Factor out mdb_find_oldest,mdb_dlist_free,dirty_list.

Do not rescan reader table (mdb_find_oldest) after "goto again".
Skip clearing dirty_list[nonzero].mid in mdb_dlist_free(); it
was not done in mdb_reset0() anyway.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 4c85d67ea6a03f437617dd50228e4457068ce3d1..5558875872163b2ced0fcf796ed486235316eaca 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -1289,6 +1289,44 @@ mdb_page_free(MDB_env *env, MDB_page *mp)
        env->me_dpages = mp;
 }
 
+/* Return all dirty pages to dpage list */
+static void
+mdb_dlist_free(MDB_txn *txn)
+{
+       MDB_env *env = txn->mt_env;
+       MDB_ID2L dl = txn->mt_u.dirty_list;
+       unsigned i, n = dl[0].mid;
+
+       for (i = 1; i <= n; i++) {
+               MDB_page *dp = dl[i].mptr;
+               if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
+                       mdb_page_free(env, dp);
+               } else {
+                       /* large pages just get freed directly */
+                       VGMEMP_FREE(env, dp);
+                       free(dp);
+               }
+       }
+       dl[0].mid = 0;
+}
+
+/** Find oldest txnid still referenced. Expects txn->mt_txnid > 0. */
+static txnid_t
+mdb_find_oldest(MDB_txn *txn)
+{
+       int i;
+       txnid_t mr, oldest = txn->mt_txnid - 1;
+       MDB_reader *r = txn->mt_env->me_txns->mti_readers;
+       for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {
+               if (r[i].mr_pid) {
+                       mr = r[i].mr_txnid;
+                       if (oldest > mr)
+                               oldest = mr;
+               }
+       }
+       return oldest;
+}
+
 /** Allocate pages for writing.
  * If there are free pages available from older transactions, they
  * will be re-used first. Otherwise a new page will be allocated.
@@ -1323,7 +1361,6 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
                if (!txn->mt_env->me_pghead &&
                        txn->mt_dbs[FREE_DBI].md_root != P_INVALID) {
                        /* See if there's anything in the free DB */
-                       MDB_reader *r;
                        MDB_cursor m2;
                        MDB_node *leaf;
                        MDB_val data;
@@ -1348,19 +1385,8 @@ again:
                                last = *(txnid_t *)key.mv_data;
                        }
 
-                       {
-                               unsigned int i, nr;
-                               txnid_t mr;
-                               oldest = txn->mt_txnid - 1;
-                               nr = txn->mt_env->me_txns->mti_numreaders;
-                               r = txn->mt_env->me_txns->mti_readers;
-                               for (i=0; i<nr; i++) {
-                                       if (!r[i].mr_pid) continue;
-                                       mr = r[i].mr_txnid;
-                                       if (mr < oldest)
-                                               oldest = mr;
-                               }
-                       }
+                       if (!oldest)
+                               oldest = mdb_find_oldest(txn);
 
                        if (oldest > last) {
                                /* It's usable, grab it.
@@ -1429,19 +1455,7 @@ none:
 
                                                /* We haven't hit the readers list yet? */
                                                if (!oldest) {
-                                                       MDB_reader *r;
-                                                       unsigned int nr;
-                                                       txnid_t mr;
-
-                                                       oldest = txn->mt_txnid - 1;
-                                                       nr = txn->mt_env->me_txns->mti_numreaders;
-                                                       r = txn->mt_env->me_txns->mti_readers;
-                                                       for (i=0; i<nr; i++) {
-                                                               if (!r[i].mr_pid) continue;
-                                                               mr = r[i].mr_txnid;
-                                                               if (mr < oldest)
-                                                                       oldest = mr;
-                                                       }
+                                                       oldest = mdb_find_oldest(txn);
                                                }
 
