From 6dbd822487d0a9f14432cb4680415b80656b63a2 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Thu, 10 Jan 2008 15:18:55 +0000 Subject: [GFS2] Reduce inode size by moving i_alloc out of line It is possible to reduce the size of GFS2 inodes by taking the i_alloc structure out of the gfs2_inode. This patch allocates the i_alloc structure whenever its needed, and frees it afterward. This decreases the amount of low memory we use at the expense of requiring a memory allocation for each page or partial page that we write. A quick test with postmark shows that the overhead is not measurable and I also note that OCFS2 use the same approach. In the future I'd like to solve the problem by shrinking down the size of the members of the i_alloc structure, but for now, this reduces the immediate problem of using too much low-memory on x86 and doesn't add too much overhead. Signed-off-by: Steven Whitehouse --- fs/gfs2/ops_address.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'fs/gfs2/ops_address.c') diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c index 37406a379e7a..38dbe99a30ed 100644 --- a/fs/gfs2/ops_address.c +++ b/fs/gfs2/ops_address.c @@ -646,7 +646,6 @@ static int gfs2_write_begin(struct file *file, struct address_space *mapping, if (error) goto out_unlock; - ip->i_alloc.al_requested = 0; if (alloc_required) { al = gfs2_alloc_get(ip); @@ -823,7 +822,7 @@ static int gfs2_write_end(struct file *file, struct address_space *mapping, struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_sbd *sdp = GFS2_SB(inode); struct buffer_head *dibh; - struct gfs2_alloc *al = &ip->i_alloc; + struct gfs2_alloc *al = ip->i_alloc; struct gfs2_dinode *di; unsigned int from = pos & (PAGE_CACHE_SIZE - 1); unsigned int to = from + len; @@ -861,7 +860,7 @@ static int gfs2_write_end(struct file *file, struct address_space *mapping, brelse(dibh); gfs2_trans_end(sdp); failed: - if (al->al_requested) { + if (al) { gfs2_inplace_release(ip); gfs2_quota_unlock(ip); gfs2_alloc_put(ip); -- cgit v1.2.3