From 1bf2743e08ba66cc141e296812839947223e4370 Mon Sep 17 00:00:00 2001
From: Jason Evans <jasone@canonware.com>
Date: Sun, 23 Dec 2012 08:51:48 -0800
Subject: [PATCH] Add clipping support to lg_chunk option processing.

Modify processing of the lg_chunk option so that it clips an
out-of-range input to the edge of the valid range.  This makes it
possible to request the minimum possible chunk size without intimate
knowledge of allocator internals.

Submitted by Ian Lepore (see FreeBSD PR bin/174641).
---
 doc/jemalloc.xml.in |  7 +++++--
 src/jemalloc.c      | 42 +++++++++++++++++++++++-------------------
 2 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/doc/jemalloc.xml.in b/doc/jemalloc.xml.in
index 54b87474..09305801 100644
--- a/doc/jemalloc.xml.in
+++ b/doc/jemalloc.xml.in
@@ -790,8 +790,11 @@ for (i = 0; i < nbins; i++) {
           (<type>size_t</type>)
           <literal>r-</literal>
         </term>
-        <listitem><para>Virtual memory chunk size (log base 2).  The default
-        chunk size is 4 MiB (2^22).</para></listitem>
+        <listitem><para>Virtual memory chunk size (log base 2).  If a chunk
+        size outside the supported size range is specified, the size is
+        silently clipped to the minimum/maximum supported size.  The default
+        chunk size is 4 MiB (2^22).
+        </para></listitem>
       </varlistentry>
 
       <varlistentry id="opt.dss">
diff --git a/src/jemalloc.c b/src/jemalloc.c
index 8a667b62..cecd012c 100644
--- a/src/jemalloc.c
+++ b/src/jemalloc.c
@@ -469,7 +469,7 @@ malloc_conf_init(void)
 
 		while (*opts != '\0' && malloc_conf_next(&opts, &k, &klen, &v,
 		    &vlen) == false) {
-#define	CONF_HANDLE_BOOL_HIT(o, n, hit)					\
+#define	CONF_HANDLE_BOOL(o, n)						\
 			if (sizeof(n)-1 == klen && strncmp(n, k,	\
 			    klen) == 0) {				\
 				if (strncmp("true", v, vlen) == 0 &&	\
@@ -483,16 +483,9 @@ malloc_conf_init(void)
 					    "Invalid conf value",	\
 					    k, klen, v, vlen);		\
 				}					\
-				hit = true;				\
-			} else						\
-				hit = false;
-#define	CONF_HANDLE_BOOL(o, n) {					\
-			bool hit;					\
-			CONF_HANDLE_BOOL_HIT(o, n, hit);		\
-			if (hit)					\
 				continue;				\
-}
-#define	CONF_HANDLE_SIZE_T(o, n, min, max)				\
+			}
+#define	CONF_HANDLE_SIZE_T(o, n, min, max, clip)			\
 			if (sizeof(n)-1 == klen && strncmp(n, k,	\
 			    klen) == 0) {				\
 				uintmax_t um;				\
@@ -505,12 +498,22 @@ malloc_conf_init(void)
 					malloc_conf_error(		\
 					    "Invalid conf value",	\
 					    k, klen, v, vlen);		\
-				} else if (um < min || um > max) {	\
-					malloc_conf_error(		\
-					    "Out-of-range conf value",	\
-					    k, klen, v, vlen);		\
-				} else					\
-					o = um;				\
+				} else if (clip) {			\
+					if (um < min)			\
+						o = min;		\
+					else if (um > max)		\
+						o = max;		\
+					else				\
+						o = um;			\
+				} else {				\
+					if (um < min || um > max) {	\
+						malloc_conf_error(	\
+						    "Out-of-range "	\
+						    "conf value",	\
+						    k, klen, v, vlen);	\
+					} else				\
+						o = um;			\
+				}					\
 				continue;				\
 			}
 #define	CONF_HANDLE_SSIZE_T(o, n, min, max)				\
@@ -555,7 +558,8 @@ malloc_conf_init(void)
 			 * config_fill.
 			 */
 			CONF_HANDLE_SIZE_T(opt_lg_chunk, "lg_chunk", LG_PAGE +
-			    (config_fill ? 2 : 1), (sizeof(size_t) << 3) - 1)
+			    (config_fill ? 2 : 1), (sizeof(size_t) << 3) - 1,
+			    true)
 			if (strncmp("dss", k, klen) == 0) {
 				int i;
 				bool match = false;
@@ -581,14 +585,14 @@ malloc_conf_init(void)
 				continue;
 			}
 			CONF_HANDLE_SIZE_T(opt_narenas, "narenas", 1,
-			    SIZE_T_MAX)
+			    SIZE_T_MAX, false)
 			CONF_HANDLE_SSIZE_T(opt_lg_dirty_mult, "lg_dirty_mult",
 			    -1, (sizeof(size_t) << 3) - 1)
 			CONF_HANDLE_BOOL(opt_stats_print, "stats_print")
 			if (config_fill) {
 				CONF_HANDLE_BOOL(opt_junk, "junk")
 				CONF_HANDLE_SIZE_T(opt_quarantine, "quarantine",
-				    0, SIZE_T_MAX)
+				    0, SIZE_T_MAX, false)
 				CONF_HANDLE_BOOL(opt_redzone, "redzone")
 				CONF_HANDLE_BOOL(opt_zero, "zero")
 			}