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content / browser / renderer_host / spare_render_process_host_manager_impl.cc [blame]
// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/renderer_host/spare_render_process_host_manager_impl.h"
#include "base/check.h"
#include "base/debug/dump_without_crashing.h"
#include "base/memory/memory_pressure_monitor.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/no_destructor.h"
#include "content/browser/renderer_host/render_process_host_impl.h"
#include "content/browser/site_instance_impl.h"
#include "content/common/features.h"
#include "content/public/browser/browser_context.h"
#include "content/public/browser/browser_main_runner.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/common/content_client.h"
#include "content/public/common/content_features.h"
namespace content {
SpareRenderProcessHostManagerImpl::SpareRenderProcessHostManagerImpl() =
default;
SpareRenderProcessHostManagerImpl::~SpareRenderProcessHostManagerImpl() =
default;
// static
SpareRenderProcessHostManager& SpareRenderProcessHostManager::Get() {
return SpareRenderProcessHostManagerImpl::Get();
}
// static
SpareRenderProcessHostManagerImpl& SpareRenderProcessHostManagerImpl::Get() {
static base::NoDestructor<SpareRenderProcessHostManagerImpl> s_instance;
return *s_instance;
}
void SpareRenderProcessHostManagerImpl::StartDestroyTimer(
std::optional<base::TimeDelta> timeout) {
if (!timeout) {
return;
}
deferred_destroy_timer_.Start(
FROM_HERE, timeout.value(),
base::BindOnce(&SpareRenderProcessHostManagerImpl::CleanupSpares,
base::Unretained(this)));
}
bool SpareRenderProcessHostManagerImpl::DestroyTimerWillFireBefore(
base::TimeDelta timeout) {
return deferred_destroy_timer_.IsRunning() &&
deferred_destroy_timer_.GetCurrentDelay() < timeout;
}
void SpareRenderProcessHostManagerImpl::AddObserver(Observer* observer) {
observer_list_.AddObserver(observer);
}
void SpareRenderProcessHostManagerImpl::RemoveObserver(Observer* observer) {
observer_list_.RemoveObserver(observer);
}
void SpareRenderProcessHostManagerImpl::WarmupSpare(
BrowserContext* browser_context) {
WarmupSpare(browser_context, std::nullopt);
}
const std::vector<RenderProcessHost*>&
SpareRenderProcessHostManagerImpl::GetSpares() {
return spare_rphs_;
}
std::vector<int> SpareRenderProcessHostManagerImpl::GetSpareIds() {
std::vector<int> spare_ids;
spare_ids.reserve(spare_rphs_.size());
for (RenderProcessHost* spare_rph : spare_rphs_) {
spare_ids.push_back(spare_rph->GetID());
}
return spare_ids;
}
void SpareRenderProcessHostManagerImpl::CleanupSparesForTesting() {
CleanupSpares();
}
void SpareRenderProcessHostManagerImpl::WarmupSpare(
BrowserContext* browser_context,
std::optional<base::TimeDelta> timeout) {
if (delay_timer_) {
// If the timeout does not have a value, the delayed creation is no longer
// required since we will create the spare renderer here.
// Otherwise we will create the spare renderer and have the delayed creation
// override the timeout later on.
if (!timeout.has_value()) {
UMA_HISTOGRAM_TIMES("BrowserRenderProcessHost.SpareProcessDelayTime",
delay_timer_->Elapsed());
delay_timer_.reset();
}
}
// Check if there's already an existing, matching, spare.
RenderProcessHost* spare_rph =
!spare_rphs_.empty() ? spare_rphs_[0] : nullptr;
if (spare_rph && spare_rph->GetBrowserContext() == browser_context) {
DCHECK_EQ(browser_context->GetDefaultStoragePartition(),
spare_rph->GetStoragePartition());
// Use the new timeout if the specified timeout will be triggered after the
// current timeout (or not triggered at all).
if (!timeout.has_value() || DestroyTimerWillFireBefore(timeout.value())) {
deferred_destroy_timer_.Stop();
StartDestroyTimer(timeout);
}
return;
}
bool had_spare_renderer = !!spare_rph;
CleanupSpares();
UMA_HISTOGRAM_BOOLEAN(
"BrowserRenderProcessHost.SpareProcessEvictedOtherSpare",
had_spare_renderer);
// Don't create a spare renderer for a BrowserContext that is in the
// process of shutting down.
if (browser_context->ShutdownStarted()) {
// Create a crash dump to help us assess what scenarios trigger this
// path to be taken.
