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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "chrome/browser/chromeos/memory/oom_priority_manager.h" | |
6 | |
7 #include <algorithm> | |
8 #include <set> | |
9 #include <vector> | |
10 | |
11 #include "ash/multi_profile_uma.h" | |
12 #include "ash/session/session_state_delegate.h" | |
13 #include "ash/shell.h" | |
14 #include "base/bind.h" | |
15 #include "base/bind_helpers.h" | |
16 #include "base/command_line.h" | |
17 #include "base/memory/memory_pressure_monitor.h" | |
18 #include "base/metrics/field_trial.h" | |
19 #include "base/metrics/histogram.h" | |
20 #include "base/process/process.h" | |
21 #include "base/strings/string16.h" | |
22 #include "base/strings/string_number_conversions.h" | |
23 #include "base/strings/string_util.h" | |
24 #include "base/strings/utf_string_conversions.h" | |
25 #include "base/synchronization/lock.h" | |
26 #include "base/threading/thread.h" | |
27 #include "build/build_config.h" | |
28 #include "chrome/browser/browser_process.h" | |
29 #include "chrome/browser/browser_process_platform_part_chromeos.h" | |
30 #include "chrome/browser/chromeos/memory/low_memory_observer.h" | |
31 #include "chrome/browser/chromeos/memory/oom_memory_details.h" | |
32 #include "chrome/browser/chromeos/memory/system_memory_stats_recorder.h" | |
33 #include "chrome/browser/ui/browser.h" | |
34 #include "chrome/browser/ui/browser_iterator.h" | |
35 #include "chrome/browser/ui/browser_list.h" | |
36 #include "chrome/browser/ui/host_desktop.h" | |
37 #include "chrome/browser/ui/tab_contents/tab_contents_iterator.h" | |
38 #include "chrome/browser/ui/tabs/tab_strip_model.h" | |
39 #include "chrome/browser/ui/tabs/tab_utils.h" | |
40 #include "chrome/common/chrome_constants.h" | |
41 #include "chrome/common/url_constants.h" | |
42 #include "chromeos/chromeos_switches.h" | |
43 #include "content/public/browser/browser_thread.h" | |
44 #include "content/public/browser/notification_service.h" | |
45 #include "content/public/browser/notification_types.h" | |
46 #include "content/public/browser/render_process_host.h" | |
47 #include "content/public/browser/render_widget_host.h" | |
48 #include "content/public/browser/web_contents.h" | |
49 #include "content/public/browser/zygote_host_linux.h" | |
50 | |
51 using base::TimeDelta; | |
52 using base::TimeTicks; | |
53 using content::BrowserThread; | |
54 using content::WebContents; | |
55 | |
56 namespace chromeos { | |
57 | |
58 namespace { | |
59 | |
60 // The default interval in seconds after which to adjust the oom_score_adj | |
61 // value. | |
62 const int kAdjustmentIntervalSeconds = 10; | |
63 | |
64 // For each period of this length we record a statistic to indicate whether | |
65 // or not the user experienced a low memory event. If you change this interval | |
66 // you must replace Tabs.Discard.DiscardInLastMinute with a new statistic. | |
67 const int kRecentTabDiscardIntervalSeconds = 60; | |
68 | |
69 // If there has been no priority adjustment in this interval, we assume the | |
70 // machine was suspended and correct our timing statistics. | |
71 const int kSuspendThresholdSeconds = kAdjustmentIntervalSeconds * 4; | |
72 | |
73 // When switching to a new tab the tab's renderer's OOM score needs to be | |
74 // updated to reflect its front-most status and protect it from discard. | |
75 // However, doing this immediately might slow down tab switch time, so wait | |
