xfs: pass lv chain length into xlog_write()

The caller of xlog_write() usually has a close accounting of the
aggregated vector length contained in the log vector chain passed to
xlog_write(). There is no need to iterate the chain to calculate he
length of the data in xlog_write_calculate_len() if the caller is
already iterating that chain to build it.

Passing in the vector length avoids doing an extra chain iteration,
which can be a significant amount of work given that large CIL
commits can have hundreds of thousands of vectors attached to the
chain.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 4e3fc28..e03a941 100644 (file)
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -958,7 +958,8 @@ xlog_write_unmount_record(
        /* account for space used by record data */
        ticket->t_curr_res -= sizeof(unmount_rec);
 
-       return xlog_write(log, NULL, &vec, ticket, XLOG_UNMOUNT_TRANS);
+       return xlog_write(log, NULL, &vec, ticket, XLOG_UNMOUNT_TRANS,
+                       reg.i_len);
 }
 
 /*
@@ -2209,32 +2210,6 @@ xlog_print_trans(
        }
 }
 
-/*
- * Calculate the potential space needed by the log vector. All regions contain
- * their own opheaders and they are accounted for in region space so we don't
- * need to add them to the vector length here.
- */
-static int
-xlog_write_calc_vec_length(
-       struct xlog_ticket      *ticket,
-       struct xfs_log_vec      *log_vector,
-       uint                    optype)
-{
-       struct xfs_log_vec      *lv;
-       int                     len = 0;
-       int                     i;
-
-       for (lv = log_vector; lv; lv = lv->lv_next) {
-               /* we don't write ordered log vectors */
-               if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED)
-                       continue;
-
-               for (i = 0; i < lv->lv_niovecs; i++)
-                       len += lv->lv_iovecp[i].i_len;
-       }
-       return len;
-}
-
 static xlog_op_header_t *
 xlog_write_setup_ophdr(
        struct xlog_op_header   *ophdr,
@@ -2388,13 +2363,14 @@ xlog_write(
        struct xfs_cil_ctx      *ctx,
        struct xfs_log_vec      *log_vector,
        struct xlog_ticket      *ticket,
-       uint                    optype)
+       uint                    optype,
+       uint32_t                len)
+
 {
        struct xlog_in_core     *iclog = NULL;
        struct xfs_log_vec      *lv = log_vector;
        struct xfs_log_iovec    *vecp = lv->lv_iovecp;
        int                     index = 0;
-       int                     len;
        int                     partial_copy = 0;
        int                     partial_copy_len = 0;
        int                     contwr = 0;
@@ -2409,7 +2385,6 @@ xlog_write(
                xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
        }
 
-       len = xlog_write_calc_vec_length(ticket, log_vector, optype);
        while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
                void            *ptr;
                int             log_offset;

diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index 5ccbb6b..dad2b52 100644 (file)
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -825,7 +825,8 @@ restart:
 static int
 xlog_cil_write_chain(
        struct xfs_cil_ctx      *ctx,
-       struct xfs_log_vec      *chain)
+       struct xfs_log_vec      *chain,
+       uint32_t                chain_len)
 {
        struct xlog             *log = ctx->cil->xc_log;
        int                     error;
@@ -833,7 +834,8 @@ xlog_cil_write_chain(
        error = xlog_cil_order_write(ctx->cil, ctx->sequence, _START_RECORD);
        if (error)
                return error;
-       return xlog_write(log, ctx, chain, ctx->ticket, XLOG_START_TRANS);
+       return xlog_write(log, ctx, chain, ctx->ticket, XLOG_START_TRANS,
+                       chain_len);
 }
 
 /*
@@ -872,7 +874,8 @@ xlog_cil_write_commit_record(
 
        /* account for space used by record data */
        ctx->ticket->t_curr_res -= reg.i_len;
-       error = xlog_write(log, ctx, &vec, ctx->ticket, XLOG_COMMIT_TRANS);
+       error = xlog_write(log, ctx, &vec, ctx->ticket, XLOG_COMMIT_TRANS,
+                       reg.i_len);
        if (error)
                xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
        return error;
@@ -935,11 +938,12 @@ xlog_cil_build_trans_hdr(
                                sizeof(struct xfs_trans_header);
        hdr->lhdr[1].i_type = XLOG_REG_TYPE_TRANSHDR;
 
-       tic->t_curr_res -= hdr->lhdr[0].i_len + hdr->lhdr[1].i_len;
-
        lvhdr->lv_niovecs = 2;
        lvhdr->lv_iovecp = &hdr->lhdr[0];
+       lvhdr->lv_bytes = hdr->lhdr[0].i_len + hdr->lhdr[1].i_len;
        lvhdr->lv_next = ctx->lv_chain;
+
+       tic->t_curr_res -= lvhdr->lv_bytes;
 }
 
 /*
@@ -966,7 +970,8 @@ xlog_cil_push_work(
        struct xlog             *log = cil->xc_log;
        struct xfs_log_vec      *lv;
        struct xfs_cil_ctx      *new_ctx;
-       int                     num_iovecs;
+       int                     num_iovecs = 0;
+       int                     num_bytes = 0;
        int                     error = 0;
        struct xlog_cil_trans_hdr thdr;
        struct xfs_log_vec      lvhdr = { NULL };
@@ -1047,7 +1052,6 @@ xlog_cil_push_work(
         * by the flush lock.
         */
        lv = NULL;
-       num_iovecs = 0;
        while (!list_empty(&cil->xc_cil)) {
                struct xfs_log_item     *item;
 
@@ -1061,6 +1065,10 @@ xlog_cil_push_work(
                lv = item->li_lv;
                item->li_lv = NULL;
                num_iovecs += lv->lv_niovecs;
+
+               /* we don't write ordered log vectors */
+               if (lv->lv_buf_len != XFS_LOG_VEC_ORDERED)
+                       num_bytes += lv->lv_bytes;
        }
 
        /*
@@ -1099,8 +1107,9 @@ xlog_cil_push_work(
         * transaction header here as it is not accounted for in xlog_write().
         */
        xlog_cil_build_trans_hdr(ctx, &thdr, &lvhdr, num_iovecs);
+       num_bytes += lvhdr.lv_bytes;
 
-       error = xlog_cil_write_chain(ctx, &lvhdr);
+       error = xlog_cil_write_chain(ctx, &lvhdr, num_bytes);
        if (error)
                goto out_abort_free_ticket;
 

diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index b588bb3..a070a2c 100644 (file)
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -503,7 +503,7 @@ void        xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
 void   xlog_print_trans(struct xfs_trans *);
 int    xlog_write(struct xlog *log, struct xfs_cil_ctx *ctx,
                struct xfs_log_vec *log_vector, struct xlog_ticket *tic,
-               uint optype);
+               uint optype, uint32_t len);
 void   xfs_log_ticket_ungrant(struct xlog *log, struct xlog_ticket *ticket);
 void   xfs_log_ticket_regrant(struct xlog *log, struct xlog_ticket *ticket);