[PATCH] JFS: reduce number of synchronous transactions

Use an inline pxd list rather than an xad list in the xadlock.
When the number of extents being modified can fit with the xadlock,
a transaction can be committed asynchronously.  Using a list of
pxd's instead of xad's allows us to fit 4 extents, rather than 2.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 40 insertions, 23 deletions

diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c
index f40301d93f74..98e16d93e146 100644
--- a/fs/jfs/jfs_txnmgr.c
+++ b/fs/jfs/jfs_txnmgr.c
@@ -1712,7 +1712,7 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
         struct maplock *maplock;
         struct xdlistlock *xadlock;
         struct pxd_lock *pxdlock;
-        pxd_t *pxd;
+        pxd_t *page_pxd;
         int next, lwm, hwm;
 
         ip = tlck->ip;
@@ -1722,7 +1722,7 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
         lrd->log.redopage.type = cpu_to_le16(LOG_XTREE);
         lrd->log.redopage.l2linesize = cpu_to_le16(L2XTSLOTSIZE);
 
-        pxd = &lrd->log.redopage.pxd;
+        page_pxd = &lrd->log.redopage.pxd;
 
         if (tlck->type & tlckBTROOT) {
                 lrd->log.redopage.type |= cpu_to_le16(LOG_BTROOT);
@@ -1752,9 +1752,9 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
                  * applying the after-image to the meta-data page.
                  */
                 lrd->type = cpu_to_le16(LOG_REDOPAGE);
-//              *pxd = mp->cm_pxd;
-                PXDaddress(pxd, mp->index);
-                PXDlength(pxd,
+//              *page_pxd = mp->cm_pxd;
+                PXDaddress(page_pxd, mp->index);
+                PXDlength(page_pxd,
                           mp->logical_size >> tblk->sb->s_blocksize_bits);
                 lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));
 
