@@ -147,12 +147,35 @@ jobs:
           MAKE_TGT: 'test'
         run: script -e unit_tests.log -c 'sh -x scripts/build/do_build.sh DEFS_EXTRA_OPTS="-DUNIT_TESTS -fPIE -fPIC"'
 
+      # the same tests and the allocator suites with HG_MALLOC; the grep fails
+      # the step if HG_MALLOC was not actually the allocator under test (not
+      # anchored: other processes' log lines can share a line with the TAP one)
+      - name: Run tests with HG_MALLOC
+        env:
+          MAKE_TGT: 'test'
+          UT_ALLOC: 'HG_MALLOC'
+          UT_MEM: '-m 64:1024 -M 16:256'
+        run: |
+          script -e unit_tests_hg.log -c 'sh -x scripts/build/do_build.sh DEFS_EXTRA_OPTS="-DUNIT_TESTS -fPIE -fPIC"'
+          grep -E 'ok [0-9]+ - HG_MALLOC serves pkg and shm' unit_tests_hg.log | grep -q -v 'not ok'
+
+      - name: Run tests with HG_MALLOC_DBG
+        env:
+          MAKE_TGT: 'test'
+          UT_ALLOC: 'HG_MALLOC_DBG'
+          UT_MEM: '-m 64:1024 -M 16:256'
+        run: |
+          script -e unit_tests_hg_dbg.log -c 'sh -x scripts/build/do_build.sh DEFS_EXTRA_OPTS="-DUNIT_TESTS -fPIE -fPIC"'
+          grep -E 'ok [0-9]+ - HG_MALLOC serves pkg and shm' unit_tests_hg_dbg.log | grep -q -v 'not ok'
+
       - name: Collect test logs
         uses: actions/upload-artifact@v7
         with:
           name: unit_tests-logs_${{ matrix.os }}_${{ matrix.compiler }}
           path: |
             unit_tests.log
+            unit_tests_hg.log
+            unit_tests_hg_dbg.log
 
   all_done:
     needs: build_and_test
 
@@ -76,7 +76,7 @@
 #uuid= UUID generator | uuid-dev
 
 # Modules omitted from the default build, generally due to external dependencies.
-exclude_modules?= aaa_diameter aaa_radius auth_jwt auth_web3 b2b_logic_xml cachedb_cassandra cachedb_couchbase cachedb_dynamodb cachedb_memcached cachedb_mongodb cachedb_redis carrierroute cgrates compression cpl_c db_berkeley db_http db_mysql db_oracle db_perlvdb db_postgres db_sqlite db_unixodbc dialplan emergency event_rabbitmq event_kafka event_sqs h350 httpd http2d identity jabber json launch_darkly ldap lua mi_xmlrpc mmgeoip opentelemetry osp perl pi_http presence presence_dialoginfo presence_mwi presence_reginfo presence_xml presence_dfks proto_ipsec proto_sctp proto_tls proto_wss pua pua_bla pua_dialoginfo pua_mi pua_reginfo pua_usrloc pua_xmpp python regex rabbitmq_consumer rest_client rls rtp.io siprec sngtc snmpstats stir_shaken tls_mgm tls_openssl tls_wolfssl uuid xcap xcap_client xml xmpp
+exclude_modules?= aaa_diameter aaa_radius auth_jwt auth_web3 b2b_logic_xml cachedb_cassandra cachedb_couchbase cachedb_dynamodb cachedb_memcached cachedb_mongodb cachedb_redis carrierroute cgrates compression cpl_c db_berkeley db_http db_mysql db_oracle db_perlvdb db_postgres db_sqlite db_unixodbc dialplan emergency event_rabbitmq event_kafka event_sqs h350 hgstress httpd http2d identity jabber json launch_darkly ldap lua mi_xmlrpc mmgeoip opentelemetry osp perl pi_http presence presence_dialoginfo presence_mwi presence_reginfo presence_xml presence_dfks proto_ipsec proto_sctp proto_tls proto_wss pua pua_bla pua_dialoginfo pua_mi pua_reginfo pua_usrloc pua_xmpp python regex rabbitmq_consumer rest_client rls rtp.io siprec sngtc snmpstats stir_shaken tls_mgm tls_openssl tls_wolfssl uuid xcap xcap_client xml xmpp
 
