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src: initial enablement of IsolateGroups · nodejs/node@ec53d9f · GitHub

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jasnell
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aduh95
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src: initial enablement of IsolateGroups
This lays the initial groundwork for enabling the use of IsolateGroups. Every isolate in V8 is created within a group. When pointer compression is enabled, all isolates within a single group are limited to a 4 GB shared pointer cage. By default, all isolates in the process share the same group, which means that when running with pointer compression, the entire process would be limited to a single 4 GB shared pointer cage. But, we can create as many IsolateGroups as we want, limited only by the amount of virtual memory available on the machine. PR-URL: #60254 Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Stephen Belanger <admin@stephenbelanger.com> Reviewed-By: Michaël Zasso <targos@protonmail.com>
1 parent c95d974 commit ec53d9f

8 files changed

Lines changed: 62 additions & 4 deletions

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‎common.gypi‎

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Original file line numberDiff line numberDiff line change
@@ -446,6 +446,9 @@
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['v8_enable_pointer_compression == 1', {
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'defines': ['V8_COMPRESS_POINTERS'],
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}],
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['v8_enable_pointer_compression == 1 and v8_enable_pointer_compression_shared_cage != 1', {
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'defines': ['V8_COMPRESS_POINTERS_IN_MULTIPLE_CAGES'],
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}],
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['v8_enable_pointer_compression_shared_cage == 1', {
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'defines': ['V8_COMPRESS_POINTERS_IN_SHARED_CAGE'],
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}],

‎configure.py‎

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@@ -646,6 +646,12 @@
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default=None,
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help='[Experimental] Enable V8 pointer compression (limits max heap to 4GB and breaks ABI compatibility)')
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parser.add_argument('--experimental-pointer-compression-shared-cage',
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action='store_true',
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dest='pointer_compression_shared_cage',
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default=None,
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help='[Experimental] Use V8 pointer compression with shared cage (requires --experimental-enable-pointer-compression)')
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parser.add_argument('--v8-options',
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action='store',
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dest='v8_options',
@@ -1731,7 +1737,10 @@ def configure_v8(o, configs):
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# Note that enabling pointer compression without enabling sandbox is unsupported by V8,
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# so this can be broken at any time.
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o['variables']['v8_enable_sandbox'] = 0
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o['variables']['v8_enable_pointer_compression_shared_cage'] = 1 if options.enable_pointer_compression else 0
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# We set v8_enable_pointer_compression_shared_cage to 0 always, even when
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# pointer compression is enabled so that we don't accidentally enable shared
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# cage mode when pointer compression is on.
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o['variables']['v8_enable_pointer_compression_shared_cage'] = 1 if options.pointer_compression_shared_cage else 0
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o['variables']['v8_enable_external_code_space'] = 1 if options.enable_pointer_compression else 0
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o['variables']['v8_enable_31bit_smis_on_64bit_arch'] = 1 if options.enable_pointer_compression else 0
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o['variables']['v8_enable_extensible_ro_snapshot'] = 0

‎src/api/embed_helpers.cc‎

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@@ -1,6 +1,7 @@
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#include "debug_utils-inl.h"
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#include "env-inl.h"
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#include "node.h"
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#include "node_internals.h"
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#include "node_snapshot_builder.h"
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using v8::Context;
@@ -127,7 +128,7 @@ CommonEnvironmentSetup::CommonEnvironmentSetup(
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if (flags & Flags::kIsForSnapshotting) {
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// The isolate must be registered before the SnapshotCreator initializes the
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// isolate, so that the memory reducer can be initialized.
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isolate = impl_->isolate = Isolate::Allocate();
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isolate = impl_->isolate = Isolate::Allocate(GetOrCreateIsolateGroup());
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platform->RegisterIsolate(isolate, loop);
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impl_->snapshot_creator.emplace(isolate, params);

