Improve performance of jemalloc svelte config.android-cts_7.1_r1android-cts-7.1_r9android-cts-7.1_r8android-cts-7.1_r7android-cts-7.1_r6android-cts-7.1_r5android-cts-7.1_r4android-cts-7.1_r3android-cts-7.1_r29android-cts-7.1_r28android-cts-7.1_r27android-cts-7.1_r26android-cts-7.1_r25android-cts-7.1_r24android-cts-7.1_r23android-cts-7.1_r22android-cts-7.1_r21android-cts-7.1_r20android-cts-7.1_r2android-cts-7.1_r19android-cts-7.1_r18android-cts-7.1_r17android-cts-7.1_r16android-cts-7.1_r15android-cts-7.1_r14android-cts-7.1_r13android-cts-7.1_r12android-cts-7.1_r11android-cts-7.1_r10android-cts-7.1_r1android-7.1.2_r9android-7.1.2_r8android-7.1.2_r6android-7.1.2_r5android-7.1.2_r4android-7.1.2_r39android-7.1.2_r38android-7.1.2_r37android-7.1.2_r36android-7.1.2_r33android-7.1.2_r32android-7.1.2_r30android-7.1.2_r3android-7.1.2_r29android-7.1.2_r28android-7.1.2_r27android-7.1.2_r25android-7.1.2_r24android-7.1.2_r23android-7.1.2_r2android-7.1.2_r19android-7.1.2_r18android-7.1.2_r17android-7.1.2_r16android-7.1.2_r15android-7.1.2_r14android-7.1.2_r13android-7.1.2_r12android-7.1.2_r11android-7.1.2_r10android-7.1.2_r1android-7.1.1_r9android-7.1.1_r8android-7.1.1_r7android-7.1.1_r61android-7.1.1_r60android-7.1.1_r6android-7.1.1_r59android-7.1.1_r58android-7.1.1_r57android-7.1.1_r56android-7.1.1_r55android-7.1.1_r54android-7.1.1_r53android-7.1.1_r52android-7.1.1_r51android-7.1.1_r50android-7.1.1_r49android-7.1.1_r48android-7.1.1_r47android-7.1.1_r46android-7.1.1_r45android-7.1.1_r44android-7.1.1_r43android-7.1.1_r42android-7.1.1_r41android-7.1.1_r40android-7.1.1_r4android-7.1.1_r39android-7.1.1_r38android-7.1.1_r35android-7.1.1_r33android-7.1.1_r32android-7.1.1_r31android-7.1.1_r3android-7.1.1_r28android-7.1.1_r27android-7.1.1_r26android-7.1.1_r25android-7.1.1_r24android-7.1.1_r23android-7.1.1_r22android-7.1.1_r21android-7.1.1_r20android-7.1.1_r2android-7.1.1_r17android-7.1.1_r16android-7.1.1_r15android-7.1.1_r14android-7.1.1_r13android-7.1.1_r12android-7.1.1_r11android-7.1.1_r10android-7.1.1_r1android-7.1.0_r7android-7.1.0_r6android-7.1.0_r5android-7.1.0_r4android-7.1.0_r3android-7.1.0_r2android-7.1.0_r1nougat-mr2.3-releasenougat-mr2.2-releasenougat-mr2.1-releasenougat-mr2-security-releasenougat-mr2-releasenougat-mr2-pixel-releasenougat-mr2-devnougat-mr1.8-releasenougat-mr1.7-releasenougat-mr1.6-releasenougat-mr1.5-releasenougat-mr1.4-releasenougat-mr1.3-releasenougat-mr1.2-releasenougat-mr1.1-releasenougat-mr1-volantis-releasenougat-mr1-security-releasenougat-mr1-releasenougat-mr1-flounder-releasenougat-mr1-devnougat-mr1-cts-releasenougat-dr1-release

Change the decay time from zero to one second, to avoid problems with
the purge interferring with allocations taking too long.

Also, decrease the arenas from 2 to 1 for the svelte config to offset
the PSS increase caused by the decay time change.