 # Modules forced into the build, even when also listed in exclude_modules.
 include_modules?=
@@ -97,6 +97,12 @@ DEFS+= -DQ_MALLOC #Quality assurance memory allocator with runtime safety checks
 DEFS+= -DHP_MALLOC #High performance allocator with fine-grained locking
 DEFS+= -DDBG_MALLOC #Include additional, debug-enabled allocator flavors
 DEFS+= -DF_PARALLEL_MALLOC #Fast memory allocator with paralel buckets
+DEFS+= -DHG_MALLOC #Slab allocator with a lock-free fast path and elastic arenas
+# HG_MALLOC: select with -a HG_MALLOC. -m/-M accept INIT:CAP, e.g. -m 128:1024:
+# start at 128 MB, grow on demand up to 1 GB, give memory back when idle.
+# Uses huge pages when the host has them (hugetlb pool or THP), else 4 KB
+# pages. The committed arena is mlock()ed: run with LimitMEMLOCK=infinity.
+# See mem/README.hg_malloc.md
 #DEFS+= -DQM_DBG_MALLOC_HIST=3 #Size of debug history for Q_MALLOC (default is 1)
 #DEFS+= -DNO_DEBUG #Compile out all debug messages
 #DEFS+= -DNO_LOG #Compile out all logging
 
@@ -558,6 +558,9 @@ MKTAGS=ctags -R .
 #		decently fast allocator with extra sanity checks + safety buffers
 # -DHP_MALLOC
 #		high performance allocator optimized for shared memory multiprocessing
+# -DHG_MALLOC
+#		slab allocator with a lock-free fast path and elastic arenas
+#		(-m INIT:CAP), on huge pages when the host provides them
 # -DDBG_MALLOC
 #       will cause each of the enabled allocators to also include a "debugging"
 #       flavor of itself;  by running a debugging version of an allocator, you
 
@@ -6,6 +6,11 @@ endif
 
 .PHONY: test unit_tests system_tests
 
+# allocator and memory sizes the unit tests run with, e.g.
+#   make test UT_ALLOC=HG_MALLOC UT_MEM="-m 64:1024 -M 16:256"
+UT_ALLOC ?= HP_MALLOC
+UT_MEM ?=
+
 ifneq (,$(findstring UNIT_TESTS,$(DEFS)))
 include Makefile.openssl
 misclibs=lib/digest_auth/libdigest_auth.a
@@ -24,7 +29,7 @@ endif
 
 unit_tests: ensure_test_defs $(NAME)
 	-@echo "          =============   Start Unit Tests   ============="
-	./$(NAME) -dd -T $(module) -w . -a HP_MALLOC
+	./$(NAME) -dd -T $(module) -w . -a $(UT_ALLOC) $(UT_MEM)
 	-@echo "          ================================================"
 	-@echo "          ========   Passed All Tests! ᕦ(ò_óˇ)ᕤ   ========"
 	-@echo "          ================================================"
 
@@ -291,6 +291,18 @@ DB_DEFAULT_URL "db_default_url"
 DB_MAX_ASYNC_CONNECTIONS "db_max_async_connections"
 DISABLE_503_TRANSLATION "disable_503_translation"
 AUTO_SCALING_PROFILE "auto_scaling_profile"
+SHM_AUTO_SCALING_PROFILE "shm_auto_scaling_profile"
+PKG_AUTO_SCALING_PROFILE "pkg_auto_scaling_profile"
+HG_RAM_FLOOR_MB "hg_ram_floor_mb"
+HG_AUTOSCALE_DRY_RUN "hg_autoscale_dry_run"
+SHM_GROW_GRANULE "shm_grow_granule"
+PKG_GROW_GRANULE "pkg_grow_granule"
+HG_LOCK_STALL_US "hg_lock_stall_us"
+HG_GROW_AHEAD "hg_grow_ahead"
+HG_INTERIOR_RELEASE "hg_interior_release"
+HG_SCALING_CYCLE "hg_scaling_cycle"
+HG_SHRINK_STEP "hg_shrink_step"
+HG_MEM_CHECK "hg_mem_check"
 AUTO_SCALING_CYCLE "auto_scaling_cycle"
 TIMER_WORKERS "timer_workers"
 