76 // a little while before doing the adjustment. | |
77 const int kFocusedTabScoreAdjustIntervalMs = 500; | |
78 | |
79 // Returns a unique ID for a WebContents. Do not cast back to a pointer, as | |
80 // the WebContents could be deleted if the user closed the tab. | |
81 int64 IdFromWebContents(WebContents* web_contents) { | |
82 return reinterpret_cast<int64>(web_contents); | |
83 } | |
84 | |
85 } // namespace | |
86 | |
87 //////////////////////////////////////////////////////////////////////////////// | |
88 // OomPriorityManager | |
89 | |
90 OomPriorityManager::TabStats::TabStats() | |
91 : is_app(false), | |
92 is_reloadable_ui(false), | |
93 is_playing_audio(false), | |
94 is_pinned(false), | |
95 is_selected(false), | |
96 is_discarded(false), | |
97 renderer_handle(0), | |
98 tab_contents_id(0) { | |
99 } | |
100 | |
101 OomPriorityManager::TabStats::~TabStats() { | |
102 } | |
103 | |
104 OomPriorityManager::OomPriorityManager() | |
105 : focused_tab_process_info_(std::make_pair(0, 0)), | |
106 discard_count_(0), | |
107 recent_tab_discard_(false) { | |
108 // Use the old |LowMemoryObserver| when there is no |MemoryPressureMonitor|. | |
109 if (!base::MemoryPressureMonitor::Get()) | |
110 low_memory_observer_.reset(new LowMemoryObserver); | |
111 | |
112 registrar_.Add(this, | |
113 content::NOTIFICATION_RENDERER_PROCESS_CLOSED, | |
114 content::NotificationService::AllBrowserContextsAndSources()); | |
115 registrar_.Add(this, | |
116 content::NOTIFICATION_RENDERER_PROCESS_TERMINATED, | |
117 content::NotificationService::AllBrowserContextsAndSources()); | |
118 registrar_.Add(this, | |
119 content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED, | |
120 content::NotificationService::AllBrowserContextsAndSources()); | |
121 } | |
122 | |
123 OomPriorityManager::~OomPriorityManager() { | |
124 Stop(); | |
125 } | |
126 | |
127 void OomPriorityManager::Start() { | |
128 if (!timer_.IsRunning()) { | |
129 timer_.Start(FROM_HERE, | |
130 TimeDelta::FromSeconds(kAdjustmentIntervalSeconds), | |
131 this, | |
132 &OomPriorityManager::AdjustOomPriorities); | |
133 } | |
134 if (!recent_tab_discard_timer_.IsRunning()) { | |
135 recent_tab_discard_timer_.Start( | |
136 FROM_HERE, | |
137 TimeDelta::FromSeconds(kRecentTabDiscardIntervalSeconds), | |
138 this, | |
139 &OomPriorityManager::RecordRecentTabDiscard); | |
140 } | |
141 start_time_ = TimeTicks::Now(); | |
142 // If a |LowMemoryObserver| exists we use the old system, otherwise we create | |
143 // a |MemoryPressureListener| to listen for memory events. | |
144 if (low_memory_observer_) { | |
145 low_memory_observer_->Start(); | |
146 } else { | |
147 base::MemoryPressureMonitor* monitor = base::MemoryPressureMonitor::Get(); | |
148 if (monitor) { | |
149 memory_pressure_listener_.reset(new base::MemoryPressureListener( | |
150 base::Bind(&OomPriorityManager::OnMemoryPressure, | |
151 base::Unretained(this)))); | |
152 base::MemoryPressureListener::MemoryPressureLevel level = | |
153 monitor->GetCurrentPressureLevel(); | |
154 if (level == | |
155 base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) { | |
156 OnMemoryPressure(level); | |
157 } | |
158 } | |
159 } | |
160 } | |
161 | |
162 void OomPriorityManager::Stop() { | |
163 timer_.Stop(); | |
164 recent_tab_discard_timer_.Stop(); | |
165 if (low_memory_observer_) | |
166 low_memory_observer_->Stop(); | |
167 else | |
168 memory_pressure_listener_.reset(); | |
169 } | |
170 | |
