ec8529652d
This disarms a footgun in the FreezableMapping::Freeze API, which was causing read-only mappings in the global stylesheet cache to fail. These failures caused content processes to re-load the style sheets, increasing memory usage. Differential Revision: https://phabricator.services.mozilla.com/D240928
100 lines
3.1 KiB
C++
100 lines
3.1 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "XPCSelfHostedShmem.h"
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#include "xpcprivate.h"
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// static
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mozilla::StaticRefPtr<xpc::SelfHostedShmem>
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xpc::SelfHostedShmem::sSelfHostedXdr;
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NS_IMPL_ISUPPORTS(xpc::SelfHostedShmem, nsIMemoryReporter)
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// static
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xpc::SelfHostedShmem& xpc::SelfHostedShmem::GetSingleton() {
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MOZ_ASSERT_IF(!sSelfHostedXdr, NS_IsMainThread());
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if (!sSelfHostedXdr) {
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sSelfHostedXdr = new SelfHostedShmem;
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}
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return *sSelfHostedXdr;
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}
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void xpc::SelfHostedShmem::InitMemoryReporter() {
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mozilla::RegisterWeakMemoryReporter(this);
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}
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// static
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void xpc::SelfHostedShmem::Shutdown() {
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MOZ_ASSERT(NS_IsMainThread());
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// NOTE: We cannot call UnregisterWeakMemoryReporter(sSelfHostedXdr) as the
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// service is shutdown at the time this call is made. In any cases, this would
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// already be done when the memory reporter got destroyed.
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sSelfHostedXdr = nullptr;
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}
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void xpc::SelfHostedShmem::InitFromParent(ContentType aXdr) {
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MOZ_ASSERT(XRE_IsParentProcess());
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MOZ_ASSERT(NS_IsMainThread());
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MOZ_ASSERT(!mHandle && !mMem, "Shouldn't call this more than once");
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size_t len = aXdr.Length();
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auto handle = mozilla::ipc::shared_memory::CreateFreezable(len);
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if (NS_WARN_IF(!handle)) {
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return;
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}
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auto mapping = std::move(handle).Map();
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if (NS_WARN_IF(!mapping)) {
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return;
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}
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void* address = mapping.Address();
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memcpy(address, aXdr.Elements(), aXdr.LengthBytes());
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mHandle = std::move(mapping).Freeze();
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mMem = mHandle.Map();
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}
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bool xpc::SelfHostedShmem::InitFromChild(
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mozilla::ipc::ReadOnlySharedMemoryHandle aHandle) {
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MOZ_ASSERT(!XRE_IsParentProcess());
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MOZ_ASSERT(NS_IsMainThread());
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MOZ_ASSERT(!mMem, "Shouldn't call this more than once");
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mMem = aHandle.Map();
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return mMem.IsValid();
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}
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xpc::SelfHostedShmem::ContentType xpc::SelfHostedShmem::Content() const {
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if (!mMem) {
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return ContentType();
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}
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return mMem.DataAsSpan<uint8_t>();
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}
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const mozilla::ipc::ReadOnlySharedMemoryHandle& xpc::SelfHostedShmem::Handle()
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const {
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return mHandle;
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}
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NS_IMETHODIMP
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xpc::SelfHostedShmem::CollectReports(nsIHandleReportCallback* aHandleReport,
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nsISupports* aData, bool aAnonymize) {
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// If this is the parent process, then we have a handle and this instance owns
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// the data and shares it with other processes, otherwise this is shared data.
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if (XRE_IsParentProcess()) {
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// This does not exactly report the amount of data mapped by the system,
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// but the space requested when creating the handle.
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MOZ_COLLECT_REPORT("explicit/js-non-window/shared-memory/self-hosted-xdr",
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KIND_NONHEAP, UNITS_BYTES, mMem.Size(),
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"Memory used to initialize the JS engine with the "
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"self-hosted code encoded by the parent process.");
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}
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return NS_OK;
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}
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