@@ -546,6 +558,30 @@ SPACE		[ ]
 									return DISABLE_503_TRANSLATION; }
 <INITIAL>{AUTO_SCALING_PROFILE}	{	count(); yylval.strval=yytext;
 									return AUTO_SCALING_PROFILE; }
+<INITIAL>{SHM_AUTO_SCALING_PROFILE}	{	count(); yylval.strval=yytext;
+									return SHM_AUTO_SCALING_PROFILE; }
+<INITIAL>{PKG_AUTO_SCALING_PROFILE}	{	count(); yylval.strval=yytext;
+									return PKG_AUTO_SCALING_PROFILE; }
+<INITIAL>{HG_RAM_FLOOR_MB}	{	count(); yylval.strval=yytext;
+									return HG_RAM_FLOOR_MB; }
+<INITIAL>{HG_AUTOSCALE_DRY_RUN}	{	count(); yylval.strval=yytext;
+									return HG_AUTOSCALE_DRY_RUN; }
+<INITIAL>{SHM_GROW_GRANULE}	{	count(); yylval.strval=yytext;
+									return SHM_GROW_GRANULE; }
+<INITIAL>{PKG_GROW_GRANULE}	{	count(); yylval.strval=yytext;
+									return PKG_GROW_GRANULE; }
+<INITIAL>{HG_LOCK_STALL_US}	{	count(); yylval.strval=yytext;
+									return HG_LOCK_STALL_US; }
+<INITIAL>{HG_GROW_AHEAD}	{	count(); yylval.strval=yytext;
+									return HG_GROW_AHEAD; }
+<INITIAL>{HG_INTERIOR_RELEASE}	{	count(); yylval.strval=yytext;
+									return HG_INTERIOR_RELEASE; }
+<INITIAL>{HG_SCALING_CYCLE}	{	count(); yylval.strval=yytext;
+									return HG_SCALING_CYCLE; }
+<INITIAL>{HG_SHRINK_STEP}	{	count(); yylval.strval=yytext;
+									return HG_SHRINK_STEP; }
+<INITIAL>{HG_MEM_CHECK}	{	count(); yylval.strval=yytext;
+									return HG_MEM_CHECK; }
 <INITIAL>{AUTO_SCALING_CYCLE}	{	count(); yylval.strval=yytext;
 									return AUTO_SCALING_CYCLE; }
 <INITIAL>{TIMER_WORKERS}	{	count(); yylval.strval=yytext;
 
@@ -101,6 +101,7 @@
 #include "name_alias.h"
 #include "ut.h"
 #include "pt_scaling.h"
+#include <limits.h>
 #include "dset.h"
 #include "pvar.h"
 #include "blacklists.h"
@@ -197,6 +198,56 @@ union route_name_var {
 	void *data;
 } rn_tmp;
 
+/* A profile size number with an optional k/m/g suffix.  A suffix-less
+ * number passes through POSITIVE, keeping the profile's legacy unit
+ * (process count for the worker scaler, MB for the memory arenas); a
+ * suffixed number is normalized to KB and carried NEGATED, so the two
+ * kinds survive yacc's plain-int value stack without a union member the
+ * lexer's cfg.tab.h could not see the type of.  scale_suffix_kb() encodes,
+ * create_scaling_profile_units() decodes. */
+static long scale_suffix_kb(long num, const char *suf)
+{
+	if (!suf || !suf[0] || suf[1] || num <= 0)
+		return 0;
+	switch (suf[0]) {
+	case 'k': case 'K': return -num;
+	case 'm': case 'M':
+		return num > LONG_MAX / 1024 ? 0 : -(num * 1024);
+	case 'g': case 'G':
+		return num > LONG_MAX / (1024 * 1024) ? 0 :
+			-(num * 1024 * 1024);
+	}
+	return 0;
+}
+
+/* wraps create_auto_scaling_profile(): when either size carries a suffix
+ * (arrives negated, in KB), normalize BOTH to KB (a bare number is then
+ * read as MB) and flag the profile, so hg_autoscale_apply() knows the
+ * unit.  Suffix-less profiles take the untouched legacy path - the worker
+ * scaler never sees a change. */
+static int create_scaling_profile_units(char *name,
+		long up, int u_pct, int u_need, int u_win,
+		long down, int d_pct, int d_cyc, int d_delay)
+{
+	struct scaling_profile *p;
+	int kb = up < 0 || down < 0;
+
+	if (kb) {
+		up   = up < 0 ? -up : up * 1024;
+		down = down < 0 ? -down : down * 1024;
+	}
+	if (create_auto_scaling_profile(name, up, u_pct, u_need, u_win,
+	        down, d_pct, d_cyc, d_delay) < 0)
+		return -1;
+	if (kb) {
+		p = get_scaling_profile(name);
+		if (!p)
+			return -1;
+		p->mem_kb_units = 1;
+	}
+	return 0;
+}
+
 #ifndef SHM_EXTRA_STATS
 struct multi_str{
 	char *s;
@@ -408,6 +459,18 @@ extern int cfg_parse_only_routes;
 %token ASYNC_TOKEN
 %token LAUNCH_TOKEN
 %token AUTO_SCALING_PROFILE
+%token SHM_AUTO_SCALING_PROFILE
+%token PKG_AUTO_SCALING_PROFILE
+%token HG_RAM_FLOOR_MB
+%token HG_AUTOSCALE_DRY_RUN
+%token SHM_GROW_GRANULE
+%token PKG_GROW_GRANULE
+%token HG_LOCK_STALL_US
+%token HG_GROW_AHEAD
+%token HG_INTERIOR_RELEASE
+%token HG_SCALING_CYCLE
+%token HG_SHRINK_STEP
+%token HG_MEM_CHECK
 %token AUTO_SCALING_CYCLE
 %token TIMER_WORKERS
 
