xfs: get rid of unnecessary xfs_perag_{get,put} pairs

In the course of some operations, we look up the perag from
the mount multiple times to get or change perag information.
These are often very short pieces of code, so while the
lookup cost is generally low, the cost of the lookup is far
higher than the cost of the operation we are doing on the
perag.

Since we changed buffers to hold references to the perag
they are cached in, many modification contexts already hold
active references to the perag that are held across these
operations. This is especially true for any operation that
is serialised by an allocation group header buffer.

In these cases, we can just use the buffer's reference to
the perag to avoid needing to do lookups to access the
perag. This means that many operations don't need to do
perag lookups at all to access the perag because they've
already looked up objects that own persistent references
and hence can use that reference instead.

Cc: Dave Chinner <dchinner@redhat.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index 9d84007..8cf73fe 100644 (file)
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -563,7 +563,8 @@ xfs_ag_get_geometry(
        error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
        if (error)
                goto out_agi;
-       pag = xfs_perag_get(mp, agno);
+
+       pag = agi_bp->b_pag;
 
        /* Fill out form. */
        memset(ageo, 0, sizeof(*ageo));
@@ -583,7 +584,6 @@ xfs_ag_get_geometry(
        xfs_ag_geom_health(pag, ageo);
 
        /* Release resources. */
-       xfs_perag_put(pag);
        xfs_buf_relse(agf_bp);
 out_agi:
        xfs_buf_relse(agi_bp);

diff --git a/fs/xfs/libxfs/xfs_ag_resv.h b/fs/xfs/libxfs/xfs_ag_resv.h
index f3fd0ee..8a8eb4b 100644 (file)
--- a/fs/xfs/libxfs/xfs_ag_resv.h
+++ b/fs/xfs/libxfs/xfs_ag_resv.h
@@ -37,16 +37,4 @@ xfs_ag_resv_rmapbt_alloc(
        xfs_perag_put(pag);
 }
 
-static inline void
-xfs_ag_resv_rmapbt_free(
-       struct xfs_mount        *mp,
-       xfs_agnumber_t          agno)
-{
-       struct xfs_perag        *pag;
-
-       pag = xfs_perag_get(mp, agno);
-       xfs_ag_resv_free_extent(pag, XFS_AG_RESV_RMAPBT, NULL, 1);
-       xfs_perag_put(pag);
-}
-
 #endif /* __XFS_AG_RESV_H__ */

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 203e74f..bf4d07e 100644 (file)
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -710,13 +710,12 @@ xfs_alloc_read_agfl(
 STATIC int
 xfs_alloc_update_counters(
        struct xfs_trans        *tp,
-       struct xfs_perag        *pag,
        struct xfs_buf          *agbp,
        long                    len)
 {
        struct xfs_agf          *agf = agbp->b_addr;
 
-       pag->pagf_freeblks += len;
+       agbp->b_pag->pagf_freeblks += len;
        be32_add_cpu(&agf->agf_freeblks, len);
 
        xfs_trans_agblocks_delta(tp, len);
@@ -1175,8 +1174,7 @@ xfs_alloc_ag_vextent(
        }
 
        if (!args->wasfromfl) {
-               error = xfs_alloc_update_counters(args->tp, args->pag,
-                                                 args->agbp,
+               error = xfs_alloc_update_counters(args->tp, args->agbp,
                                                  -((long)(args->len)));
                if (error)
                        return error;
@@ -1887,7 +1885,6 @@ xfs_free_ag_extent(
        enum xfs_ag_resv_type           type)
 {
        struct xfs_mount                *mp;
-       struct xfs_perag                *pag;
        struct xfs_btree_cur            *bno_cur;
        struct xfs_btree_cur            *cnt_cur;
        xfs_agblock_t                   gtbno; /* start of right neighbor */
@@ -2167,10 +2164,8 @@ xfs_free_ag_extent(
        /*
         * Update the freespace totals in the ag and superblock.
         */
-       pag = xfs_perag_get(mp, agno);
-       error = xfs_alloc_update_counters(tp, pag, agbp, len);
-       xfs_ag_resv_free_extent(pag, type, tp, len);
-       xfs_perag_put(pag);
+       error = xfs_alloc_update_counters(tp, agbp, len);
+       xfs_ag_resv_free_extent(agbp->b_pag, type, tp, len);
        if (error)
                goto error0;
 
