I've seen an odd problem three times in the past two weeks. I suspect a Linux 3.6 regression. I"m on 3.6.3-1.fc17.x86_64. I run a parallel compilation, and no progress is made. All cpus are pegged at 100% system time by the respective cc1plus processes. Reading /proc/<pid>/stack shows either [<ffffffff8108e01a>] __cond_resched+0x2a/0x40 [<ffffffff8114e432>] isolate_migratepages_range+0xb2/0x620 [<ffffffff8114eba4>] compact_zone+0x144/0x410 [<ffffffff8114f152>] compact_zone_order+0x82/0xc0 [<ffffffff8114f271>] try_to_compact_pages+0xe1/0x130 [<ffffffff816143db>] __alloc_pages_direct_compact+0xaa/0x190 [<ffffffff81133d26>] __alloc_pages_nodemask+0x526/0x990 [<ffffffff81171496>] alloc_pages_vma+0xb6/0x190 [<ffffffff81182683>] do_huge_pmd_anonymous_page+0x143/0x340 [<ffffffff811549fd>] handle_mm_fault+0x27d/0x320 [<ffffffff81620adc>] do_page_fault+0x15c/0x4b0 [<ffffffff8161d625>] page_fault+0x25/0x30 [<ffffffffffffffff>] 0xffffffffffffffff or [<ffffffffffffffff>] 0xffffffffffffffff seemingly at random (i.e. if I read that file twice in a row, I might see different results). If I had to guess, I'd say that perf shows no 'faults'. The livelock resolved after several minutes (and before I got far enough with perf to get more useful results). Every time this happens, firefox hangs but everything else keeps working. If I trigger it again, I'll try to grab /proc/zoneinfo and /proc/meminfo. --Andy -- 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>