@@ -505,6 +568,7 @@ extern int cfg_parse_only_routes;
 %type <sockid> listen_id_def
 %type <sockid> phostport phostportrange
 %type <bondlst> socket_bond_elems
+%type <intval> scale_size
 %type <intval> proto port any_proto
 %type <strval> host_sep
 %type <intval> equalop compop matchop strop intop
@@ -925,32 +989,40 @@ mpath_def_list: mpath_def_list COLON STRING {IFOR(); add_mpath($3);}
 		| STRING { IFOR(); add_mpath($1);}
 		;
 
+scale_size:	  NUMBER { $$ = $1; }
+		| NUMBER ID {
+			$$ = scale_suffix_kb($1, $2);
+			if ($$ == 0)
+				yyerror("bad size suffix - use k, m or g");
+		}
+		;
+
 auto_scale_profile_def:
-		  ID SCALE_UP_TO NUMBER ON NUMBER MODULO FOR
+		  ID SCALE_UP_TO scale_size ON NUMBER MODULO FOR
 				NUMBER CYCLES_WITHIN NUMBER
-		  SCALE_DOWN_TO NUMBER ON NUMBER MODULO FOR
+		  SCALE_DOWN_TO scale_size ON NUMBER MODULO FOR
 				NUMBER CYCLES { IFOR();
-			if (create_auto_scaling_profile($1,$3,$5,$8,$10,
+			if (create_scaling_profile_units($1,$3,$5,$8,$10,
 			$12, $14, $17,10*$17)<0)
 				yyerror("failed to create auto scaling profile");
 		 }
-		| ID SCALE_UP_TO NUMBER ON NUMBER MODULO FOR
+		| ID SCALE_UP_TO scale_size ON NUMBER MODULO FOR
 				NUMBER CYCLES
-		  SCALE_DOWN_TO NUMBER ON NUMBER MODULO FOR
+		  SCALE_DOWN_TO scale_size ON NUMBER MODULO FOR
 				NUMBER CYCLES { IFOR();
-			if (create_auto_scaling_profile($1,$3,$5,$8,$8,
+			if (create_scaling_profile_units($1,$3,$5,$8,$8,
 			$11, $13, $16, 10*$16)<0)
 				yyerror("failed to create auto scaling profile");
 		 }
-		| ID SCALE_UP_TO NUMBER ON NUMBER MODULO FOR
+		| ID SCALE_UP_TO scale_size ON NUMBER MODULO FOR
 				NUMBER CYCLES_WITHIN NUMBER { IFOR();
-			if (create_auto_scaling_profile($1,$3,$5,$8,$10,
+			if (create_scaling_profile_units($1,$3,$5,$8,$10,
 			0, 0, 0, 0)<0)
 				yyerror("failed to create auto scaling profile");
 		}
-		| ID SCALE_UP_TO NUMBER ON NUMBER MODULO FOR
+		| ID SCALE_UP_TO scale_size ON NUMBER MODULO FOR
 				NUMBER CYCLES { IFOR();
-			if (create_auto_scaling_profile($1,$3,$5,$8,$8,
+			if (create_scaling_profile_units($1,$3,$5,$8,$8,
 			0, 0, 0, 0)<0)
 				yyerror("failed to create auto scaling profile");
 		}
@@ -1649,6 +1721,85 @@ assign_stm: LOGLEVEL EQUAL snumber { IFOR();
 		| AUTO_SCALING_PROFILE EQUAL error {
 				yyerror("bad auto-scaling profile definition");
 				}
+		| SHM_AUTO_SCALING_PROFILE EQUAL ID { IFOR();
+				hg_shm_profile_name=$3; }
+		| SHM_AUTO_SCALING_PROFILE EQUAL error {