@@ -2689,7 +2684,7 @@ xfs_alloc_get_freelist(
        if (be32_to_cpu(agf->agf_flfirst) == xfs_agfl_size(mp))
                agf->agf_flfirst = 0;
 
-       pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
+       pag = agbp->b_pag;
        ASSERT(!pag->pagf_agflreset);
        be32_add_cpu(&agf->agf_flcount, -1);
        xfs_trans_agflist_delta(tp, -1);
@@ -2701,7 +2696,6 @@ xfs_alloc_get_freelist(
                pag->pagf_btreeblks++;
                logflags |= XFS_AGF_BTREEBLKS;
        }
-       xfs_perag_put(pag);
 
        xfs_alloc_log_agf(tp, agbp, logflags);
        *bnop = bno;
@@ -2797,7 +2791,7 @@ xfs_alloc_put_freelist(
        if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp))
                agf->agf_fllast = 0;
 
-       pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
+       pag = agbp->b_pag;
        ASSERT(!pag->pagf_agflreset);
        be32_add_cpu(&agf->agf_flcount, 1);
        xfs_trans_agflist_delta(tp, 1);
@@ -2809,7 +2803,6 @@ xfs_alloc_put_freelist(
                pag->pagf_btreeblks--;
                logflags |= XFS_AGF_BTREEBLKS;
        }
-       xfs_perag_put(pag);
 
        xfs_alloc_log_agf(tp, agbp, logflags);
 
@@ -3006,7 +2999,7 @@ xfs_alloc_read_agf(
        ASSERT(!(*bpp)->b_error);
 
        agf = (*bpp)->b_addr;
-       pag = xfs_perag_get(mp, agno);
+       pag = (*bpp)->b_pag;
        if (!pag->pagf_init) {
                pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
                pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
@@ -3034,7 +3027,6 @@ xfs_alloc_read_agf(
                       be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
        }
 #endif
-       xfs_perag_put(pag);
        return 0;
 }
 

diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index 60c453c..3d1226a 100644 (file)
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -38,16 +38,14 @@ xfs_allocbt_set_root(
 {
        struct xfs_buf          *agbp = cur->bc_ag.agbp;
        struct xfs_agf          *agf = agbp->b_addr;
-       xfs_agnumber_t          seqno = be32_to_cpu(agf->agf_seqno);
        int                     btnum = cur->bc_btnum;
-       struct xfs_perag        *pag = xfs_perag_get(cur->bc_mp, seqno);
+       struct xfs_perag        *pag = agbp->b_pag;
 
        ASSERT(ptr->s != 0);
 
        agf->agf_roots[btnum] = ptr->s;
        be32_add_cpu(&agf->agf_levels[btnum], inc);
        pag->pagf_levels[btnum] += inc;
-       xfs_perag_put(pag);
 
        xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
 }
@@ -115,7 +113,6 @@ xfs_allocbt_update_lastrec(
        int                     reason)
 {
        struct xfs_agf          *agf = cur->bc_ag.agbp->b_addr;
-       xfs_agnumber_t          seqno = be32_to_cpu(agf->agf_seqno);
        struct xfs_perag        *pag;
        __be32                  len;
        int                     numrecs;
@@ -160,9 +157,8 @@ xfs_allocbt_update_lastrec(
        }
 
        agf->agf_longest = len;
-       pag = xfs_perag_get(cur->bc_mp, seqno);
+       pag = cur->bc_ag.agbp->b_pag;
        pag->pagf_longest = be32_to_cpu(len);
-       xfs_perag_put(pag);
        xfs_alloc_log_agf(cur->bc_tp, cur->bc_ag.agbp, XFS_AGF_LONGEST);
 }
 

diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 7fcf62b..f742a96 100644 (file)
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -888,10 +888,9 @@ sparse_alloc:
         */
        be32_add_cpu(&agi->agi_count, newlen);
        be32_add_cpu(&agi->agi_freecount, newlen);
-       pag = xfs_perag_get(args.mp, agno);
+       pag = agbp->b_pag;
        pag->pagi_freecount += newlen;
        pag->pagi_count += newlen;
-       xfs_perag_put(pag);
        agi->agi_newino = cpu_to_be32(newino);
 
        /*
@@ -1134,7 +1133,7 @@ xfs_dialloc_ag_inobt(
        xfs_agnumber_t          agno = be32_to_cpu(agi->agi_seqno);
        xfs_agnumber_t          pagno = XFS_INO_TO_AGNO(mp, parent);
        xfs_agino_t             pagino = XFS_INO_TO_AGINO(mp, parent);
-       struct xfs_perag        *pag;
+       struct xfs_perag        *pag = agbp->b_pag;
        struct xfs_btree_cur    *cur, *tcur;
        struct xfs_inobt_rec_incore rec, trec;
        xfs_ino_t               ino;
@@ -1143,8 +1142,6 @@ xfs_dialloc_ag_inobt(
        int                     i, j;
        int                     searchdistance = 10;
 
-       pag = xfs_perag_get(mp, agno);
-
        ASSERT(pag->pagi_init);
        ASSERT(pag->pagi_inodeok);
        ASSERT(pag->pagi_freecount > 0);
@@ -1384,14 +1381,12 @@ alloc_inode:
 
        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
        xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
-       xfs_perag_put(pag);
        *inop = ino;
        return 0;
 error1:
        xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
 error0:
        xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-       xfs_perag_put(pag);
        return error;
 }
 
@@ -1587,7 +1582,6 @@ xfs_dialloc_ag(
        xfs_agnumber_t                  agno = be32_to_cpu(agi->agi_seqno);
        xfs_agnumber_t                  pagno = XFS_INO_TO_AGNO(mp, parent);
        xfs_agino_t                     pagino = XFS_INO_TO_AGINO(mp, parent);
-       struct xfs_perag                *pag;
        struct xfs_btree_cur            *cur;   /* finobt cursor */
        struct xfs_btree_cur            *icur;  /* inobt cursor */
        struct xfs_inobt_rec_incore     rec;
@@ -1599,8 +1593,6 @@ xfs_dialloc_ag(
        if (!xfs_sb_version_hasfinobt(&mp->m_sb))
                return xfs_dialloc_ag_inobt(tp, agbp, parent, inop);
 
-       pag = xfs_perag_get(mp, agno);
-
        /*
         * If pagino is 0 (this is the root inode allocation) use newino.
         * This must work because we've just allocated some.
@@ -1667,7 +1659,7 @@ xfs_dialloc_ag(
         */
        be32_add_cpu(&agi->agi_freecount, -1);
        xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
-       pag->pagi_freecount--;
+       agbp->b_pag->pagi_freecount--;
 
        xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
 
@@ -1680,7 +1672,6 @@ xfs_dialloc_ag(
 
        xfs_btree_del_cursor(icur, XFS_BTREE_NOERROR);
        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
-       xfs_perag_put(pag);
        *inop = ino;
        return 0;
 
@@ -1688,7 +1679,6 @@ error_icur:
        xfs_btree_del_cursor(icur, XFS_BTREE_ERROR);
 error_cur:
        xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-       xfs_perag_put(pag);
        return error;
 }
 
