On Thu, 11 Feb 2010 01:14:43 -0800 (PST) David Rientjes <rientjes@xxxxxxxxxx> wrote: > On Wed, 10 Feb 2010, Rik van Riel wrote: > > > > OOM_ADJUST_MIN and OOM_ADJUST_MAX have been exported to userspace since > > > 2006 via include/linux/oom.h. This alters their values from -16 to -1000 > > > and from +15 to +1000, respectively. > > > > That seems like a bad idea. Google may have the luxury of > > being able to recompile all its in-house applications, but > > this will not be true for many other users of /proc/<pid>/oom_adj > > > > Changing any value that may have a tendency to be hardcoded elsewhere is > always controversial, but I think the nature of /proc/pid/oom_adj allows > us to do so for two specific reasons: > > - hardcoded values tend not the fall within a range, they tend to either > always prefer a certain task for oom kill first or disable oom killing > entirely. The current implementation uses this as a bitshift on a > seemingly unpredictable and unscientific heuristic that is very > difficult to predict at runtime. This means that fewer and fewer > applications would hardcode a value of '8', for example, because its > semantics depends entirely on RAM capacity of the system to begin with > since badness() scores are only useful when used in comparison with > other tasks. You'd be amazed what dumb things applications do. Get thee to http://google.com/codesearch?hl=en&lr=&q=[^a-z]oom_adj[^a-z]&sbtn=Search and start reading. All 641 matches ;) Here's one which which writes -16: http://google.com/codesearch/p?hl=en#eN5TNOm7KtI/trunk/wlan/vendor/asus/eeepc/init.rc&q=[^a-z]oom_adj[^a-z]&sa=N&cd=70&ct=rc Let's not change the ABI please. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>