Commit 6dbd8224 authored by Steven Whitehouse's avatar Steven Whitehouse
Browse files

[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: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent ac39aadd

fs/gfs2/bmap.c

+2 −2
Original line number Diff line number Diff line
@@ -683,7 +683,7 @@ static int do_strip(struct gfs2_inode *ip, struct buffer_head *dibh, 
	if (metadata)

		revokes = (height) ? sdp->sd_inptrs : sdp->sd_diptrs;



	error = gfs2_rindex_hold(sdp, &ip->i_alloc.al_ri_gh);

	error = gfs2_rindex_hold(sdp, &ip->i_alloc->al_ri_gh);

	if (error)

		return error;
@@ -785,7 +785,7 @@ out_rg_gunlock: 
out_rlist:

	gfs2_rlist_free(&rlist);

out:

	gfs2_glock_dq_uninit(&ip->i_alloc.al_ri_gh);

	gfs2_glock_dq_uninit(&ip->i_alloc->al_ri_gh);

	return error;

}

fs/gfs2/dir.c

+2 −2
Original line number Diff line number Diff line
@@ -1876,7 +1876,7 @@ static int leaf_dealloc(struct gfs2_inode *dip, u32 index, u32 len, 
	if (error)

		goto out;



	error = gfs2_rindex_hold(sdp, &dip->i_alloc.al_ri_gh);

	error = gfs2_rindex_hold(sdp, &dip->i_alloc->al_ri_gh);

	if (error)

		goto out_qs;
@@ -1949,7 +1949,7 @@ out_rg_gunlock: 
	gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);

out_rlist:

	gfs2_rlist_free(&rlist);

	gfs2_glock_dq_uninit(&dip->i_alloc.al_ri_gh);

	gfs2_glock_dq_uninit(&dip->i_alloc->al_ri_gh);

out_qs:

	gfs2_quota_unhold(dip);

out:

fs/gfs2/eattr.c

+1 −1
Original line number Diff line number Diff line
@@ -1418,7 +1418,7 @@ out: 
static int ea_dealloc_block(struct gfs2_inode *ip)

{

	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

	struct gfs2_alloc *al = &ip->i_alloc;

	struct gfs2_alloc *al = ip->i_alloc;

	struct gfs2_rgrpd *rgd;

	struct buffer_head *dibh;

	int error;

fs/gfs2/incore.h

+1 −1
Original line number Diff line number Diff line
@@ -264,7 +264,7 @@ struct gfs2_inode { 
	struct gfs2_glock *i_gl; /* Move into i_gh? */

	struct gfs2_holder i_iopen_gh;

	struct gfs2_holder i_gh; /* for prepare/commit_write only */

	struct gfs2_alloc i_alloc;

	struct gfs2_alloc *i_alloc;

	u64 i_last_rg_alloc;



	spinlock_t i_spin;

fs/gfs2/inode.c

+4 −3
Original line number Diff line number Diff line
@@ -711,9 +711,10 @@ static int alloc_dinode(struct gfs2_inode *dip, u64 *no_addr, u64 *generation) 
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);

	int error;



	gfs2_alloc_get(dip);

	if (gfs2_alloc_get(dip) == NULL)

		return -ENOMEM;



	dip->i_alloc.al_requested = RES_DINODE;

	dip->i_alloc->al_requested = RES_DINODE;

	error = gfs2_inplace_reserve(dip);

	if (error)

		goto out;
@@ -900,7 +901,7 @@ fail_end_trans: 
	gfs2_trans_end(sdp);



fail_ipreserv:

	if (dip->i_alloc.al_rgd)

	if (dip->i_alloc->al_rgd)

		gfs2_inplace_release(dip);



fail_quota_locks:

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