@@ -1945,7 +1935,6 @@ xfs_difree_inobt(
 {
        struct xfs_agi                  *agi = agbp->b_addr;
        xfs_agnumber_t                  agno = be32_to_cpu(agi->agi_seqno);
-       struct xfs_perag                *pag;
        struct xfs_btree_cur            *cur;
        struct xfs_inobt_rec_incore     rec;
        int                             ilen;
@@ -2007,6 +1996,8 @@ xfs_difree_inobt(
        if (!(mp->m_flags & XFS_MOUNT_IKEEP) &&
            rec.ir_free == XFS_INOBT_ALL_FREE &&
            mp->m_sb.sb_inopblock <= XFS_INODES_PER_CHUNK) {
+               struct xfs_perag        *pag = agbp->b_pag;
+
                xic->deleted = true;
                xic->first_ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino);
                xic->alloc = xfs_inobt_irec_to_allocmask(&rec);
@@ -2020,10 +2011,8 @@ xfs_difree_inobt(
                be32_add_cpu(&agi->agi_count, -ilen);
                be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
                xfs_ialloc_log_agi(tp, agbp, XFS_AGI_COUNT | XFS_AGI_FREECOUNT);
-               pag = xfs_perag_get(mp, agno);
                pag->pagi_freecount -= ilen - 1;
                pag->pagi_count -= ilen;
-               xfs_perag_put(pag);
                xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
                xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
 
@@ -2049,9 +2038,7 @@ xfs_difree_inobt(
                 */
                be32_add_cpu(&agi->agi_freecount, 1);
                xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
-               pag = xfs_perag_get(mp, agno);
-               pag->pagi_freecount++;
-               xfs_perag_put(pag);
+               agbp->b_pag->pagi_freecount++;
                xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, 1);
        }
 
@@ -2661,7 +2648,7 @@ xfs_ialloc_read_agi(
                return error;
 
        agi = (*bpp)->b_addr;
-       pag = xfs_perag_get(mp, agno);
+       pag = (*bpp)->b_pag;
        if (!pag->pagi_init) {
                pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
                pag->pagi_count = be32_to_cpu(agi->agi_count);
@@ -2674,7 +2661,6 @@ xfs_ialloc_read_agi(
         */
        ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
                XFS_FORCED_SHUTDOWN(mp));
-       xfs_perag_put(pag);
        return 0;
 }
 

diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index 7fd6044..c5296c1 100644 (file)
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -37,15 +37,13 @@ xfs_refcountbt_set_root(
 {
        struct xfs_buf          *agbp = cur->bc_ag.agbp;
        struct xfs_agf          *agf = agbp->b_addr;
-       xfs_agnumber_t          seqno = be32_to_cpu(agf->agf_seqno);
-       struct xfs_perag        *pag = xfs_perag_get(cur->bc_mp, seqno);
+       struct xfs_perag        *pag = agbp->b_pag;
 
        ASSERT(ptr->s != 0);
 
        agf->agf_refcount_root = ptr->s;
        be32_add_cpu(&agf->agf_refcount_level, inc);
        pag->pagf_refcount_level += inc;
-       xfs_perag_put(pag);
 
        xfs_alloc_log_agf(cur->bc_tp, agbp,
                        XFS_AGF_REFCOUNT_ROOT | XFS_AGF_REFCOUNT_LEVEL);

diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index b7c0531..94948a5 100644 (file)
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -63,16 +63,14 @@ xfs_rmapbt_set_root(
 {
        struct xfs_buf          *agbp = cur->bc_ag.agbp;
        struct xfs_agf          *agf = agbp->b_addr;
-       xfs_agnumber_t          seqno = be32_to_cpu(agf->agf_seqno);
        int                     btnum = cur->bc_btnum;
-       struct xfs_perag        *pag = xfs_perag_get(cur->bc_mp, seqno);
+       struct xfs_perag        *pag = agbp->b_pag;
 
