From d3857d488866f5f10c0c95b4699a20f83902b76a Mon Sep 17 00:00:00 2001
From: Paul Bone <pbone@mozilla.com>
Date: Mon, 6 May 2019 03:14:22 +0000
Subject: [PATCH] Bug 1532838 - Add a pref for the minimum nursery size r=mccr8

Differential Revision: https://phabricator.services.mozilla.com/D29815

--HG--
extra : moz-landing-system : lando
---
 dom/base/nsJSEnvironment.cpp | 9 ++++++---
 js/public/GCAPI.h            | 2 +-
 modules/libpref/init/all.js  | 4 +++-
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/dom/base/nsJSEnvironment.cpp b/dom/base/nsJSEnvironment.cpp
index 23ffde9a0eb5..9b53e65d1cd8 100644
--- a/dom/base/nsJSEnvironment.cpp
+++ b/dom/base/nsJSEnvironment.cpp
@@ -2355,8 +2355,8 @@ static void SetMemoryPrefChangedCallbackMB(const char* aPrefName,
   }
 }
 
-static void SetMemoryNurseryMaxPrefChangedCallback(const char* aPrefName,
-                                                   void* aClosure) {
+static void SetMemoryNurseryPrefChangedCallback(const char* aPrefName,
+                                                void* aClosure) {
   int32_t prefKB = Preferences::GetInt(aPrefName, -1);
   // handle overflow and negative pref values
   CheckedInt<int32_t> prefB = CheckedInt<int32_t>(prefKB) * 1024;
@@ -2511,7 +2511,10 @@ void nsJSContext::EnsureStatics() {
   Preferences::RegisterCallbackAndCall(SetMemoryPrefChangedCallbackMB,
                                        "javascript.options.mem.max",
                                        (void*)JSGC_MAX_BYTES);
-  Preferences::RegisterCallbackAndCall(SetMemoryNurseryMaxPrefChangedCallback,
+  Preferences::RegisterCallbackAndCall(SetMemoryNurseryPrefChangedCallback,
+                                       "javascript.options.mem.nursery.min_kb",
+                                       (void*)JSGC_MIN_NURSERY_BYTES);
+  Preferences::RegisterCallbackAndCall(SetMemoryNurseryPrefChangedCallback,
                                        "javascript.options.mem.nursery.max_kb",
                                        (void*)JSGC_MAX_NURSERY_BYTES);
 
diff --git a/js/public/GCAPI.h b/js/public/GCAPI.h
index 6cd6a0167d13..69a0e495358f 100644
--- a/js/public/GCAPI.h
+++ b/js/public/GCAPI.h
@@ -303,7 +303,7 @@ typedef enum JSGCParamKey {
    * gc::ChunkSize, otherwise it'll be rounded to the nearest gc::ChunkSize.
    *
    * Default: Nursery::SubChunkLimit
-   * Pref: None
+   * Pref: javascript.options.mem.nursery.min_kb
    */
   JSGC_MIN_NURSERY_BYTES = 31,
 
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index dde9283f216d..4ff3ea7c17c4 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1479,10 +1479,12 @@ pref("javascript.options.mem.high_water_mark", 128);
 // cannot be represented directly in order to show it in about:config.
 pref("javascript.options.mem.max", -1);
 
-// JSGC_MAX_NURSERY_BYTES
+// JSGC_MIN_NURSERY_BYTES / JSGC_MAX_NURSERY_BYTES
 #if defined(ANDROID) || defined(XP_IOS)
+pref("javascript.options.mem.nursery.min_kb", 192);
 pref("javascript.options.mem.nursery.max_kb", 4096);
 #else
+pref("javascript.options.mem.nursery.min_kb", 192);
 pref("javascript.options.mem.nursery.max_kb", 16384);
 #endif