+				yyerror("profile name expected");
+				}
+		| PKG_AUTO_SCALING_PROFILE EQUAL ID { IFOR();
+				hg_pkg_profile_name=$3; }
+		| PKG_AUTO_SCALING_PROFILE EQUAL error {
+				yyerror("profile name expected");
+				}
+		| HG_RAM_FLOOR_MB EQUAL NUMBER { IFOR();
+				hg_ram_floor_mb=$3; }
+		| HG_RAM_FLOOR_MB EQUAL error {
+				yyerror("integer value expected");
+				}
+		| HG_AUTOSCALE_DRY_RUN EQUAL NUMBER { IFOR();
+				hg_autoscale_dry_run=$3; }
+		| HG_AUTOSCALE_DRY_RUN EQUAL error {
+				yyerror("integer value expected");
+				}
+		| SHM_GROW_GRANULE EQUAL scale_size { IFOR();
+				/* scale_size: positive = MB, negated = KB */
+				hg_shm_grow_granule = $3 < 0 ?
+					(unsigned long)(-$3) << 10 :
+					(unsigned long)$3 << 20;
+				}
+		| SHM_GROW_GRANULE EQUAL error {
+				yyerror("size expected (number, optional k/m/g)");
+				}
+		| PKG_GROW_GRANULE EQUAL scale_size { IFOR();
+				hg_pkg_grow_granule = $3 < 0 ?
+					(unsigned long)(-$3) << 10 :
+					(unsigned long)$3 << 20;
+				}
+		| PKG_GROW_GRANULE EQUAL error {
+				yyerror("size expected (number, optional k/m/g)");
+				}
+		| HG_LOCK_STALL_US EQUAL NUMBER { IFOR();
+				hg_lock_stall_us=$3; }
+		| HG_LOCK_STALL_US EQUAL error {
+				yyerror("integer value expected");
+				}
+		| HG_GROW_AHEAD EQUAL NUMBER { IFOR();
+				hg_grow_ahead=$3; }
+		| HG_GROW_AHEAD EQUAL error {
+				yyerror("integer value expected");
+				}
+		| HG_INTERIOR_RELEASE EQUAL NUMBER { IFOR();
+				hg_interior_release=$3; }
+		| HG_INTERIOR_RELEASE EQUAL error {
+				yyerror("integer value expected");
+				}
+		| HG_SCALING_CYCLE EQUAL NUMBER { IFOR();
+				if ($3 < 1) {
+					yyerror("hg_scaling_cycle must be at least 1 second");
+					YYABORT;
+				}
+				hg_scaling_cycle=$3; }
+		| HG_SCALING_CYCLE EQUAL error {
+				yyerror("integer value expected");
+				}
+		| HG_SHRINK_STEP EQUAL scale_size { IFOR();
+				/* scale_size: positive = MB, negated = KB */
+				hg_shrink_step = $3 < 0 ?
+					(unsigned long)(-$3) << 10 :
+					(unsigned long)$3 << 20;
+				}
+		| HG_SHRINK_STEP EQUAL error {
+				yyerror("size expected (number, optional k/m/g)");
+				}
+		| HG_MEM_CHECK EQUAL NUMBER { IFOR();
+				if ($3 < 0 || $3 > 2) {
+					yyerror("hg_mem_check must be 0, 1 or 2");
+					YYABORT;
+				}
+				hg_mem_check=$3; }
+		| HG_MEM_CHECK EQUAL error {
+				yyerror("integer value expected");
+				}
 		| AUTO_SCALING_CYCLE EQUAL NUMBER { IFOR();
 				auto_scaling_cycle=$3; }
 		| AUTO_SCALING_CYCLE EQUAL error {