        ASSERT(ptr->s != 0);
 
        agf->agf_roots[btnum] = ptr->s;
        be32_add_cpu(&agf->agf_levels[btnum], inc);
        pag->pagf_levels[btnum] += inc;
-       xfs_perag_put(pag);
 
        xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
 }
@@ -123,6 +121,7 @@ xfs_rmapbt_free_block(
 {
        struct xfs_buf          *agbp = cur->bc_ag.agbp;
        struct xfs_agf          *agf = agbp->b_addr;
+       struct xfs_perag        *pag;
        xfs_agblock_t           bno;
        int                     error;
 
@@ -139,8 +138,8 @@ xfs_rmapbt_free_block(
                              XFS_EXTENT_BUSY_SKIP_DISCARD);
        xfs_trans_agbtree_delta(cur->bc_tp, -1);
 
-       xfs_ag_resv_rmapbt_free(cur->bc_mp, cur->bc_ag.agno);
-
+       pag = cur->bc_ag.agbp->b_pag;
+       xfs_ag_resv_free_extent(pag, XFS_AG_RESV_RMAPBT, NULL, 1);
        return 0;
 }
 

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 5c07bf4..407d629 100644 (file)
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2265,7 +2265,6 @@ xfs_iunlink(
        }
 
        if (next_agino != NULLAGINO) {
-               struct xfs_perag        *pag;
                xfs_agino_t             old_agino;
 
                /*
@@ -2282,9 +2281,7 @@ xfs_iunlink(
                 * agino has been unlinked, add a backref from the next inode
                 * back to agino.
                 */
-               pag = xfs_perag_get(mp, agno);
-               error = xfs_iunlink_add_backref(pag, agino, next_agino);
-               xfs_perag_put(pag);
+               error = xfs_iunlink_add_backref(agibp->b_pag, agino, next_agino);
                if (error)
                        return error;
        }
@@ -2420,7 +2417,6 @@ xfs_iunlink_remove(
        struct xfs_buf          *agibp;
        struct xfs_buf          *last_ibp;
        struct xfs_dinode       *last_dip = NULL;
-       struct xfs_perag        *pag = NULL;
        xfs_agnumber_t          agno = XFS_INO_TO_AGNO(mp, ip->i_ino);
        xfs_agino_t             agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
        xfs_agino_t             next_agino;
@@ -2464,32 +2460,22 @@ xfs_iunlink_remove(
         * this inode's backref to point from the next inode.
         */
        if (next_agino != NULLAGINO) {
-               pag = xfs_perag_get(mp, agno);
-               error = xfs_iunlink_change_backref(pag, next_agino,
+               error = xfs_iunlink_change_backref(agibp->b_pag, next_agino,
                                NULLAGINO);
                if (error)
-                       goto out;
+                       return error;
        }
 
-       if (head_agino == agino) {
-               /* Point the head of the list to the next unlinked inode. */
-               error = xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index,
-                               next_agino);
-               if (error)
-                       goto out;
-       } else {
+       if (head_agino != agino) {
                struct xfs_imap imap;
                xfs_agino_t     prev_agino;
 
-               if (!pag)
-                       pag = xfs_perag_get(mp, agno);
-
                /* We need to search the list for the inode being freed. */
                error = xfs_iunlink_map_prev(tp, agno, head_agino, agino,
                                &prev_agino, &imap, &last_dip, &last_ibp,
-                               pag);
+                               agibp->b_pag);
                if (error)
-                       goto out;
+                       return error;
 
                /* Point the previous inode on the list to the next inode. */
                xfs_iunlink_update_dinode(tp, agno, prev_agino, last_ibp,
@@ -2503,15 +2489,13 @@ xfs_iunlink_remove(
                 * change_backref takes care of deleting the backref if
                 * next_agino is NULLAGINO.
                 */
-               error = xfs_iunlink_change_backref(pag, agino, next_agino);
-               if (error)
-                       goto out;
+               return xfs_iunlink_change_backref(agibp->b_pag, agino,
+                               next_agino);
        }
 
-out:
-       if (pag)
-               xfs_perag_put(pag);
-       return error;
+       /* Point the head of the list to the next unlinked inode. */
+       return xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index,
+                       next_agino);
 }
 
 /*