// TODO(acolwell): Remove this call once are confident we've eliminated
// any problematic callers.
base::debug::DumpWithoutCrashing();
return;
}
if (BrowserMainRunner::ExitedMainMessageLoop()) {
// Don't create a new process when the browser is shutting down. No
// DumpWithoutCrashing here since there are known cases in the wild. See
// https://crbug.com/40274462 for details.
return;
}
// Don't create a spare renderer if we're using --single-process or if we've
// got too many processes. See also ShouldTryToUseExistingProcessHost in
// this file.
if (RenderProcessHost::run_renderer_in_process() ||
RenderProcessHostImpl::GetProcessCountForLimit() >=
RenderProcessHostImpl::GetMaxRendererProcessCount()) {
return;
}
// Don't create a spare renderer when the system is under load. This is
// currently approximated by only looking at the memory pressure. See also
// https://crbug.com/852905.
auto* memory_monitor = base::MemoryPressureMonitor::Get();
if (memory_monitor &&
memory_monitor->GetCurrentPressureLevel() >=
base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE) {
return;
}
process_startup_timer_ = std::make_unique<base::ElapsedTimer>();
RenderProcessHost* new_spare_rph =
RenderProcessHostImpl::CreateRenderProcessHost(
browser_context, nullptr /* site_instance */);
new_spare_rph->AddObserver(this);
new_spare_rph->Init();
spare_rphs_.push_back(new_spare_rph);
// Use the new timeout if there is no previous renderer or
// the specified timeout will be triggered after the current timeout
// (or not triggered at all).
if (!had_spare_renderer || !timeout.has_value() ||
DestroyTimerWillFireBefore(timeout.value())) {
deferred_destroy_timer_.Stop();
StartDestroyTimer(timeout);
}
// The spare render process isn't ready, so wait and do the "spare render
// process changed" callback in RenderProcessReady().
}
void SpareRenderProcessHostManagerImpl::DeferredWarmupSpare(
BrowserContext* browser_context,
base::TimeDelta delay,
std::optional<base::TimeDelta> timeout) {
delay_timer_ = std::make_unique<base::ElapsedTimer>();
deferred_warmup_timer_.Start(
FROM_HERE, delay,
base::BindOnce(
[](SpareRenderProcessHostManagerImpl* self,
base::WeakPtr<BrowserContext> browser_context,
std::optional<base::TimeDelta> timeout) {
// Don't create spare process if the browser context is destroyed
// or the shutdown has started.
if (browser_context && !browser_context->ShutdownStarted()) {
self->WarmupSpare(browser_context.get(), timeout);
}
},
base::Unretained(this), browser_context->GetWeakPtr(), timeout));
}
RenderProcessHost* SpareRenderProcessHostManagerImpl::MaybeTakeSpare(
BrowserContext* browser_context,
SiteInstanceImpl* site_instance) {
// Give embedder a chance to disable using a spare RenderProcessHost for
// certain SiteInstances. Some navigations, such as to NTP or extensions,
// require passing command-line flags to the renderer process at process
// launch time, but this cannot be done for spare RenderProcessHosts, which
// are started before it is known which navigation might use them. So, a
// spare RenderProcessHost should not be used in such cases.
//
// Note that exempting NTP and extensions from using the spare process might
// also happen via HasProcess check below (which returns true for
// process-per-site SiteInstances if the given process-per-site process
// already exists). Despite this potential overlap, it is important to do
// both kinds of checks (to account for other non-ntp/extension
// process-per-site scenarios + to work correctly even if
// ShouldUseSpareRenderProcessHost starts covering non-process-per-site
// scenarios).
std::optional<ContentBrowserClient::SpareProcessRefusedByEmbedderReason>
refuse_reason =
GetContentClient()->browser()->ShouldUseSpareRenderProcessHost(
browser_context, site_instance->GetSiteInfo().site_url());
bool embedder_allows_spare_usage = !refuse_reason.has_value();
// The spare RenderProcessHost always launches with JIT enabled, so if JIT
// is disabled for the site then it's not possible to use this as the JIT
// policy will differ.