@@ -1776,25 +1776,31 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
                 tlck->flag |= tlckUPDATEMAP;
                 xadlock->flag = mlckALLOCXADLIST;
                 xadlock->count = next - lwm;
-                if ((xadlock->count <= 2) && (tblk->xflag & COMMIT_LAZY)) {
+                if ((xadlock->count <= 4) && (tblk->xflag & COMMIT_LAZY)) {
                         int i;
+                        pxd_t *pxd;
                         /*
                          * Lazy commit may allow xtree to be modified before
                          * txUpdateMap runs.  Copy xad into linelock to
                          * preserve correct data.
+                         *
+                         * We can fit twice as may pxd's as xads in the lock
                          */
-                        xadlock->xdlist = &xtlck->pxdlock;
-                        memcpy(xadlock->xdlist, &p->xad[lwm],
-                               sizeof(xad_t) * xadlock->count);
-
-                        for (i = 0; i < xadlock->count; i++)
+                        xadlock->flag = mlckALLOCPXDLIST;
+                        pxd = xadlock->xdlist = &xtlck->pxdlock;
+                        for (i = 0; i < xadlock->count; i++) {
+                                PXDaddress(pxd, addressXAD(&p->xad[lwm + i]));
+                                PXDlength(pxd, lengthXAD(&p->xad[lwm + i]));
                                 p->xad[lwm + i].flag &=
                                     ~(XAD_NEW | XAD_EXTENDED);
+                                pxd++;
+                        }
                 } else {
                         /*
                          * xdlist will point to into inode's xtree, ensure
                          * that transaction is not committed lazily.
                          */
+                        xadlock->flag = mlckALLOCXADLIST;
                         xadlock->xdlist = &p->xad[lwm];
                         tblk->xflag &= ~COMMIT_LAZY;
                 }
@@ -1836,8 +1842,8 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
                 if (tblk->xflag & COMMIT_TRUNCATE) {
                         /* write NOREDOPAGE for the page */
                         lrd->type = cpu_to_le16(LOG_NOREDOPAGE);
-                        PXDaddress(pxd, mp->index);
-                        PXDlength(pxd,
+                        PXDaddress(page_pxd, mp->index);
+                        PXDlength(page_pxd,
                                   mp->logical_size >> tblk->sb->
                                   s_blocksize_bits);
                         lrd->backchain =
@@ -1872,22 +1878,32 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
                  * deleted page itself;
                  */
                 tlck->flag |= tlckUPDATEMAP;
-                xadlock->flag = mlckFREEXADLIST;
                 xadlock->count = hwm - XTENTRYSTART + 1;
-                if ((xadlock->count <= 2) && (tblk->xflag & COMMIT_LAZY)) {
+                if ((xadlock->count <= 4) && (tblk->xflag & COMMIT_LAZY)) {
+                        int i;
+                        pxd_t *pxd;
                         /*
                          * Lazy commit may allow xtree to be modified before
                          * txUpdateMap runs.  Copy xad into linelock to
                          * preserve correct data.
+                         *
+                         * We can fit twice as may pxd's as xads in the lock
                          */
-                        xadlock->xdlist = &xtlck->pxdlock;
-                        memcpy(xadlock->xdlist, &p->xad[XTENTRYSTART],
-                               sizeof(xad_t) * xadlock->count);
+                        xadlock->flag = mlckFREEPXDLIST;
+                        pxd = xadlock->xdlist = &xtlck->pxdlock;
+                        for (i = 0; i < xadlock->count; i++) {
+                                PXDaddress(pxd,
+                                        addressXAD(&p->xad[XTENTRYSTART + i]));
+                                PXDlength(pxd,
+                                        lengthXAD(&p->xad[XTENTRYSTART + i]));
+                                pxd++;
+                        }
                 } else {
                         /*
                          * xdlist will point to into inode's xtree, ensure
                          * that transaction is not committed lazily.
                          */
+                        xadlock->flag = mlckFREEXADLIST;
                         xadlock->xdlist = &p->xad[XTENTRYSTART];
                         tblk->xflag &= ~COMMIT_LAZY;
                 }
@@ -1918,7 +1934,7 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
          * header ?
          */
         if (tlck->type & tlckTRUNCATE) {
-                pxd_t tpxd;     /* truncated extent of xad */
+                pxd_t pxd;      /* truncated extent of xad */
                 int twm;
 
                 /*
@@ -1947,8 +1963,9 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
                  * applying the after-image to the meta-data page.
                  */
                 lrd->type = cpu_to_le16(LOG_REDOPAGE);
-                PXDaddress(pxd, mp->index);
-                PXDlength(pxd, mp->logical_size >> tblk->sb->s_blocksize_bits);
+                PXDaddress(page_pxd, mp->index);
+                PXDlength(page_pxd,
+                          mp->logical_size >> tblk->sb->s_blocksize_bits);
                 lrd->backchain = cpu_to_le32(lmLog(log, tblk, lrd, tlck));
 
                 /*
@@ -1966,7 +1983,7 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
                         lrd->log.updatemap.type = cpu_to_le16(LOG_FREEPXD);
                         lrd->log.updatemap.nxd = cpu_to_le16(1);
                         lrd->log.updatemap.pxd = pxdlock->pxd;
-                        tpxd = pxdlock->pxd;    /* save to format maplock */
+                        pxd = pxdlock->pxd;     /* save to format maplock */
                         lrd->backchain =
                             cpu_to_le32(lmLog(log, tblk, lrd, NULL));
                 }
@@ -2035,7 +2052,7 @@ static void xtLog(struct jfs_log * log, struct tblock * tblk, struct lrd * lrd,
                         pxdlock = (struct pxd_lock *) xadlock;
                         pxdlock->flag = mlckFREEPXD;
                         pxdlock->count = 1;
-                        pxdlock->pxd = tpxd;
+                        pxdlock->pxd = pxd;
 
                         jfs_info("xtLog: truncate ip:0x%p mp:0x%p count:%d "
                                  "hwm:%d", ip, mp, pxdlock->count, hwm);