;
+
+ bio = bio_alloc(GFP_NOIO, num);
+ bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
+ bio->bi_bdev = bh->b_bdev;
+ for (i = 0; i < num; i++) {
+ bh = bhs[i];
+ bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
}
- bh->b_end_io = end_buffer_read_sync;
- submit_bh(READA | REQ_META | REQ_PRIO, bh);
+ bio->bi_end_io = gfs2_meta_read_endio;
+ submit_bio(rw, bio);
}
/**
@@ -216,7 +247,8 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
int rahead, struct buffer_head **bhp)
{
struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
- struct buffer_head *bh;
+ struct buffer_head *bh, *bhs[2];
+ int num = 0;
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
*bhp = NULL;
@@ -228,18 +260,31 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
lock_buffer(bh);
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
- if (rahead)
- gfs2_meta_readahead(gl, blkno + 1);
- return 0;
+ flags &= ~DIO_WAIT;
+ } else {
+ bh->b_end_io = end_buffer_read_sync;
+ get_bh(bh);
+ bhs[num++] = bh;
}
- bh->b_end_io = end_buffer_read_sync;
- get_bh(bh);
- submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
- if (rahead)
- gfs2_meta_readahead(gl, blkno + 1);
+
+ if (rahead) {
+ bh = gfs2_getbuf(gl, blkno + 1, CREATE);
+
+ lock_buffer(bh);
+ if (buffer_uptodate(bh)) {
+ unlock_buffer(bh);
+ brelse(bh);
+ } else {
+ bh->b_end_io = end_buffer_read_sync;
+ bhs[num++] = bh;
+ }
+ }
+
+ gfs2_submit_bhs(READ_SYNC | REQ_META | REQ_PRIO, bhs, num);
if (!(flags & DIO_WAIT))
return 0;
+ bh = *bhp;
wait_on_buffer(bh);
if (unlikely(!buffer_uptodate(bh))) {
struct gfs2_trans *tr = current->journal_info;