1 files changed, 136 insertions, 108 deletions

diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index ed575fb4b495..23d6ceb5e97b 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -146,102 +146,6 @@ xlog_cil_init_post_recovery(
 }
 
 /*
- * Insert the log item into the CIL and calculate the difference in space
- * consumed by the item. Add the space to the checkpoint ticket and calculate
- * if the change requires additional log metadata. If it does, take that space
- * as well. Remove the amount of space we addded to the checkpoint ticket from
- * the current transaction ticket so that the accounting works out correctly.
- *
- * If this is the first time the item is being placed into the CIL in this
- * context, pin it so it can't be written to disk until the CIL is flushed to
- * the iclog and the iclog written to disk.
- */
-static void
-xlog_cil_insert(
-	struct log		*log,
-	struct xlog_ticket	*ticket,
-	struct xfs_log_item	*item,
-	struct xfs_log_vec	*lv)
-{
-	struct xfs_cil		*cil = log->l_cilp;
-	struct xfs_log_vec	*old = lv->lv_item->li_lv;
-	struct xfs_cil_ctx	*ctx = cil->xc_ctx;
-	int			len;
-	int			diff_iovecs;
-	int			iclog_space;
-
-	if (old) {
-		/* existing lv on log item, space used is a delta */
-		ASSERT(!list_empty(&item->li_cil));
-		ASSERT(old->lv_buf && old->lv_buf_len && old->lv_niovecs);
-
-		len = lv->lv_buf_len - old->lv_buf_len;
-		diff_iovecs = lv->lv_niovecs - old->lv_niovecs;
-		kmem_free(old->lv_buf);
-		kmem_free(old);
-	} else {
-		/* new lv, must pin the log item */
-		ASSERT(!lv->lv_item->li_lv);
-		ASSERT(list_empty(&item->li_cil));
-
-		len = lv->lv_buf_len;
-		diff_iovecs = lv->lv_niovecs;
-		IOP_PIN(lv->lv_item);
-
-	}
-	len += diff_iovecs * sizeof(xlog_op_header_t);
-
-	/* attach new log vector to log item */
-	lv->lv_item->li_lv = lv;
-
-	spin_lock(&cil->xc_cil_lock);
-	list_move_tail(&item->li_cil, &cil->xc_cil);
-	ctx->nvecs += diff_iovecs;
-
-	/*
-	 * If this is the first time the item is being committed to the CIL,
-	 * store the sequence number on the log item so we can tell
-	 * in future commits whether this is the first checkpoint the item is
-	 * being committed into.
-	 */
-	if (!item->li_seq)
-		item->li_seq = ctx->sequence;
-
-	/*
-	 * Now transfer enough transaction reservation to the context ticket
-	 * for the checkpoint. The context ticket is special - the unit
-	 * reservation has to grow as well as the current reservation as we
-	 * steal from tickets so we can correctly determine the space used
-	 * during the transaction commit.
-	 */
-	if (ctx->ticket->t_curr_res == 0) {
-		/* first commit in checkpoint, steal the header reservation */
-		ASSERT(ticket->t_curr_res >= ctx->ticket->t_unit_res + len);
-		ctx->ticket->t_curr_res = ctx->ticket->t_unit_res;
-		ticket->t_curr_res -= ctx->ticket->t_unit_res;
-	}
-
-	/* do we need space for more log record headers? */
-	iclog_space = log->l_iclog_size - log->l_iclog_hsize;
-	if (len > 0 && (ctx->space_used / iclog_space !=
-				(ctx->space_used + len) / iclog_space)) {
-		int hdrs;
-
-		hdrs = (len + iclog_space - 1) / iclog_space;
-		/* need to take into account split region headers, too */
-		hdrs *= log->l_iclog_hsize + sizeof(struct xlog_op_header);
-		ctx->ticket->t_unit_res += hdrs;
-		ctx->ticket->t_curr_res += hdrs;
-		ticket->t_curr_res -= hdrs;
-		ASSERT(ticket->t_curr_res >= len);
-	}
-	ticket->t_curr_res -= len;
-	ctx->space_used += len;
-
-	spin_unlock(&cil->xc_cil_lock);
-}
-
-/*
  * Format log item into a flat buffers
  *
  * For delayed logging, we need to hold a formatted buffer containing all the
@@ -286,7 +190,7 @@ xlog_cil_format_items(
 			len += lv->lv_iovecp[index].i_len;
 
