On 27 Únor 2012, 11:26, Peter Kjellström wrote: > On Sunday 26 February 2012 19.59.07 Tomas Vondra wrote: > ... >> i.e. about 200 MB of free memory, but apache fails because of segfaults >> when forking a child process: >> >> [16:49:51 2012] [error] (12)Cannot allocate memory: fork: Unable to >> fork new process >> [16:51:17 2012] [notice] child pid 2577 exit signal Segmentation >> fault (11) > > In general things can get quite bad with relatively high memory pressure > and > no swap. Sure, but there's no such pressure. There was almost 200MB of "free" memory (used for page cache, not dirty thus easy to drop). > That said, one thing that comes to mind is stacksize. When forking the > linux > kernel needs whatever the current stacksize is to be available as (free + > free > swap). > > Also, just because you see Y bytes free doesn't mean you can successfully > malloc that much (fragmentation, memory zones, etc.). Yup, I'm aware of that. But it's rather improbable, especially given the other symptoms. Update: After submitting the original post, I've noticed that these issues probably started about a week ago after upgrading a kernel and several related packages. I've had a swap there and the issues were not as severe, so I haven't noticed that before. I do remember I got an OOM error during that upgrade and I thought I've dealt with it properly, but maybe not. So I've reinstalled (remove+install) all those packages, rebooted and the problems disappeared. I will check that in the evening, but hopefully it's fixed. kind regards