171 std::vector<base::string16> OomPriorityManager::GetTabTitles() { | |
172 TabStatsList stats = GetTabStatsOnUIThread(); | |
173 base::AutoLock oom_score_autolock(oom_score_lock_); | |
174 std::vector<base::string16> titles; | |
175 titles.reserve(stats.size()); | |
176 TabStatsList::iterator it = stats.begin(); | |
177 for ( ; it != stats.end(); ++it) { | |
178 base::string16 str; | |
179 str.reserve(4096); | |
180 int score = oom_score_map_[it->child_process_host_id]; | |
181 str += base::IntToString16(score); | |
182 str += base::ASCIIToUTF16(" - "); | |
183 str += it->title; | |
184 str += base::ASCIIToUTF16(it->is_app ? " app" : ""); | |
185 str += base::ASCIIToUTF16(it->is_reloadable_ui ? " reloadable_ui" : ""); | |
186 str += base::ASCIIToUTF16(it->is_playing_audio ? " playing_audio" : ""); | |
187 str += base::ASCIIToUTF16(it->is_pinned ? " pinned" : ""); | |
188 str += base::ASCIIToUTF16(it->is_discarded ? " discarded" : ""); | |
189 titles.push_back(str); | |
190 } | |
191 return titles; | |
192 } | |
193 | |
194 // TODO(jamescook): This should consider tabs with references to other tabs, | |
195 // such as tabs created with JavaScript window.open(). We might want to | |
196 // discard the entire set together, or use that in the priority computation. | |
197 bool OomPriorityManager::DiscardTab() { | |
198 DCHECK_CURRENTLY_ON(BrowserThread::UI); | |
199 TabStatsList stats = GetTabStatsOnUIThread(); | |
200 if (stats.empty()) | |
201 return false; | |
202 // Loop until we find a non-discarded tab to kill. | |
203 for (TabStatsList::const_reverse_iterator stats_rit = stats.rbegin(); | |
204 stats_rit != stats.rend(); | |
205 ++stats_rit) { | |
206 int64 least_important_tab_id = stats_rit->tab_contents_id; | |
207 if (DiscardTabById(least_important_tab_id)) | |
208 return true; | |
209 } | |
210 return false; | |
211 } | |
212 | |
213 void OomPriorityManager::LogMemoryAndDiscardTab() { | |
214 LogMemory("Tab Discards Memory details", | |
215 base::Bind(&OomPriorityManager::PurgeMemoryAndDiscardTabs)); | |
216 } | |
217 | |
218 void OomPriorityManager::LogMemory(const std::string& title, | |
219 const base::Closure& callback) { | |
220 DCHECK_CURRENTLY_ON(BrowserThread::UI); | |
221 OomMemoryDetails::Log(title, callback); | |
222 } | |
223 | |
224 /////////////////////////////////////////////////////////////////////////////// | |
225 // OomPriorityManager, private: | |
226 | |
227 // static | |
228 void OomPriorityManager::PurgeMemoryAndDiscardTabs() { | |
229 if (g_browser_process && | |
230 g_browser_process->platform_part()->oom_priority_manager()) { | |
231 OomPriorityManager* manager = | |
232 g_browser_process->platform_part()->oom_priority_manager(); | |
233 manager->PurgeBrowserMemory(); | |
234 manager->DiscardTab(); | |
235 } | |
236 } | |
237 | |
238 // static | |
239 bool OomPriorityManager::IsReloadableUI(const GURL& url) { | |
240 // There are many chrome:// UI URLs, but only look for the ones that users | |
241 // are likely to have open. Most of the benefit is the from NTP URL. | |
242 const char* const kReloadableUrlPrefixes[] = { | |
243 chrome::kChromeUIDownloadsURL, | |
244 chrome::kChromeUIHistoryURL, | |
245 chrome::kChromeUINewTabURL, | |
246 chrome::kChromeUISettingsURL, | |
247 }; | |
248 // Prefix-match against the table above. Use strncmp to avoid allocating | |
249 // memory to convert the URL prefix constants into std::strings. | |
250 for (size_t i = 0; i < arraysize(kReloadableUrlPrefixes); ++i) { | |