                                                /* There's nothing we can use on the freelist */
@@ -1635,22 +1649,20 @@ finish:
                        mc->mc_db->md_root = mp->mp_pgno;
        } else if (mc->mc_txn->mt_parent && !(mp->mp_flags & P_SUBP)) {
                MDB_page *np;
-               MDB_ID2 mid;
+               MDB_ID2 mid, *dl = mc->mc_txn->mt_u.dirty_list;
                /* If txn has a parent, make sure the page is in our
                 * dirty list.
                 */
-               if (mc->mc_txn->mt_u.dirty_list[0].mid) {
-                       unsigned x = mdb_mid2l_search(mc->mc_txn->mt_u.dirty_list, mp->mp_pgno);
-                       if (x <= mc->mc_txn->mt_u.dirty_list[0].mid &&
-                               mc->mc_txn->mt_u.dirty_list[x].mid == mp->mp_pgno) {
-                               if (mc->mc_txn->mt_u.dirty_list[x].mptr != mp) {
-                                       mp = mc->mc_txn->mt_u.dirty_list[x].mptr;
-                                       mc->mc_pg[mc->mc_top] = mp;
-                               }
+               if (dl[0].mid) {
+                       unsigned x = mdb_mid2l_search(dl, mp->mp_pgno);
+                       if (x <= dl[0].mid && dl[x].mid == mp->mp_pgno) {
+                               np = dl[x].mptr;
+                               if (mp != np)
+                                       mc->mc_pg[mc->mc_top] = np;
                                return 0;
                        }
                }
-               assert(mc->mc_txn->mt_u.dirty_list[0].mid < MDB_IDL_UM_MAX);
+               assert(dl[0].mid < MDB_IDL_UM_MAX);
                /* No - copy it */
                np = mdb_page_malloc(mc, 1);
                if (!np)
@@ -1658,7 +1670,7 @@ finish:
                memcpy(np, mp, mc->mc_txn->mt_env->me_psize);
                mid.mid = np->mp_pgno;
                mid.mptr = np;
-               mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &mid);
+               mdb_mid2l_insert(dl, &mid);
                mp = np;
                goto finish;
        }
@@ -2031,7 +2043,6 @@ static void
 mdb_txn_reset0(MDB_txn *txn)
 {
        MDB_env *env = txn->mt_env;
-       unsigned int i;
 
        /* Close any DBI handles opened in this txn */
        mdb_dbis_update(txn, 0);
@@ -2045,24 +2056,11 @@ mdb_txn_reset0(MDB_txn *txn)
                txn->mt_numdbs = 0;             /* close nothing if called again */
                txn->mt_dbxs = NULL;    /* mark txn as reset */
        } else {
-               MDB_page *dp;
-
                mdb_cursors_close(txn, 0);
 
                if (!(env->me_flags & MDB_WRITEMAP)) {
-                       /* return all dirty pages to dpage list */
-                       for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
-                               dp = txn->mt_u.dirty_list[i].mptr;
-                               if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
-                                       mdb_page_free(txn->mt_env, dp);
-                               } else {
-                                       /* large pages just get freed directly */
-                                       VGMEMP_FREE(txn->mt_env, dp);
-                                       free(dp);
-                               }
-                       }
+                       mdb_dlist_free(txn);
                }
-
                free(env->me_pgfree);
 
                if (txn->mt_parent) {
@@ -2415,7 +2413,6 @@ free2:
                        dp = txn->mt_u.dirty_list[i].mptr;
                        /* clear dirty flag */
                        dp->mp_flags &= ~P_DIRTY;
-                       txn->mt_u.dirty_list[i].mid = 0;
                }
                txn->mt_u.dirty_list[0].mid = 0;
                goto sync;
@@ -2513,19 +2510,7 @@ free2:
 #endif
        } while (!done);
 
-       /* Drop the dirty pages.
-        */
-       for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
-               dp = txn->mt_u.dirty_list[i].mptr;
-               if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
-                       mdb_page_free(txn->mt_env, dp);
-               } else {
-                       VGMEMP_FREE(txn->mt_env, dp);
-                       free(dp);
-               }
-               txn->mt_u.dirty_list[i].mid = 0;
-       }
-       txn->mt_u.dirty_list[0].mid = 0;
+       mdb_dlist_free(txn);
 
 sync:
        if ((n = mdb_env_sync(env, 0)) != 0 ||