(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface). This is ... interesting. On Thu, 12 Nov 2015 18:46:35 +0000 bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=107771 > > Bug ID: 107771 > Summary: Single process tries to use more than 1/2 physical > RAM, OS starts thrashing > Product: Memory Management > Version: 2.5 > Kernel Version: 4.3.0-040300-generic (Ubuntu) > Hardware: All > OS: Linux > Tree: Mainline > Status: NEW > Severity: normal > Priority: P1 > Component: Page Allocator > Assignee: akpm@xxxxxxxxxxxxxxxxxxxx > Reporter: theosib@xxxxxxxxx > Regression: No > > I have a 24-core (48 thread) system with 64GB of RAM. > > When I run multiple processes, I can use all of physical RAM before swapping > starts. However, if I'm running only a *single* process, the system will start > swapping after I've exceeded only 1/2 of available physical RAM. Only after > swap fills does it start using more of the physical RAM. > > I can't find any ulimit settings or anything else that would cause this to > happen intentionally. > > I had originally filed this against Ubuntu, but I'm now running a more recent > kernel, and the problem persists, so I think it's more appropriate to file > here. There are some logs that they had me collect, so if you want to see > them, the are here: > > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1513673 > > I don't recall this problem happening with older kernels (whatever came with > Ubuntu 15.04), although I may just not have noticed. By swapping early, I'm > limited by the speed of my SSD, which is moving only about 20MB/sec in each > direction, and that makes what I'm running take 10 times as long to complete. > > -- > 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>