 		lv->lv_buf_len = len;
-		lv->lv_buf = kmem_zalloc(lv->lv_buf_len, KM_SLEEP|KM_NOFS);
+		lv->lv_buf = kmem_alloc(lv->lv_buf_len, KM_SLEEP|KM_NOFS);
 		ptr = lv->lv_buf;
 
 		for (index = 0; index < lv->lv_niovecs; index++) {
@@ -300,21 +204,136 @@ xlog_cil_format_items(
 	}
 }
 
+/*
+ * Prepare the log item for insertion into the CIL. Calculate the difference in
+ * log space and vectors it will consume, and if it is a new item pin it as
+ * well.
+ */
+STATIC void
+xfs_cil_prepare_item(
+	struct log		*log,
+	struct xfs_log_vec	*lv,
+	int			*len,
+	int			*diff_iovecs)
+{
+	struct xfs_log_vec	*old = lv->lv_item->li_lv;
+
+	if (old) {
+		/* existing lv on log item, space used is a delta */
+		ASSERT(!list_empty(&lv->lv_item->li_cil));
+		ASSERT(old->lv_buf && old->lv_buf_len && old->lv_niovecs);
+
+		*len += lv->lv_buf_len - old->lv_buf_len;
+		*diff_iovecs += lv->lv_niovecs - old->lv_niovecs;
+		kmem_free(old->lv_buf);
+		kmem_free(old);
+	} else {
+		/* new lv, must pin the log item */
+		ASSERT(!lv->lv_item->li_lv);
+		ASSERT(list_empty(&lv->lv_item->li_cil));
+
+		*len += lv->lv_buf_len;
+		*diff_iovecs += lv->lv_niovecs;
+		IOP_PIN(lv->lv_item);
+
+	}
+
+	/* attach new log vector to log item */
+	lv->lv_item->li_lv = lv;
+
+	/*
+	 * If this is the first time the item is being committed to the
+	 * CIL, store the sequence number on the log item so we can
+	 * tell in future commits whether this is the first checkpoint
+	 * the item is being committed into.
+	 */
+	if (!lv->lv_item->li_seq)
+		lv->lv_item->li_seq = log->l_cilp->xc_ctx->sequence;
+}
+
+/*
+ * Insert the log items into the CIL and calculate the difference in space
+ * consumed by the item. Add the space to the checkpoint ticket and calculate
+ * if the change requires additional log metadata. If it does, take that space
+ * as well. Remove the amount of space we addded to the checkpoint ticket from
+ * the current transaction ticket so that the accounting works out correctly.
+ */
 static void
 xlog_cil_insert_items(
 	struct log		*log,
 	struct xfs_log_vec	*log_vector,
-	struct xlog_ticket	*ticket,
-	xfs_lsn_t		*start_lsn)
+	struct xlog_ticket	*ticket)
 {
-	struct xfs_log_vec *lv;
-
-	if (start_lsn)
-		*start_lsn = log->l_cilp->xc_ctx->sequence;
+	struct xfs_cil		*cil = log->l_cilp;
+	struct xfs_cil_ctx	*ctx = cil->xc_ctx;
+	struct xfs_log_vec	*lv;
+	int			len = 0;
+	int			diff_iovecs = 0;
+	int			iclog_space;
 