if (GetContentClient()->browser()->IsJitDisabledForSite(
browser_context, site_instance->GetSiteInfo().process_lock_url())) {
embedder_allows_spare_usage = false;
refuse_reason =
ContentBrowserClient::SpareProcessRefusedByEmbedderReason::JitDisabled;
}
// V8 optimizations are globally enabled or disabled for a whole process, and
// spare renderers always have V8 optimizations enabled, so we can never use
// them if they're supposed to be disabled for this site.
if (GetContentClient()->browser()->AreV8OptimizationsDisabledForSite(
browser_context, site_instance->GetSiteInfo().process_lock_url())) {
embedder_allows_spare_usage = false;
refuse_reason = ContentBrowserClient::SpareProcessRefusedByEmbedderReason::
V8OptimizationsDisabled;
}
if (refuse_reason.has_value()) {
base::UmaHistogramEnumeration(
"BrowserRenderProcessHost.SpareProcessRefusedByEmbedderReason",
refuse_reason.value());
}
// Do not use spare renderer if running an experiment to run SkiaFontManager.
// SkiaFontManager needs to be initialized during renderer creation.
// This is temporary and will be removed after the experiment has concluded;
// see crbug.com/335680565.
bool use_skia_font_manager = false;
#if BUILDFLAG(IS_WIN)
use_skia_font_manager =
GetContentClient()->browser()->ShouldUseSkiaFontManager(
site_instance->GetSiteURL());
#endif
// We shouldn't use the spare if:
// 1. The SiteInstance has already got an associated process. This is
// important to avoid taking and then immediately discarding the spare
// for process-per-site scenarios (which the HasProcess call below
// accounts for). Note that HasProcess will return false and allow using
// the spare if the given process-per-site process hasn't been launched.
// 2. The SiteInstance has opted out of using the spare process.
bool site_instance_allows_spare_usage =
!site_instance->HasProcess() &&
site_instance->CanAssociateWithSpareProcess();
bool hosts_pdf_content = site_instance->GetSiteInfo().is_pdf();
// Get the StoragePartition for |site_instance|. Note that this might be
// different than the default StoragePartition for |browser_context|.
StoragePartition* site_storage =
browser_context->GetStoragePartition(site_instance);
// GetSpare UMA metrics.
using SpareProcessMaybeTakeAction =
RenderProcessHostImpl::SpareProcessMaybeTakeAction;
SpareProcessMaybeTakeAction action =
SpareProcessMaybeTakeAction::kNoSparePresent;
RenderProcessHost* next_spare_rph =
!spare_rphs_.empty() ? spare_rphs_[0] : nullptr;
if (!next_spare_rph) {
action = SpareProcessMaybeTakeAction::kNoSparePresent;
} else if (browser_context != next_spare_rph->GetBrowserContext()) {
action = SpareProcessMaybeTakeAction::kMismatchedBrowserContext;
} else if (!next_spare_rph->InSameStoragePartition(site_storage)) {
action = SpareProcessMaybeTakeAction::kMismatchedStoragePartition;
} else if (!embedder_allows_spare_usage) {
action = SpareProcessMaybeTakeAction::kRefusedByEmbedder;
} else if (!site_instance_allows_spare_usage) {
action = SpareProcessMaybeTakeAction::kRefusedBySiteInstance;
} else if (hosts_pdf_content) {
action = SpareProcessMaybeTakeAction::kRefusedForPdfContent;
} else {
action = SpareProcessMaybeTakeAction::kSpareTaken;
}
UMA_HISTOGRAM_ENUMERATION(
"BrowserRenderProcessHost.SpareProcessMaybeTakeAction", action);
// Decide whether to take or drop the spare process.
RenderProcessHost* returned_process = nullptr;
if (next_spare_rph &&
browser_context == next_spare_rph->GetBrowserContext() &&
next_spare_rph->InSameStoragePartition(site_storage) &&
!site_instance->IsGuest() && embedder_allows_spare_usage &&
site_instance_allows_spare_usage && !hosts_pdf_content &&
!use_skia_font_manager) {
CHECK(next_spare_rph->HostHasNotBeenUsed());
// If the spare process ends up getting killed, the spare manager should
// discard the spare RPH, so if one exists, it should always be live here.
CHECK(next_spare_rph->IsInitializedAndNotDead());
DCHECK_EQ(SpareProcessMaybeTakeAction::kSpareTaken, action);
returned_process = next_spare_rph;
ReleaseSpare(next_spare_rph);
} else if (!RenderProcessHostImpl::IsSpareProcessKeptAtAllTimes()) {
// If the spare shouldn't be kept around, then discard it as soon as we
// find that the current spare was mismatched.
