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xfs: xfs_alloc_fix_freelist() can use incore perag structures 

At the moment, xfs_alloc_fix_freelist() uses a mix of per-ag based
access and agf buffer  based access to freelist and space usage
information. However, once the AGF buffer is locked inside this
function, it is guaranteed that both the in-memory and on-disk
values are identical. xfs_alloc_fix_freelist() doesn't modify the
values in the structures directly, so it is a read-only user of the
infomration, and hence can use the per-ag structure exclusively for
determining what it should do.

This opens up an avenue for cleaning up a lot of duplicated logic
whose only difference is the structure it gets the data from, and in
doing so removes a lot of needless byte swapping overhead when
fixing up the free list.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Dave Chinner 2015-06-22 10:04:31 +10:00 committed by Dave Chinner
parent 5ebe6afaf0
commit 50adbcb4c4
4 changed files with 37 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
fs/xfs/libxfs/xfs_alloc.c
View File

@ -1825,11 +1825,11 @@ xfs_alloc_compute_maxlevels(
xfs_extlen_t
xfs_alloc_longest_free_extent(
struct xfs_mount *mp,
struct xfs_perag *pag)
struct xfs_perag *pag,
xfs_extlen_t need)
{
xfs_extlen_t need, delta = 0;
xfs_extlen_t delta = 0;
need = XFS_MIN_FREELIST_PAG(pag, mp);
if (need > pag->pagf_flcount)
delta = need - pag->pagf_flcount;
@ -1848,10 +1848,8 @@ xfs_alloc_fix_freelist(
int flags) /* XFS_ALLOC_FLAG_... */
{
xfs_buf_t *agbp; /* agf buffer pointer */
xfs_agf_t *agf; /* a.g. freespace structure pointer */
xfs_buf_t *agflbp;/* agfl buffer pointer */
xfs_agblock_t bno; /* freelist block */
xfs_extlen_t delta; /* new blocks needed in freelist */
int error; /* error result code */
xfs_extlen_t longest;/* longest extent in allocation group */
xfs_mount_t *mp; /* file system mount point structure */
@ -1895,7 +1893,7 @@ xfs_alloc_fix_freelist(
* total blocks, reject it.
*/
need = XFS_MIN_FREELIST_PAG(pag, mp);
longest = xfs_alloc_longest_free_extent(mp, pag);
longest = xfs_alloc_longest_free_extent(mp, pag, need);
if ((args->minlen + args->alignment + args->minalignslop - 1) >
longest ||
((int)(pag->pagf_freeblks + pag->pagf_flcount -
@ -1922,25 +1920,16 @@ xfs_alloc_fix_freelist(
return 0;
}
}
/*
* Figure out how many blocks we should have in the freelist.
*/
agf = XFS_BUF_TO_AGF(agbp);
need = XFS_MIN_FREELIST(agf, mp);
/*
* If there isn't enough total or single-extent, reject it.
*/
/* If there isn't enough total space or single-extent, reject it. */
need = XFS_MIN_FREELIST_PAG(pag, mp);
if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
delta = need > be32_to_cpu(agf->agf_flcount) ?
(need - be32_to_cpu(agf->agf_flcount)) : 0;
longest = be32_to_cpu(agf->agf_longest);
longest = (longest > delta) ? (longest - delta) :
(be32_to_cpu(agf->agf_flcount) > 0 || longest > 0);
longest = xfs_alloc_longest_free_extent(mp, pag, need);
if ((args->minlen + args->alignment + args->minalignslop - 1) >
longest ||
((int)(be32_to_cpu(agf->agf_freeblks) +
be32_to_cpu(agf->agf_flcount) - need - args->total) <
(int)args->minleft)) {
((int)(pag->pagf_freeblks + pag->pagf_flcount -
need - args->total) < (int)args->minleft)) {
xfs_trans_brelse(tp, agbp);
args->agbp = NULL;
return 0;
@ -1948,21 +1937,25 @@ xfs_alloc_fix_freelist(
}
/*
* Make the freelist shorter if it's too long.
*
* XXX (dgc): When we have lots of free space, does this buy us
* anything other than extra overhead when we need to put more blocks
* back on the free list? Maybe we should only do this when space is
* getting low or the AGFL is more than half full?
*/
while (be32_to_cpu(agf->agf_flcount) > need) {
xfs_buf_t *bp;
while (pag->pagf_flcount > need) {
struct xfs_buf *bp;
error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
if (error)
return error;
if ((error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1)))
error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1);
if (error)
return error;
bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
xfs_trans_binval(tp, bp);
}
/*
* Initialize the args structure.
*/
memset(&targs, 0, sizeof(targs));
targs.tp = tp;
targs.mp = mp;
@ -1971,18 +1964,18 @@ xfs_alloc_fix_freelist(
targs.alignment = targs.minlen = targs.prod = targs.isfl = 1;
targs.type = XFS_ALLOCTYPE_THIS_AG;
targs.pag = pag;
if ((error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp)))
error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp);
if (error)
return error;
/*
* Make the freelist longer if it's too short.
*/
while (be32_to_cpu(agf->agf_flcount) < need) {
/* Make the freelist longer if it's too short. */
while (pag->pagf_flcount < need) {
targs.agbno = 0;
targs.maxlen = need - be32_to_cpu(agf->agf_flcount);
/*
* Allocate as many blocks as possible at once.
*/
if ((error = xfs_alloc_ag_vextent(&targs))) {
targs.maxlen = need - pag->pagf_flcount;
/* Allocate as many blocks as possible at once. */
error = xfs_alloc_ag_vextent(&targs);
if (error) {
xfs_trans_brelse(tp, agflbp);
return error;
}

8
fs/xfs/libxfs/xfs_alloc.h
View File

@ -128,12 +128,8 @@ typedef struct xfs_alloc_arg {
#define XFS_ALLOC_USERDATA 1 /* allocation is for user data*/
#define XFS_ALLOC_INITIAL_USER_DATA 2 /* special case start of file */
/*
* Find the length of the longest extent in an AG.
*/
xfs_extlen_t
xfs_alloc_longest_free_extent(struct xfs_mount *mp,
struct xfs_perag *pag);
xfs_extlen_t xfs_alloc_longest_free_extent(struct xfs_mount *mp,
struct xfs_perag *pag, xfs_extlen_t need);
/*
* Compute and fill in value of m_ag_maxlevels.

3
fs/xfs/libxfs/xfs_bmap.c
View File

@ -3507,7 +3507,8 @@ xfs_bmap_longest_free_extent(
}
}
longest = xfs_alloc_longest_free_extent(mp, pag);
longest = xfs_alloc_longest_free_extent(mp, pag,
XFS_MIN_FREELIST_PAG(pag, mp));
if (*blen < longest)
*blen = longest;

3
fs/xfs/xfs_filestream.c
View File

@ -196,7 +196,8 @@ xfs_filestream_pick_ag(
goto next_ag;
}
longest = xfs_alloc_longest_free_extent(mp, pag);
longest = xfs_alloc_longest_free_extent(mp, pag,
XFS_MIN_FREELIST_PAG(pag, mp));
if (((minlen && longest >= minlen) ||
(!minlen && pag->pagf_freeblks >= minfree)) &&
(!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||