251 if (!strncmp(url.spec().c_str(), | |
252 kReloadableUrlPrefixes[i], | |
253 strlen(kReloadableUrlPrefixes[i]))) | |
254 return true; | |
255 } | |
256 return false; | |
257 } | |
258 | |
259 bool OomPriorityManager::DiscardTabById(int64 target_web_contents_id) { | |
260 for (chrome::BrowserIterator it; !it.done(); it.Next()) { | |
261 Browser* browser = *it; | |
262 TabStripModel* model = browser->tab_strip_model(); | |
263 for (int idx = 0; idx < model->count(); idx++) { | |
264 // Can't discard tabs that are already discarded or active. | |
265 if (model->IsTabDiscarded(idx) || (model->active_index() == idx)) | |
266 continue; | |
267 WebContents* web_contents = model->GetWebContentsAt(idx); | |
268 int64 web_contents_id = IdFromWebContents(web_contents); | |
269 if (web_contents_id == target_web_contents_id) { | |
270 LOG(WARNING) << "Discarding tab " << idx | |
271 << " id " << target_web_contents_id; | |
272 // Record statistics before discarding because we want to capture the | |
273 // memory state that lead to the discard. | |
274 RecordDiscardStatistics(); | |
275 model->DiscardWebContentsAt(idx); | |
276 recent_tab_discard_ = true; | |
277 return true; | |
278 } | |
279 } | |
280 } | |
281 return false; | |
282 } | |
283 | |
284 void OomPriorityManager::RecordDiscardStatistics() { | |
285 // Record a raw count so we can compare to discard reloads. | |
286 discard_count_++; | |
287 UMA_HISTOGRAM_CUSTOM_COUNTS( | |
288 "Tabs.Discard.DiscardCount", discard_count_, 1, 1000, 50); | |
289 | |
290 // TODO(jamescook): Maybe incorporate extension count? | |
291 UMA_HISTOGRAM_CUSTOM_COUNTS( | |
292 "Tabs.Discard.TabCount", GetTabCount(), 1, 100, 50); | |
293 // Record the discarded tab in relation to the amount of simultaneously | |
294 // logged in users. | |
295 ash::MultiProfileUMA::RecordDiscardedTab( | |
296 ash::Shell::GetInstance()->session_state_delegate()-> | |
297 NumberOfLoggedInUsers()); | |
298 | |
299 // TODO(jamescook): If the time stats prove too noisy, then divide up users | |
300 // based on how heavily they use Chrome using tab count as a proxy. | |
301 // Bin into <= 1, <= 2, <= 4, <= 8, etc. | |
302 if (last_discard_time_.is_null()) { | |
303 // This is the first discard this session. | |
304 TimeDelta interval = TimeTicks::Now() - start_time_; | |
305 int interval_seconds = static_cast<int>(interval.InSeconds()); | |
306 // Record time in seconds over an interval of approximately 1 day. | |
307 UMA_HISTOGRAM_CUSTOM_COUNTS( | |
308 "Tabs.Discard.InitialTime2", interval_seconds, 1, 100000, 50); | |
309 } else { | |
310 // Not the first discard, so compute time since last discard. | |
311 TimeDelta interval = TimeTicks::Now() - last_discard_time_; | |
312 int interval_ms = static_cast<int>(interval.InMilliseconds()); | |
313 // Record time in milliseconds over an interval of approximately 1 day. | |
314 // Start at 100 ms to get extra resolution in the target 750 ms range. | |
315 UMA_HISTOGRAM_CUSTOM_COUNTS( | |
316 "Tabs.Discard.IntervalTime2", interval_ms, 100, 100000 * 1000, 50); | |
317 } | |
318 // Record chromeos's concept of system memory usage at the time of the | |
319 // discard. | |
320 RecordMemoryStats(RECORD_MEMORY_STATS_TAB_DISCARDED); | |
321 | |
322 // Set up to record the next interval. | |
323 last_discard_time_ = TimeTicks::Now(); | |
324 } | |
325 | |
326 void OomPriorityManager::RecordRecentTabDiscard() { | |
327 DCHECK_CURRENTLY_ON(BrowserThread::UI); | |
