Customer feedback! Begin forwarded message: Date: Fri, 2 Sep 2011 20:30:52 GMT From: bugzilla-daemon@xxxxxxxxxxxxxxxxxxx To: akpm@xxxxxxxxxxxxxxxxxxxx Subject: [Bug 41822] New: the swap is used too often and its content doesn't get reloaded automatically https://bugzilla.kernel.org/show_bug.cgi?id=41822 Summary: the swap is used too often and its content doesn't get reloaded automatically Product: Memory Management Version: 2.5 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Other AssignedTo: akpm@xxxxxxxxxxxxxxxxxxxx ReportedBy: unggnu@xxxxxxxxxxxxxx Regression: No I have 4 GB of Ram and used to disable the Swap since some time on my systems but one of my hosts is also used as a build client which sometimes results in memory bottlenecks. That's why I have activated a Swap of 5 GB. The reason why I used to disable the Swap is because even though that there is enough memory parts of it get swapped which results in sluggish applications. Imho this is wrong. And even on other systems with normal Desktop usage and 4GB Ram things get swapped. The swap should only be used if not enough memory is available or might be in the nearby future. If there is enough memory available later on the Swap content should be loaded into memory again even without being needed right now. But this doesn't happen so the applications get sluggish over time although less than 2 GB memory is actual used. To prevent this issue I run `swapoff -a && swapon -a` every morning since at least ~500 MB is swapped after a night of building while only ~1.2 GB of actual memory is used. Of course there is the memory Cache but since the Swap is most of the time pretty slow it is kind of counterproductive to swap memory (which is actually needed by applications) for caching files which might not be needed again. So please change the behavior or make it configurable to only use the Swap if not enough memory is left and to reload the content again if there is enough memory available afterwards. And please don't swap memory content to have more available for caching or whatever reason it is used on systems with enough available memory. The file cache should always have lower priority then the application memory. I am using Kernel 2.6.38 but this issue happens since a long time. --- Comment #1 from unggnu@xxxxxxxxxxxxxx 2011-09-02 20:30:49 --- For example the output of free this morning: Fri Sep 2 09:20:27 CEST 2011 total used free shared buffers cached Mem: 3980388 2047368 1933020 0 180372 1286792 -/+ buffers/cache: 580204 3400184 Swap: 5758972 749744 5009228 -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>