CleanupSpares();
} else if (RenderProcessHostImpl::GetProcessCountForLimit() >=
RenderProcessHostImpl::GetMaxRendererProcessCount()) {
// Drop all spares if we are at a process limit and the spare wasn't taken.
// This helps avoid process reuse.
// TODO(pmonette): Only cleanup n spares, where n is the count of processes
// that is over the limit.
CleanupSpares();
}
return returned_process;
}
void SpareRenderProcessHostManagerImpl::PrepareForFutureRequests(
BrowserContext* browser_context,
std::optional<base::TimeDelta> delay) {
if (RenderProcessHostImpl::IsSpareProcessKeptAtAllTimes()) {
std::optional<base::TimeDelta> timeout = std::nullopt;
if (base::FeatureList::IsEnabled(
features::kAndroidWarmUpSpareRendererWithTimeout)) {
if (features::kAndroidSpareRendererCreationTiming.Get() !=
features::kAndroidSpareRendererCreationDelayedDuringLoading) {
// The creation of the spare renderer will be managed in
// WebContentsImpl::DidStopLoading or
// WebContentsImpl::OnFirstVisuallyNonEmptyPaint.
return;
}
if (features::kAndroidSpareRendererTimeoutSeconds.Get() > 0) {
timeout =
base::Seconds(features::kAndroidSpareRendererTimeoutSeconds.Get());
}
}
// Always keep around a spare process for the most recently requested
// |browser_context|.
if (delay.has_value()) {
DeferredWarmupSpare(browser_context, *delay, timeout);
} else {
WarmupSpare(browser_context, timeout);
}
} else {
// Discard the ignored (probably non-matching) spares so as not to waste
// resources.
CleanupSpares();
}
}
void SpareRenderProcessHostManagerImpl::CleanupSpares() {
std::vector<RenderProcessHost*> spare_rphs = std::move(spare_rphs_);
// Stop the destroy timer since it is no longer required.
deferred_destroy_timer_.Stop();
for (RenderProcessHost* spare_rph : spare_rphs) {
// Stop observing the process, to avoid getting notifications as a
// consequence of the Cleanup call below - such notification could call
// back into CleanupSpare leading to stack overflow.
spare_rph->RemoveObserver(this);
// Make sure the RenderProcessHost object gets destroyed.
if (!spare_rph->AreRefCountsDisabled()) {
spare_rph->Cleanup();
}
for (auto& observer : observer_list_) {
observer.OnSpareRenderProcessHostRemoved(spare_rph);
}
}
}
void SpareRenderProcessHostManagerImpl::SetDeferTimerTaskRunnerForTesting(
scoped_refptr<base::SequencedTaskRunner> task_runner) {
deferred_warmup_timer_.SetTaskRunner(task_runner);
deferred_destroy_timer_.SetTaskRunner(task_runner);
}
void SpareRenderProcessHostManagerImpl::ReleaseSpare(RenderProcessHost* host) {
// Erase while intentionally preserving the order of the other elements.
size_t removed = std::erase(spare_rphs_, host);
CHECK_EQ(removed, 1u);
host->RemoveObserver(this);
for (auto& observer : observer_list_) {
observer.OnSpareRenderProcessHostRemoved(host);
}
}
void SpareRenderProcessHostManagerImpl::RenderProcessReady(
RenderProcessHost* host) {
CHECK(base::Contains(spare_rphs_, host));
CHECK(process_startup_timer_);
UMA_HISTOGRAM_TIMES("BrowserRenderProcessHost.SpareProcessStartupTime",
process_startup_timer_->Elapsed());
process_startup_timer_.reset();
for (auto& observer : observer_list_) {
observer.OnSpareRenderProcessHostReady(host);
}
}
void SpareRenderProcessHostManagerImpl::RenderProcessExited(
RenderProcessHost* host,
const ChildProcessTerminationInfo& info) {
ReleaseSpare(host);
// Make sure the RenderProcessHost object gets destroyed.
if (!host->AreRefCountsDisabled()) {
host->Cleanup();
}
if (spare_rphs_.empty()) {
deferred_destroy_timer_.Stop();
}
}
void SpareRenderProcessHostManagerImpl::RenderProcessHostDestroyed(
RenderProcessHost* host) {
ReleaseSpare(host);
}
} // namespace content