 	ASSERT(log_vector);
+
+	/*
+	 * Do all the accounting aggregation and switching of log vectors
+	 * around in a separate loop to the insertion of items into the CIL.
+	 * Then we can do a separate loop to update the CIL within a single
+	 * lock/unlock pair. This reduces the number of round trips on the CIL
+	 * lock from O(nr_logvectors) to O(1) and greatly reduces the overall
+	 * hold time for the transaction commit.
+	 *
+	 * If this is the first time the item is being placed into the CIL in
+	 * this context, pin it so it can't be written to disk until the CIL is
+	 * flushed to the iclog and the iclog written to disk.
+	 *
+	 * We can do this safely because the context can't checkpoint until we
+	 * are done so it doesn't matter exactly how we update the CIL.
+	 */
 	for (lv = log_vector; lv; lv = lv->lv_next)
-		xlog_cil_insert(log, ticket, lv->lv_item, lv);
+		xfs_cil_prepare_item(log, lv, &len, &diff_iovecs);
+
+	/* account for space used by new iovec headers  */
+	len += diff_iovecs * sizeof(xlog_op_header_t);
+
+	spin_lock(&cil->xc_cil_lock);
+
+	/* move the items to the tail of the CIL */
+	for (lv = log_vector; lv; lv = lv->lv_next)
+		list_move_tail(&lv->lv_item->li_cil, &cil->xc_cil);
+
+	ctx->nvecs += diff_iovecs;
+
+	/*
+	 * Now transfer enough transaction reservation to the context ticket
+	 * for the checkpoint. The context ticket is special - the unit
+	 * reservation has to grow as well as the current reservation as we
+	 * steal from tickets so we can correctly determine the space used
+	 * during the transaction commit.
+	 */
+	if (ctx->ticket->t_curr_res == 0) {
+		/* first commit in checkpoint, steal the header reservation */
+		ASSERT(ticket->t_curr_res >= ctx->ticket->t_unit_res + len);
+		ctx->ticket->t_curr_res = ctx->ticket->t_unit_res;
+		ticket->t_curr_res -= ctx->ticket->t_unit_res;
+	}
+
+	/* do we need space for more log record headers? */
+	iclog_space = log->l_iclog_size - log->l_iclog_hsize;
+	if (len > 0 && (ctx->space_used / iclog_space !=
+				(ctx->space_used + len) / iclog_space)) {
+		int hdrs;
+
+		hdrs = (len + iclog_space - 1) / iclog_space;
+		/* need to take into account split region headers, too */
+		hdrs *= log->l_iclog_hsize + sizeof(struct xlog_op_header);
+		ctx->ticket->t_unit_res += hdrs;
+		ctx->ticket->t_curr_res += hdrs;
+		ticket->t_curr_res -= hdrs;
+		ASSERT(ticket->t_curr_res >= len);
+	}
+	ticket->t_curr_res -= len;
+	ctx->space_used += len;
+
+	spin_unlock(&cil->xc_cil_lock);
 }
 
 static void
@@ -405,9 +424,15 @@ xlog_cil_push(
 	new_ctx = kmem_zalloc(sizeof(*new_ctx), KM_SLEEP|KM_NOFS);
 	new_ctx->ticket = xlog_cil_ticket_alloc(log);
 
-	/* lock out transaction commit, but don't block on background push */
+	/*
+	 * Lock out transaction commit, but don't block for background pushes
+	 * unless we are well over the CIL space limit. See the definition of
+	 * XLOG_CIL_HARD_SPACE_LIMIT() for the full explanation of the logic
+	 * used here.
+	 */
 	if (!down_write_trylock(&cil->xc_ctx_lock)) {
-		if (!push_seq)
+		if (!push_seq &&
+		    cil->xc_ctx->space_used < XLOG_CIL_HARD_SPACE_LIMIT(log))
 			goto out_free_ticket;
 		down_write(&cil->xc_ctx_lock);
 	}
@@ -422,7 +447,7 @@ xlog_cil_push(
 		goto out_skip;
 
 	/* check for a previously pushed seqeunce */
-	if (push_seq < cil->xc_ctx->sequence)
+	if (push_seq && push_seq < cil->xc_ctx->sequence)
 		goto out_skip;
 
 	/*
@@ -632,7 +657,10 @@ xfs_log_commit_cil(
 
 	/* lock out background commit */
 	down_read(&log->l_cilp->xc_ctx_lock);
-	xlog_cil_insert_items(log, log_vector, tp->t_ticket, commit_lsn);
+	if (commit_lsn)
+		*commit_lsn = log->l_cilp->xc_ctx->sequence;
+
+	xlog_cil_insert_items(log, log_vector, tp->t_ticket);
 
 	/* check we didn't blow the reservation */
 	if (tp->t_ticket->t_curr_res < 0)