328 // If we change the interval we need to change the histogram name. | |
329 UMA_HISTOGRAM_BOOLEAN("Tabs.Discard.DiscardInLastMinute", | |
330 recent_tab_discard_); | |
331 // Reset for the next interval. | |
332 recent_tab_discard_ = false; | |
333 } | |
334 | |
335 void OomPriorityManager::PurgeBrowserMemory() { | |
336 // Based on experimental evidence, attempts to free memory from renderers | |
337 // have been too slow to use in OOM situations (V8 garbage collection) or | |
338 // do not lead to persistent decreased usage (image/bitmap caches). This | |
339 // function therefore only targets large blocks of memory in the browser. | |
340 // Note that other objects will listen to MemoryPressureListener events | |
341 // to release memory. | |
342 for (TabContentsIterator it; !it.done(); it.Next()) { | |
343 WebContents* web_contents = *it; | |
344 // Screenshots can consume ~5 MB per web contents for platforms that do | |
345 // touch back/forward. | |
346 web_contents->GetController().ClearAllScreenshots(); | |
347 } | |
348 } | |
349 | |
350 int OomPriorityManager::GetTabCount() const { | |
351 int tab_count = 0; | |
352 for (chrome::BrowserIterator it; !it.done(); it.Next()) | |
353 tab_count += it->tab_strip_model()->count(); | |
354 return tab_count; | |
355 } | |
356 | |
357 // Returns true if |first| is considered less desirable to be killed | |
358 // than |second|. | |
359 bool OomPriorityManager::CompareTabStats(TabStats first, | |
360 TabStats second) { | |
361 // Being currently selected is most important to protect. | |
362 if (first.is_selected != second.is_selected) | |
363 return first.is_selected; | |
364 | |
365 // Tab with internal web UI like NTP or Settings are good choices to discard, | |
366 // so protect non-Web UI and let the other conditionals finish the sort. | |
367 if (first.is_reloadable_ui != second.is_reloadable_ui) | |
368 return !first.is_reloadable_ui; | |
369 | |
370 // Being pinned is important to protect. | |
371 if (first.is_pinned != second.is_pinned) | |
372 return first.is_pinned; | |
373 | |
374 // Being an app is important too, as you're the only visible surface in the | |
375 // window and we don't want to discard that. | |
376 if (first.is_app != second.is_app) | |
377 return first.is_app; | |
378 | |
379 // Protect streaming audio and video conferencing tabs. | |
380 if (first.is_playing_audio != second.is_playing_audio) | |
381 return first.is_playing_audio; | |
382 | |
383 // TODO(jamescook): Incorporate sudden_termination_allowed into the sort | |
384 // order. We don't do this now because pages with unload handlers set | |
385 // sudden_termination_allowed false, and that covers too many common pages | |
386 // with ad networks and statistics scripts. Ideally we would like to check | |
387 // for beforeUnload handlers, which are likely to present a dialog asking | |
388 // if the user wants to discard state. crbug.com/123049 | |
389 | |
390 // Being more recently active is more important. | |
391 return first.last_active > second.last_active; | |
392 } | |
393 | |
394 void OomPriorityManager::AdjustFocusedTabScoreOnFileThread() { | |
395 DCHECK_CURRENTLY_ON(BrowserThread::FILE); | |
396 base::AutoLock oom_score_autolock(oom_score_lock_); | |
397 base::ProcessHandle pid = focused_tab_process_info_.second; | |
398 content::ZygoteHost::GetInstance()->AdjustRendererOOMScore( | |
399 pid, chrome::kLowestRendererOomScore); | |
400 oom_score_map_[focused_tab_process_info_.first] = | |
