Bug 1726865 - Prefer using existing content processes for subframes during... (c38d0d17) · Commits · The Tor Project / Applications / Mullvad Browser

docshell/base/CanonicalBrowsingContext.cpp

+4 −1

Original line number	Diff line number	Diff line
		@@ -1858,11 +1858,14 @@ CanonicalBrowsingContext::ChangeRemoteness(
		BrowsingContextGroup* finalGroup =
		aOptions.mReplaceBrowsingContext ? change->mSpecificGroup.get() : Group();

		bool preferUsed =
		StaticPrefs::browser_tabs_remote_subframesPreferUsed() && !IsTop();

		change->mContentParent = ContentParent::GetNewOrUsedLaunchingBrowserProcess(
		/* aRemoteType = */ aOptions.mRemoteType,
		/* aGroup = */ finalGroup,
		/* aPriority = */ hal::PROCESS_PRIORITY_FOREGROUND,
		/* aPreferUsed = */ false);
		/* aPreferUsed = */ preferUsed);
		if (!change->mContentParent) {
		change->Cancel(NS_ERROR_FAILURE);
		return promise.forget();

dom/ipc/ContentParent.cpp

+3 −2

Original line number	Diff line number	Diff line
		@@ -918,8 +918,9 @@ already_AddRefed<ContentParent> ContentParent::GetUsedBrowserProcess(
		}

		if (aPreferUsed && numberOfParents) {
		// For the preloaded browser we don't want to create a new process but
		// reuse an existing one.
		// If we prefer re-using existing content processes, we don't want to create
		// a new process, and instead re-use an existing one, so pretend the process
		// limit is at the current number of processes.
		aMaxContentParents = numberOfParents;
		}

dom/ipc/tests/browser.ini

+2 −0

Original line number	Diff line number	Diff line
		@@ -40,3 +40,5 @@ skip-if =
		[browser_very_fission.js]
		support-files = file_dummy.html
		run-if = widget == "gtk"
		[browser_subframesPreferUsed.js]
		skip-if = !fission # Test doesn't make sense without fission

dom/ipc/tests/browser_subframesPreferUsed.js

0 → 100644

+82 −0

Original line number	Diff line number	Diff line
		/* Any copyright is dedicated to the Public Domain.
		http://creativecommons.org/publicdomain/zero/1.0/ */

		ok(
		Services.appinfo.fissionAutostart,
		"this test requires fission to function!"
		);

		function documentURL(origin, html) {
		let params = new URLSearchParams();
		params.append("html", html.trim());
		return `${origin}/document-builder.sjs?${params.toString()}`;
		}

		async function singleTest(preferUsed) {
		info(`running test with preferUsed=${preferUsed}`);
		await SpecialPowers.pushPrefEnv({
		set: [
		["dom.ipc.processCount.webIsolated", 4],
		["browser.tabs.remote.subframesPreferUsed", preferUsed],
		],
		});

		const TEST_URL = documentURL(
		"https://example.com",
		`<iframe src=${JSON.stringify(
		documentURL("https://example.org", `<h1>iframe</h1>`)
		)}></iframe>`
		);

		await BrowserTestUtils.withNewTab(TEST_URL, async browser1 => {
		is(browser1.browsingContext.children.length, 1);
		let topProc1 = browser1.browsingContext.currentWindowGlobal.domProcess;
		let frameProc1 =
		browser1.browsingContext.children[0].currentWindowGlobal.domProcess;
		isnot(
		topProc1.childID,
		frameProc1.childID,
		"the frame should be in a separate process"
		);

		await BrowserTestUtils.withNewTab(TEST_URL, async browser2 => {
		is(browser2.browsingContext.children.length, 1);
		let topProc2 = browser2.browsingContext.currentWindowGlobal.domProcess;
		let frameProc2 =
		browser2.browsingContext.children[0].currentWindowGlobal.domProcess;
		isnot(
		topProc2.childID,
		frameProc2.childID,
		"the frame should be in a separate process"
		);

		// Compare processes used for the two tabs.
		isnot(
		topProc1.childID,
		topProc2.childID,
		"the toplevel windows should be loaded in separate processes"
		);
		if (preferUsed) {
		is(
		frameProc1.childID,
		frameProc2.childID,
		"the iframes should load in the same process with subframesPreferUsed"
		);
		} else {
		isnot(
		frameProc1.childID,
		frameProc2.childID,
		"the iframes should load in different processes without subframesPreferUsed"
		);
		}
		});
		});
		}

		add_task(async function test_preferUsed() {
		await singleTest(true);
		});

		add_task(async function test_noPreferUsed() {
		await singleTest(false);
		});

modules/libpref/init/StaticPrefList.yaml

+9 −0

Original line number	Diff line number	Diff line
		@@ -1350,6 +1350,15 @@
		value: false
		mirror: always

		# Whether or not process selection for subframes will prefer re-using an
		# existing content process over creating a new one. Enabling this pref should
		# reduce the number of processes allocated for non-first-party domains if
		# dom.ipc.processCount.webIsolated > 1.
		- name: browser.tabs.remote.subframesPreferUsed
		type: bool
		value: true
		mirror: always

		# When this pref is enabled, opaque response is only allowed to enter the
		# content process if it's a response for media (audio, image, video), CSS, or
		# JavaScript.