From 3ba5bebec4f4ac8e8f239db1c7db666ea838e838 Mon Sep 17 00:00:00 2001
From: Leo Yuriev <leo@yuriev.ru>
Date: Sun, 23 Jul 2017 15:48:34 +0300
Subject: [PATCH] mdbx: refine mdbx_txl_alloc().

Change-Id: I624a92c8a845ab563f13619b3638227d012a780b
---
 src/mdbx.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/mdbx.c b/src/mdbx.c
index ac12cec6..134ee36a 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -176,10 +176,14 @@ static MDBX_IDL mdbx_midl_alloc(size_t size) {
   return ids;
 }
 
-static MDBX_TXL mdbx_txl_alloc(size_t size) {
-  MDBX_TXL ptr = malloc((size + 2) * sizeof(txnid_t));
+static MDBX_TXL mdbx_txl_alloc(void) {
+  const size_t malloc_overhead = sizeof(void *) * 2;
+  const size_t bytes = mdbx_roundup2(malloc_overhead + sizeof(txnid_t) * 61,
+                                     MDBX_CACHELINE_SIZE) -
+                       malloc_overhead;
+  MDBX_TXL ptr = malloc(bytes);
   if (likely(ptr)) {
-    *ptr++ = size;
+    *ptr++ = bytes / sizeof(txnid_t) - 2;
     *ptr = 0;
   }
   return ptr;
@@ -1774,7 +1778,7 @@ static int mdbx_page_alloc(MDBX_cursor *mc, unsigned num, MDBX_page **mp,
         goto fail;
 
       if ((flags & MDBX_LIFORECLAIM) && !txn->mt_lifo_reclaimed) {
-        txn->mt_lifo_reclaimed = mdbx_txl_alloc(env->me_maxfree_1pg);
+        txn->mt_lifo_reclaimed = mdbx_txl_alloc();
         if (unlikely(!txn->mt_lifo_reclaimed)) {
           rc = MDBX_ENOMEM;
           goto fail;
@@ -3045,7 +3049,7 @@ again:
         }
 
         if (unlikely(!txn->mt_lifo_reclaimed)) {
-          txn->mt_lifo_reclaimed = mdbx_txl_alloc(env->me_maxfree_1pg);
+          txn->mt_lifo_reclaimed = mdbx_txl_alloc();
           if (unlikely(!txn->mt_lifo_reclaimed)) {
             rc = MDBX_ENOMEM;
             goto bailout;