401 chrome::kLowestRendererOomScore; | |
402 } | |
403 | |
404 void OomPriorityManager::OnFocusTabScoreAdjustmentTimeout() { | |
405 BrowserThread::PostTask( | |
406 BrowserThread::FILE, FROM_HERE, | |
407 base::Bind(&OomPriorityManager::AdjustFocusedTabScoreOnFileThread, | |
408 base::Unretained(this))); | |
409 } | |
410 | |
411 void OomPriorityManager::Observe(int type, | |
412 const content::NotificationSource& source, | |
413 const content::NotificationDetails& details) { | |
414 base::AutoLock oom_score_autolock(oom_score_lock_); | |
415 switch (type) { | |
416 case content::NOTIFICATION_RENDERER_PROCESS_CLOSED: | |
417 case content::NOTIFICATION_RENDERER_PROCESS_TERMINATED: { | |
418 content::RenderProcessHost* host = | |
419 content::Source<content::RenderProcessHost>(source).ptr(); | |
420 oom_score_map_.erase(host->GetID()); | |
421 if (!low_memory_observer_) { | |
422 // Coming here we know that a renderer was just killed and memory should | |
423 // come back into the pool. However - the memory pressure observer did | |
424 // not yet update its status and therefore we ask it to redo the | |
425 // measurement, calling us again if we have to release more. | |
426 // Note: We do not only accelerate the discarding speed by doing another | |
427 // check in short succession - we also accelerate it because the timer | |
428 // driven MemoryPressureMonitor will continue to produce timed events | |
429 // on top. So the longer the cleanup phase takes, the more tabs will | |
430 // get discarded in parallel. | |
431 base::chromeos::MemoryPressureMonitor* monitor = | |
432 base::chromeos::MemoryPressureMonitor::Get(); | |
433 if (monitor) | |
434 monitor->ScheduleEarlyCheck(); | |
435 } | |
436 break; | |
437 } | |
438 case content::NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED: { | |
439 bool visible = *content::Details<bool>(details).ptr(); | |
440 if (visible) { | |
441 content::RenderProcessHost* render_host = | |
442 content::Source<content::RenderWidgetHost>(source).ptr()-> | |
443 GetProcess(); | |
444 focused_tab_process_info_ = std::make_pair(render_host->GetID(), | |
445 render_host->GetHandle()); | |
446 | |
447 // If the currently focused tab already has a lower score, do not | |
448 // set it. This can happen in case the newly focused tab is script | |
449 // connected to the previous tab. | |
450 ProcessScoreMap::iterator it; | |
451 it = oom_score_map_.find(focused_tab_process_info_.first); | |
452 if (it == oom_score_map_.end() | |
453 || it->second != chrome::kLowestRendererOomScore) { | |
454 // By starting a timer we guarantee that the tab is focused for | |
455 // certain amount of time. Secondly, it also does not add overhead | |
456 // to the tab switching time. | |
457 if (focus_tab_score_adjust_timer_.IsRunning()) | |
458 focus_tab_score_adjust_timer_.Reset(); | |
459 else | |
460 focus_tab_score_adjust_timer_.Start(FROM_HERE, | |
461 TimeDelta::FromMilliseconds(kFocusedTabScoreAdjustIntervalMs), | |
462 this, &OomPriorityManager::OnFocusTabScoreAdjustmentTimeout); | |
463 } | |
464 } | |
465 break; | |
466 } | |
467 default: | |
468 NOTREACHED() << L"Received unexpected notification"; | |
469 break; | |
470 } | |
471 } | |
472 | |
473 // Here we collect most of the information we need to sort the | |
474 // existing renderers in priority order, and hand out oom_score_adj | |
475 // scores based on that sort order. | |
476 // | |
477 // Things we need to collect on the browser thread (because | |
