On Fri, Jun 05, 2020 at 04:52:00PM +0800, Gao Xiang wrote: > 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@xxxxxxxxxx> > Cc: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx> > Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxx> > --- > changes since v2: > kill unneeded ASSERTs, leaving which first brought > into a context pointed out by Dave (including callback > entrances). > > fs/xfs/libxfs/xfs_ag.c | 4 ++-- > fs/xfs/libxfs/xfs_ag_resv.h | 12 ---------- > fs/xfs/libxfs/xfs_alloc.c | 23 +++++++----------- > fs/xfs/libxfs/xfs_alloc_btree.c | 10 ++++---- > fs/xfs/libxfs/xfs_ialloc.c | 29 +++++++---------------- > fs/xfs/libxfs/xfs_refcount_btree.c | 5 ++-- > fs/xfs/libxfs/xfs_rmap_btree.c | 11 +++++---- > fs/xfs/xfs_inode.c | 38 +++++++++--------------------- > 8 files changed, 41 insertions(+), 91 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c > index 9d84007a5c65..8cf73fe4338e 100644 > --- 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 f3fd0ee9a7f7..8a8eb4bc48bb 100644 > --- 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 203e74fa64aa..6c40b0cb4fcc 100644 > --- 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 +2999,8 @@ xfs_alloc_read_agf( > ASSERT(!(*bpp)->b_error); > > agf = (*bpp)->b_addr; > - pag = xfs_perag_get(mp, agno); > + pag = (*bpp)->b_pag; > + ASSERT(pag->pag_agno == agno); I thought these assertions were all dropped in v3? Alternately-- if you want to sanity check that b_pag and the buffer belong to the same ag, why not do that in xfs_buf_find for all the buffers? > if (!pag->pagf_init) { > pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks); > pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks); > @@ -3034,7 +3028,6 @@ 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 60c453cb3ee3..c1d276f791ea 100644 > --- a/fs/xfs/libxfs/xfs_alloc_btree.c > +++ b/fs/xfs/libxfs/xfs_alloc_btree.c > @@ -38,16 +38,15 @@ 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); > + ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno)); I still see a few of these after-the-fact agno checks throughout the patch. --D > > 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 +114,6 @@ 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 +158,9 @@ xfs_allocbt_update_lastrec( > } > > agf->agf_longest = len; > - pag = xfs_perag_get(cur->bc_mp, seqno); > + pag = cur->bc_ag.agbp->b_pag; > + ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno)); > 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 7fcf62b324b0..14aa1faaa081 100644 > --- a/fs/xfs/libxfs/xfs_ialloc.c > +++ b/fs/xfs/libxfs/xfs_ialloc.c > @@ -888,10 +888,9 @@ xfs_ialloc_ag_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 @@ xfs_dialloc_ag_inobt( > > 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 @@ xfs_dialloc_ag( > 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 +2648,8 @@ xfs_ialloc_read_agi( > return error; > > agi = (*bpp)->b_addr; > - pag = xfs_perag_get(mp, agno); > + pag = (*bpp)->b_pag; > + ASSERT(pag->pag_agno == agno); > if (!pag->pagi_init) { > pag->pagi_freecount = be32_to_cpu(agi->agi_freecount); > pag->pagi_count = be32_to_cpu(agi->agi_count); > @@ -2674,7 +2662,6 @@ 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 7fd6044a4f78..f445a8e2d04e 100644 > --- a/fs/xfs/libxfs/xfs_refcount_btree.c > +++ b/fs/xfs/libxfs/xfs_refcount_btree.c > @@ -37,15 +37,14 @@ 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); > + ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno)); > > 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 b7c05314d07c..be660b2fd422 100644 > --- a/fs/xfs/libxfs/xfs_rmap_btree.c > +++ b/fs/xfs/libxfs/xfs_rmap_btree.c > @@ -63,16 +63,15 @@ 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); > + ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno)); > > 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 +122,7 @@ 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 +139,9 @@ 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; > + ASSERT(pag->pag_agno == cur->bc_ag.agno); > + 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 64f5f9a440ae..d0e7db7a2c32 100644 > --- a/fs/xfs/xfs_inode.c > +++ b/fs/xfs/xfs_inode.c > @@ -2248,7 +2248,6 @@ xfs_iunlink( > } > > if (next_agino != NULLAGINO) { > - struct xfs_perag *pag; > xfs_agino_t old_agino; > > /* > @@ -2265,9 +2264,7 @@ 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; > } > @@ -2403,7 +2400,6 @@ 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; > @@ -2447,32 +2443,22 @@ 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, > @@ -2486,15 +2472,13 @@ 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); > } > > /* > -- > 2.18.1 >