Merge "logd: simplify Clear() + Prune() logic" (7a372d16) · Commits · e / os / android_system_core

logd/ChattyLogBuffer.cpp

+4 −9

Original line number	Diff line number	Diff line
		@@ -327,7 +327,6 @@ class LogBufferElementLast {
		//
		bool ChattyLogBuffer::Prune(log_id_t id, unsigned long pruneRows, uid_t caller_uid) {
		LogReaderThread* oldest = nullptr;
		bool busy = false;
		bool clearAll = pruneRows == ULONG_MAX;

		auto reader_threads_lock = std::lock_guard{reader_list()->reader_threads_lock()};
		@@ -359,17 +358,16 @@ bool ChattyLogBuffer::Prune(log_id_t id, unsigned long pruneRows, uid_t caller_u
		}

		if (oldest && oldest->start() <= element.sequence()) {
		busy = true;
		KickReader(oldest, id, pruneRows);
		break;
		return false;
		}

		it = Erase(it);
		if (--pruneRows == 0) {
		break;
		return true;
		}
		}
		return busy;
		return true;
		}

		// prune by worst offenders; by blacklist, UID, and by PID of system UID
		@@ -440,7 +438,6 @@ bool ChattyLogBuffer::Prune(log_id_t id, unsigned long pruneRows, uid_t caller_u
		LogBufferElement& element = *it;

		if (oldest && oldest->start() <= element.sequence()) {
		busy = true;
		// Do not let chatty eliding trigger any reader mitigation
		break;
		}
		@@ -577,7 +574,6 @@ bool ChattyLogBuffer::Prune(log_id_t id, unsigned long pruneRows, uid_t caller_u
		}

		if (oldest && oldest->start() <= element.sequence()) {
		busy = true;
		if (!whitelist) KickReader(oldest, id, pruneRows);
		break;
		}
		@@ -605,7 +601,6 @@ bool ChattyLogBuffer::Prune(log_id_t id, unsigned long pruneRows, uid_t caller_u
		}

		if (oldest && oldest->start() <= element.sequence()) {
		busy = true;
		KickReader(oldest, id, pruneRows);
		break;
		}
		@@ -615,5 +610,5 @@ bool ChattyLogBuffer::Prune(log_id_t id, unsigned long pruneRows, uid_t caller_u
		}
		}

		return (pruneRows > 0) && busy;
		return pruneRows == 0 \|\| it == logs().end();
		}

logd/CommandListener.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -82,7 +82,7 @@ int CommandListener::ClearCmd::runCommand(SocketClient* cli, int argc,
		return 0;
		}

		cli->sendMsg(buf()->Clear((log_id_t)id, uid) ? "busy" : "success");
		cli->sendMsg(buf()->Clear((log_id_t)id, uid) ? "success" : "busy");
		return 0;
		}

logd/SimpleLogBuffer.cpp

+29 −37

Original line number	Diff line number	Diff line
		@@ -212,24 +212,26 @@ bool SimpleLogBuffer::FlushTo(
		return true;
		}

		// clear all rows of type "id" from the buffer.
		bool SimpleLogBuffer::Clear(log_id_t id, uid_t uid) {
		bool busy = true;
		// If it takes more than 4 tries (seconds) to clear, then kill reader(s)
		for (int retry = 4;;) {
		if (retry == 1) { // last pass
		// Check if it is still busy after the sleep, we say prune
		// one entry, not another clear run, so we are looking for
		// the quick side effect of the return value to tell us if
		// we have a _blocked_ reader.
		// Try three times to clear, then disconnect the readers and try one final time.
		for (int retry = 0; retry < 3; ++retry) {
		{
		auto lock = std::lock_guard{lock_};
		busy = Prune(id, 1, uid);
		if (Prune(id, ULONG_MAX, uid)) {
		return true;
		}
		}
		sleep(1);
		}
		// Check if it is still busy after the sleep, we try to prune one entry, not another clear run,
		// so we are looking for the quick side effect of the return value to tell us if we have a
		// _blocked_ reader.
		bool busy = false;
		{
		auto lock = std::lock_guard{lock_};
		busy = !Prune(id, 1, uid);
		}
		// It is still busy, blocked reader(s), lets kill them all!
		// otherwise, lets be a good citizen and preserve the slow
		// readers and let the clear run (below) deal with determining
		// if we are still blocked and return an error code to caller.
		// It is still busy, disconnect all readers.
		if (busy) {
		auto reader_threads_lock = std::lock_guard{reader_list_->reader_threads_lock()};
		for (const auto& reader_thread : reader_list_->reader_threads()) {
		@@ -240,18 +242,8 @@ bool SimpleLogBuffer::Clear(log_id_t id, uid_t uid) {
		}
		}
		}
		}
		{
		auto lock = std::lock_guard{lock_};
		busy = Prune(id, ULONG_MAX, uid);
		}

		if (!busy \|\| !--retry) {
		break;
		}
		sleep(1); // Let reader(s) catch up after notification
		}
		return busy;
		return Prune(id, ULONG_MAX, uid);
		}

		// get the total space allocated to "id"
		@@ -313,16 +305,16 @@ bool SimpleLogBuffer::Prune(log_id_t id, unsigned long prune_rows, uid_t caller_

		if (oldest && oldest->start() <= element.sequence()) {
		KickReader(oldest, id, prune_rows);
		return true;
		return false;
		}

		stats_->Subtract(element.ToLogStatisticsElement());
		it = Erase(it);
		if (--prune_rows == 0) {
		return false;
		return true;
		}
		}
		return false;
		return true;
		}

		std::list<LogBufferElement>::iterator SimpleLogBuffer::Erase(