commit e923f7c4a3d117cb7fb45c775a9dd5912de6e81c
author cdumez@apple.com <cdumez@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> Sat Jun 23 00:09:37 2018 +0000
committer cdumez@apple.com <cdumez@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc> Sat Jun 23 00:09:37 2018 +0000
tree 7ebb92ed677d462c2a8c7ac679fd0a4d387cb339
parent 31fc3561a2b3e8c44b1ca123c418618b23a9d817

Implement IPC throttling to keep the main thread responsive when a process misbehaves
https://bugs.webkit.org/show_bug.cgi?id=186607
<rdar://problem/41073205>

Reviewed by Geoff Garen and Brady Eidson.

Implement IPC throttling to keep the main thread responsive when a process misbehaves.
Instead of doing one main runloop dispatch per incoming message, we now do a single
runloop dispatch and process incoming messages in batch. We put a limit on the number
of messages to be processed in a batch (600). If the queue is larger that this limit,
we'll schedule a 0-timer to process remaining messages, giving the main runloop a chance
to process other events. Additionally, if an IPC connection keeps hitting this maximum
batch size limit, we implement back off and we'll further decrease the number of messages
we process in each batch (going as low as 60). This keeps Safari responsive enough to
allow the user to close the bad tab (even on older devices such as iPhone 5s).

Finally, if the incoming message queue becomes too large (50000), we go one step further
and kill the IPC connection in order to maintain performance / battery life.

Every time we apply throttling or terminate a connection due to throttling, we do a
RELEASE_LOG_ERROR() with useful information in order to help diagnose potential issues
in the future.

For now, incoming IPC messages throttling is only enabled on the UIProcess' connections
to the WebProcesses.

* Platform/IPC/Connection.cpp:
(IPC::Connection::Connection):
(IPC::Connection::enqueueIncomingMessage):
(IPC::Connection::MessagesThrottler::MessagesThrottler):
(IPC::Connection::MessagesThrottler::scheduleMessagesDispatch):
(IPC::Connection::MessagesThrottler::numberOfMessagesToProcess):
(IPC::Connection::dispatchIncomingMessages):
* Platform/IPC/Connection.h:
* Platform/IPC/mac/ConnectionMac.mm:
(IPC::Connection::kill):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@233111 268f45cc-cd09-0410-ab3c-d52691b4dbfc