Date: Wed, 24 May 2017 01:00:51 -0700 From: Shrikanth Kamath <shrikanth07@gmail.com> To: freebsd-hackers@freebsd.org Subject: Difference between p_vmspace quota between stable/11 and stable/10 Message-ID: <CAEOAkMWuptktG0UmNUuePwm6UZKkghyLUQoJtqzF4=wGoCYXSA@mail.gmail.com>
next in thread | raw e-mail | index | archive | help
I have a certain application(32 bit user space running in compat mode
in 64 bit system X86) which does a fork, and the child process does a
series of mmap calls as part of a scaling test. I am currently
debugging an issue with this application which hits a ENOMEM when it
is run on a stable/11 based setup and fails subsequent mmap and/or any
malloc calls v/s stable/10 where the issue is not seen.. I probed the
vm_map_find function using DTrace when "execname" was my application
in question, and got these readings
fbt:kernel:vm_map_find:entry
/self->trace == 1/ /*enabled only during sys_mmap call of this application */
{
@bytes[args[4]] = sum(args[4]);
printf("request length [%x]", args[4]);
}
For stable_10 --> Total of 124 requests (length requested was
0x500000) with the test successful
124 * 0x500000 (5MB) ~ 620MB
For stable_11 --> Total of 109 mmap requests
(0x500000/0x200000/0x3ff000 are the different vm_size_t length
arguments in vm_map_find). The test fails after 386MB has been
approved.
24 * 0x500000 (5MB) ~ 120MB
82 * 0x200000 (2MB) ~ 164MB
3 * 0x3ff000 (4MB) ~ 12MB
The process parent rlimits are
# cat /proc/5058/rlimit
cpu -1 -1
fsize -1 -1
data 3221225472 3221225472
stack 16777216 16777216
core -1 -1
rss 67108864 33265819648
memlock 67108864 33265819648
nproc 512 512
nofile 1024 1024
sbsize -1 -1
vmem -1 -1
npts -1 -1
swap -1 -1
kqueues -1 -1
umtx -1 -1
The requests started failing in stable/11 with just 386 MB approved
v/s stable/10 which was successful in approving ~620MB.
My stable/11 is from early days and is at GRN 302410 (probably 10 months old)
Any pointers or tips on what to probe further will be very helpful. Is
there any limits breach that I should probe further? The limits set
when a process is forked?
Should I probe the p->vmspace initiazliation?
Thanks,
--
Shrikanth R K
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAEOAkMWuptktG0UmNUuePwm6UZKkghyLUQoJtqzF4=wGoCYXSA>