Bug: 30077848
Change-Id: Ie7688a8bfd50f0ba7d5f0e594a37baca43596e41

3 files changed, 27 insertions, 18 deletions

diff --git a/Android.bp b/Android.bp
index 18a1e6a..a6ab9dc 100644
--- a/Android.bp
+++ b/Android.bp
@@ -23,8 +23,6 @@ common_cflags = [
 ]
 
 // These parameters change the way jemalloc works.
-//   ANDROID_ALWAYS_PURGE
-//     If defined, always purge immediately when a page is purgeable.
 //   ANDROID_MAX_ARENAS=XX
 //     The total number of arenas will be less than or equal to this number.
 //     The number of arenas will be calculated as 2 * the number of cpus
@@ -43,11 +41,11 @@ common_cflags = [
 //     1 << XX is the default chunk size used by the system. Decreasing this
 //     usually decreases the amount of PSS used, but can increase
 //     fragmentation.
+
+// Default to a single arena for svelte configurations to minimize
+// PSS consumed by jemalloc.
 common_cflags += [
-    "-DANDROID_ALWAYS_PURGE",
-    "-DANDROID_MAX_ARENAS=2",
-    "-DANDROID_TCACHE_NSLOTS_SMALL_MAX=8",
-    "-DANDROID_TCACHE_NSLOTS_LARGE=16",
+    "-DANDROID_MAX_ARENAS=1",
     "-DANDROID_LG_TCACHE_MAXCLASS_DEFAULT=16",
 ]
 
@@ -59,7 +57,13 @@ common_c_local_includes = [
 common_product_variables = {
     // Only enable the tcache on non-svelte configurations, to save PSS.
     malloc_not_svelte: {
-        cflags: ["-DJEMALLOC_TCACHE"],
+        cflags: [
+            "-UANDROID_MAX_ARENAS",
+            "-DANDROID_MAX_ARENAS=2",
+            "-DJEMALLOC_TCACHE",
+            "-DANDROID_TCACHE_NSLOTS_SMALL_MAX=8",
+            "-DANDROID_TCACHE_NSLOTS_LARGE=16",
+        ],
     },
 }
 
diff --git a/Android.mk b/Android.mk
index 43cb8a1..34f2681 100644
--- a/Android.mk
+++ b/Android.mk
@@ -24,8 +24,6 @@ jemalloc_common_cflags := \
 	-Wno-type-limits \
 
 # These parameters change the way jemalloc works.
-#   ANDROID_ALWAYS_PURGE
-#     If defined, always purge immediately when a page is purgeable.
 #   ANDROID_MAX_ARENAS=XX
 #     The total number of arenas will be less than or equal to this number.
 #     The number of arenas will be calculated as 2 * the number of cpus
@@ -45,16 +43,22 @@ jemalloc_common_cflags := \
 #     usually decreases the amount of PSS used, but can increase
 #     fragmentation.
 jemalloc_common_cflags += \
-	-DANDROID_ALWAYS_PURGE \
-	-DANDROID_MAX_ARENAS=2 \
-	-DANDROID_TCACHE_NSLOTS_SMALL_MAX=8 \
-	-DANDROID_TCACHE_NSLOTS_LARGE=16 \
 	-DANDROID_LG_TCACHE_MAXCLASS_DEFAULT=16 \
 
+ifeq ($(MALLOC_SVELTE),true)
+# Use a single arena on svelte devices to keep the PSS consumption as low
+# as possible.
+jemalloc_common_cflags += \
+	-DANDROID_MAX_ARENAS=1 \
+
+else
 # Only enable the tcache on non-svelte configurations, to save PSS.
-ifneq ($(MALLOC_SVELTE),true)
 jemalloc_common_cflags += \
-	-DJEMALLOC_TCACHE
+	-DANDROID_MAX_ARENAS=2 \
+	-DJEMALLOC_TCACHE \
+	-DANDROID_TCACHE_NSLOTS_SMALL_MAX=8 \
+	-DANDROID_TCACHE_NSLOTS_LARGE=16 \
+
 endif
 
 # Use a 512K chunk size on 32 bit systems.
diff --git a/include/jemalloc/internal/arena.h b/include/jemalloc/internal/arena.h
index f234ec6..47096b4 100644
--- a/include/jemalloc/internal/arena.h
+++ b/include/jemalloc/internal/arena.h
@@ -30,12 +30,13 @@ typedef enum {
 	purge_mode_limit = 2
 } purge_mode_t;
 /* ANDROID change */
-/* Use the decay mode purge method. By setting the DECAY_TIME_DEFAULT to
- * zero, this forces all pages to be purged as soon as they are not in use.
+/* Use the decay mode purge method. Do not set this value to zero, since
+ * forcing a purge immediately affects performance negatively. Using a
+ * small value provides a compromise between performance and extra PSS.
  */
 #define	PURGE_DEFAULT		purge_mode_decay
 /* Default decay time in seconds. */
-#define	DECAY_TIME_DEFAULT	0
+#define	DECAY_TIME_DEFAULT	1
 /* End ANDROID change */
 /* Number of event ticks between time checks. */
 #define	DECAY_NTICKS_PER_UPDATE	1000