Can be application warmed before lowmemorykiller kills it?

answered 2016-05-10 09:03:16 +0300

spiiroin
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While process specific warnings about oom killer activity are not available, MCE daemon is tracking (absolute) system memory pressure via the memnotify kernel interface. Device specific configuration is used to map that in to 3 logical levels ("normal", "warning", "critical" - or "unknown" in case memnotify support / configuration is not present). On warning level non-essential resources should be released, and on critical level oom killing of some processes can be expected.

These logical levels are exposed on D-Bus system bus. The interface is introspectable and can thus be used for example via nemo-qml-plugin-dbus / inspected via qdbus utility:

% /usr/lib/qt5/bin/qdbus --system com.nokia.mce /com/nokia/mce/request|grep memo
method QString com.nokia.mce.request.get_memory_level()
%  /usr/lib/qt5/bin/qdbus --system com.nokia.mce /com/nokia/mce/signal|grep memo
signal void com.nokia.mce.signal.sig_memory_level_ind(QString memory_level)

As an example, the current state can be queried from command line via:

% dbus-send --system --type=method_call --print-reply --dest=com.nokia.mce /com/nokia/mce/request com.nokia.mce.request.get_memory_level

And tracked via:

% dbus-monitor --system sender=com.nokia.mce,interface=com.nokia.mce.signal,member=sig_memory_level_ind