478 // TabStripModel isn't thread safe): | |
479 // 1) whether or not a tab is pinned | |
480 // 2) last time a tab was selected | |
481 // 3) is the tab currently selected | |
482 void OomPriorityManager::AdjustOomPriorities() { | |
483 if (BrowserList::GetInstance(chrome::HOST_DESKTOP_TYPE_ASH)->empty()) | |
484 return; | |
485 | |
486 // Check for a discontinuity in time caused by the machine being suspended. | |
487 if (!last_adjust_time_.is_null()) { | |
488 TimeDelta suspend_time = TimeTicks::Now() - last_adjust_time_; | |
489 if (suspend_time.InSeconds() > kSuspendThresholdSeconds) { | |
490 // We were probably suspended, move our event timers forward in time so | |
491 // when we subtract them out later we are counting "uptime". | |
492 start_time_ += suspend_time; | |
493 if (!last_discard_time_.is_null()) | |
494 last_discard_time_ += suspend_time; | |
495 } | |
496 } | |
497 last_adjust_time_ = TimeTicks::Now(); | |
498 | |
499 TabStatsList stats_list = GetTabStatsOnUIThread(); | |
500 BrowserThread::PostTask( | |
501 BrowserThread::FILE, FROM_HERE, | |
502 base::Bind(&OomPriorityManager::AdjustOomPrioritiesOnFileThread, | |
503 base::Unretained(this), stats_list)); | |
504 } | |
505 | |
506 OomPriorityManager::TabStatsList OomPriorityManager::GetTabStatsOnUIThread() { | |
507 DCHECK_CURRENTLY_ON(BrowserThread::UI); | |
508 TabStatsList stats_list; | |
509 stats_list.reserve(32); // 99% of users have < 30 tabs open | |
510 bool browser_active = true; | |
511 const BrowserList* ash_browser_list = | |
512 BrowserList::GetInstance(chrome::HOST_DESKTOP_TYPE_ASH); | |
513 for (BrowserList::const_reverse_iterator browser_iterator = | |
514 ash_browser_list->begin_last_active(); | |
515 browser_iterator != ash_browser_list->end_last_active(); | |
516 ++browser_iterator) { | |
517 Browser* browser = *browser_iterator; | |
518 bool is_browser_for_app = browser->is_app(); | |
519 const TabStripModel* model = browser->tab_strip_model(); | |
520 for (int i = 0; i < model->count(); i++) { | |
521 WebContents* contents = model->GetWebContentsAt(i); | |
522 if (!contents->IsCrashed()) { | |
523 TabStats stats; | |
524 stats.is_app = is_browser_for_app; | |
525 stats.is_reloadable_ui = | |
526 IsReloadableUI(contents->GetLastCommittedURL()); | |
527 stats.is_playing_audio = chrome::IsPlayingAudio(contents); | |
528 stats.is_pinned = model->IsTabPinned(i); | |
529 stats.is_selected = browser_active && model->IsTabSelected(i); | |
530 stats.is_discarded = model->IsTabDiscarded(i); | |
531 stats.last_active = contents->GetLastActiveTime(); | |
532 stats.renderer_handle = contents->GetRenderProcessHost()->GetHandle(); | |
533 stats.child_process_host_id = contents->GetRenderProcessHost()->GetID(); | |
534 stats.title = contents->GetTitle(); | |
535 stats.tab_contents_id = IdFromWebContents(contents); | |
536 stats_list.push_back(stats); | |
537 } | |
538 } | |
539 // We process the active browser window in the first iteration. | |
540 browser_active = false; | |
541 } | |
542 // Sort the data we collected so that least desirable to be | |
543 // killed is first, most desirable is last. | |
544 std::sort(stats_list.begin(), stats_list.end(), CompareTabStats); | |
545 return stats_list; | |
546 } | |
547 | |
548 // static | |
549 std::vector<OomPriorityManager::ProcessInfo> | |
550 OomPriorityManager::GetChildProcessInfos( | |
551 const TabStatsList& stats_list) { | |
552 std::vector<ProcessInfo> process_infos; | |
