From: Michael Schroeder <mls@suse.de>
Date: Tue, 17 Nov 2015 14:33:52 +0000 (+0100)
Subject: Overshoot size for large memory chunks in solv_extend
X-Git-Tag: 0.6.15~25
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a8220fe1d69f96825a912df96d1a2212f5c61b85;p=thirdparty%2Flibsolv.git

Overshoot size for large memory chunks in solv_extend

We now dynamically round up the size to some ppower of two. This
brings down the number of mremap calls fro 96163 to 675 when
converting Fedora22's Everything repo, which makes no real difference
on my system but seems to help a lot if this is done in a Xen
guest. See libsolv issue#111 on github.
---

diff --git a/src/libsolv.ver b/src/libsolv.ver
index 9e47117d..5d372aab 100644
--- a/src/libsolv.ver
+++ b/src/libsolv.ver
@@ -262,6 +262,7 @@ SOLV_1.0 {
 		solv_depmarker;
 		solv_dupappend;
 		solv_dupjoin;
+		solv_extend_realloc;
 		solv_free;
 		solv_hex2bin;
 		solv_latin1toutf8;
diff --git a/src/util.c b/src/util.c
index d8ae7cab..8be29351 100644
--- a/src/util.c
+++ b/src/util.c
@@ -76,6 +76,29 @@ solv_calloc(size_t num, size_t len)
   return r;
 }
 
+/* this was solv_realloc2(old, len, size), but we now overshoot
+ * for huge len sizes */
+void *
+solv_extend_realloc(void *old, size_t len, size_t size, size_t block)
+{
+  size_t xblock = (block + 1) << 5;
+  if (len >= xblock && xblock)
+    {
+      xblock <<= 1;
+      while (len >= xblock && xblock)
+	xblock <<= 1;
+      if (xblock)
+	{
+	  size_t nlen;
+          xblock = (xblock >> 5) - 1;
+	  nlen = (len + xblock) & ~xblock;
+	  if (nlen > len)
+	    len = nlen;
+	}
+    }
+  return solv_realloc2(old, len, size);
+}
+
 void *
 solv_free(void *mem)
 {
diff --git a/src/util.h b/src/util.h
index d8a136d6..60dd49cc 100644
--- a/src/util.h
+++ b/src/util.h
@@ -29,6 +29,7 @@ extern void *solv_malloc2(size_t, size_t);
 extern void *solv_calloc(size_t, size_t);
 extern void *solv_realloc(void *, size_t);
 extern void *solv_realloc2(void *, size_t, size_t);
+extern void *solv_extend_realloc(void *, size_t, size_t, size_t);
 extern void *solv_free(void *);
 extern char *solv_strdup(const char *);
 extern void solv_oom(size_t, size_t);
@@ -48,12 +49,12 @@ static inline void *solv_extend(void *buf, size_t len, size_t nmemb, size_t size
   if (nmemb == 1)
     {
       if ((len & block) == 0)
-	buf = solv_realloc2(buf, len + (1 + block), size);
+	buf = solv_extend_realloc(buf, len + (1 + block), size, block);
     }
   else
     {
       if (((len - 1) | block) != ((len + nmemb - 1) | block))
-	buf = solv_realloc2(buf, (len + (nmemb + block)) & ~block, size);
+	buf = solv_extend_realloc(buf, (len + (nmemb + block)) & ~block, size, block);
     }
   return buf;
 }
@@ -76,7 +77,7 @@ static inline void *solv_zextend(void *buf, size_t len, size_t nmemb, size_t siz
 static inline void *solv_extend_resize(void *buf, size_t len, size_t size, size_t block)
 {
   if (len)
-    buf = solv_realloc2(buf, (len + block) & ~block, size);
+    buf = solv_extend_realloc(buf, (len + block) & ~block, size, block);
   return buf;
 }
 
@@ -85,7 +86,7 @@ static inline void *solv_calloc_block(size_t len, size_t size, size_t block)
   void *buf;
   if (!len)
     return 0;
-  buf = solv_malloc2((len + block) & ~block, size);
+  buf = solv_extend_realloc((void *)0, (len + block) & ~block, size, block);
   memset(buf, 0, ((len + block) & ~block) * size);
   return buf;
 }