‎src/api/environment.cc‎

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Original file line numberDiff line numberDiff line change
@@ -37,6 +37,7 @@ using v8::Function;
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using v8::FunctionCallbackInfo;
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using v8::HandleScope;
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using v8::Isolate;
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using v8::IsolateGroup;
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using v8::Just;
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using v8::JustVoid;
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using v8::Local;
@@ -304,14 +305,26 @@ void SetIsolateUpForNode(v8::Isolate* isolate) {
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SetIsolateUpForNode(isolate, settings);
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}
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//
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IsolateGroup GetOrCreateIsolateGroup() {
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// When pointer compression is disabled, we cannot create new groups,
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// in which case we'll always return the default.
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if (IsolateGroup::CanCreateNewGroups()) {
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return IsolateGroup::Create();
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}
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return IsolateGroup::GetDefault();
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}
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// TODO(joyeecheung): we may want to expose this, but then we need to be
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// careful about what we override in the params.
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Isolate* NewIsolate(Isolate::CreateParams* params,
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uv_loop_t* event_loop,
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MultiIsolatePlatform* platform,
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const SnapshotData* snapshot_data,
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const IsolateSettings& settings) {
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Isolate* isolate = Isolate::Allocate();
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IsolateGroup group = GetOrCreateIsolateGroup();
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Isolate* isolate = Isolate::Allocate(group);
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if (isolate == nullptr) return nullptr;
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if (snapshot_data != nullptr) {

‎src/node_internals.h‎

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@@ -56,6 +56,9 @@ extern uint64_t node_start_time;
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// Forward declaration
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class Environment;
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static constexpr uint64_t kMaxPointerCompressionHeap = uint64_t{1}
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<< 32; // 4 GiB
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// Convert a struct sockaddr to a { address: '1.2.3.4', port: 1234 } JS object.
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// Sets address and port properties on the info object and returns it.
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// If |info| is omitted, a new object is returned.
@@ -341,6 +344,20 @@ void TraceEnvVar(Environment* env,
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v8::Local<v8::String> key);
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void DefineZlibConstants(v8::Local<v8::Object> target);
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// If creating new v8::IsolateGroup instance is supported, this returns a
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// new instance. Otherwise, it returns the default instance.
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//
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// An IsolateGroup is a collection of Isolates that share the same underlying
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// pointer cage when pointer compression is enabled. When pointer compression is
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// disabled, there is a default IsolateGroup that is used for all isolates, and
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// when pointer compression is enabled, all isolates in the app share the
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// same pointer cage by default that is limited a maximum of 4GB, not counting
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// array buffers and off-heap storage. Multiple IsolateGroups can be used to
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// work around the 4GB limit, but each group reserves a range of virtual memory
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// addresses, so this should be used with care.
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v8::IsolateGroup GetOrCreateIsolateGroup();
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v8::Isolate* NewIsolate(v8::Isolate::CreateParams* params,
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uv_loop_t* event_loop,
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MultiIsolatePlatform* platform,

‎src/node_options.cc‎

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@@ -127,7 +127,15 @@ void PerIsolateOptions::HandleMaxOldSpaceSizePercentage(
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}
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// Get available memory in bytes
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#ifdef V8_COMPRESS_POINTERS
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// When pointer compression is enabled, V8 uses a 4 GiB heap limit.
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// We'll use the smaller of that or the total system memory as
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// reported by uv.
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uint64_t total_memory =
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std::min(uv_get_total_memory(), kMaxPointerCompressionHeap); // 4 GiB
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#else
130137
uint64_t total_memory = uv_get_total_memory();
138+
#endif
131139
uint64_t constrained_memory = uv_get_constrained_memory();
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133141
// Use constrained memory if available, otherwise use total memory

‎test/parallel/test-max-old-space-size-percentage.js‎

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@@ -122,7 +122,11 @@ assert(
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);
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// Validate heap sizes against system memory
125-
const totalMemoryMB = Math.floor(os.totalmem() / 1024 / 1024);
125+
// When pointer compression is enabled, the maximum total memory is 4 GB
126+
const totalmem = Math.floor(os.totalmem() / 1024 / 1024);
127+
const totalMemoryMB = process.config.variables.v8_enable_pointer_compression ?
128+
Math.min(4096, totalmem) :
129+
totalmem;
126130
const uint64Max = 2 ** 64 - 1;
127131
const constrainedMemory = process.constrainedMemory();
128132
const constrainedMemoryMB = Math.floor(constrainedMemory / 1024 / 1024);

‎tools/v8_gypfiles/features.gypi‎

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@@ -367,6 +367,9 @@
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['v8_enable_pointer_compression==1', {
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'defines': ['V8_COMPRESS_POINTERS'],
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}],
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['v8_enable_pointer_compression==1 and v8_enable_pointer_compression_shared_cage!=1', {
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'defines': ['V8_COMPRESS_POINTERS_IN_MULTIPLE_CAGES'],
372+
}],
370373
['v8_enable_pointer_compression_shared_cage==1', {
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'defines': ['V8_COMPRESS_POINTERS_IN_SHARED_CAGE'],
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}],

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