553 std::set<base::ProcessHandle> already_seen; | |
554 for (TabStatsList::const_iterator iterator = stats_list.begin(); | |
555 iterator != stats_list.end(); ++iterator) { | |
556 // stats_list contains entries for already-discarded tabs. If the PID | |
557 // (renderer_handle) is zero, we don't need to adjust the oom_score. | |
558 if (iterator->renderer_handle == 0) | |
559 continue; | |
560 | |
561 bool inserted = already_seen.insert(iterator->renderer_handle).second; | |
562 if (!inserted) { | |
563 // We've already seen this process handle. | |
564 continue; | |
565 } | |
566 | |
567 process_infos.push_back(std::make_pair( | |
568 iterator->child_process_host_id, iterator->renderer_handle)); | |
569 } | |
570 return process_infos; | |
571 } | |
572 | |
573 void OomPriorityManager::AdjustOomPrioritiesOnFileThread( | |
574 TabStatsList stats_list) { | |
575 DCHECK_CURRENTLY_ON(BrowserThread::FILE); | |
576 base::AutoLock oom_score_autolock(oom_score_lock_); | |
577 | |
578 // Remove any duplicate PIDs. Order of the list is maintained, so each | |
579 // renderer process will take on the oom_score_adj of the most important | |
580 // (least likely to be killed) tab. | |
581 std::vector<ProcessInfo> process_infos = GetChildProcessInfos(stats_list); | |
582 | |
583 // Now we assign priorities based on the sorted list. We're | |
584 // assigning priorities in the range of kLowestRendererOomScore to | |
585 // kHighestRendererOomScore (defined in chrome_constants.h). | |
586 // oom_score_adj takes values from -1000 to 1000. Negative values | |
587 // are reserved for system processes, and we want to give some room | |
588 // below the range we're using to allow for things that want to be | |
589 // above the renderers in priority, so the defined range gives us | |
590 // some variation in priority without taking up the whole range. In | |
591 // the end, however, it's a pretty arbitrary range to use. Higher | |
592 // values are more likely to be killed by the OOM killer. | |
593 float priority = chrome::kLowestRendererOomScore; | |
594 const int kPriorityRange = chrome::kHighestRendererOomScore - | |
595 chrome::kLowestRendererOomScore; | |
596 float priority_increment = | |
597 static_cast<float>(kPriorityRange) / process_infos.size(); | |
598 for (const auto& process_info : process_infos) { | |
599 int score = static_cast<int>(priority + 0.5f); | |
600 ProcessScoreMap::iterator it = | |
601 oom_score_map_.find(process_info.first); | |
602 // If a process has the same score as the newly calculated value, | |
603 // do not set it. | |
604 if (it == oom_score_map_.end() || it->second != score) { | |
605 content::ZygoteHost::GetInstance()->AdjustRendererOOMScore( | |
606 process_info.second, score); | |
607 oom_score_map_[process_info.first] = score; | |
608 } | |
609 priority += priority_increment; | |
610 } | |
611 } | |
612 | |
613 void OomPriorityManager::OnMemoryPressure( | |
614 base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) { | |
615 // For the moment we only do something when we reach a critical state. | |
616 if (memory_pressure_level == | |
617 base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) { | |
618 LogMemoryAndDiscardTab(); | |
619 } | |
620 // TODO(skuhne): If more memory pressure levels are introduced, we might | |
621 // consider to call PurgeBrowserMemory() before CRITICAL is reached. | |
622 } | |
623 | |
624 } // namespace chromeos | |
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