| === tafa2- is now known as tafa2 | ||
| === zzz is now known as xxx | ||
| === xxx is now known as xxxzzz | ||
| === xxxzzz is now known as xxxyzzz | ||
| m15k | Hi guys. Should ufw dhcp-pd work out of the box? | 13:01 |
|---|---|---|
| Sircle | https://pastebin.mozilla.org/9078945 | 13:06 |
| Sircle | Is there anything wrong with this syntax. I am trying to allow one ip and block all but its blocking all ips (including the one I whitelisted) https://pastebin.mozilla.org/9078945 | 13:06 |
| zul | coreycb: ping neutron-vpnaas could use a rebuild in the cloud-archive https://pastebin.com/hL9b25q7 | 14:43 |
| jamespage | zul: neutron-vpn-agent has gone | 15:06 |
| jamespage | as in the vpn bits run as an extension to the neutron-l3-agent in queens | 15:10 |
| zul | argh...ok | 15:27 |
| sdeziel | I have a bunch of QEMU VMs with small RAM allocations (256M or less) but the VM's kernel seems to be missing ~20M leading to only ~236M visible/usable. Any way to find where the rest is gone? | 21:41 |
| sdeziel | "journalctl -kocat | grep Memory" gives me: Memory: 227764K/261624K available (8530K kernel code, 1309K rwdata, 3992K rodata, 1508K init, 1316K bss, 33860K reserved, 0K cma-reserved) | 21:42 |
| sdeziel | 261624K is pretty close to what the VM is given 262144K | 21:43 |
| nacc | sdeziel: says 33M reserved? | 21:43 |
| sdeziel | nacc: yeah, any way to influence this? Or learn what it's for? | 21:44 |
| sdeziel | is that a safety stash to be used only when under memory pressure? | 21:44 |
| nacc | sdeziel: can you `cat /proc/meminfo` to a pastebin? | 21:44 |
| sdeziel | https://paste.ubuntu.com/p/7mPvT9hf96/ | 21:45 |
| nacc | lol which give sa different number :) | 21:45 |
| sdeziel | my 236M visible from "free -m" is exactly the MemTotal | 21:45 |
| nacc | sdeziel: you've got about 20 M of reclaimable slab memory | 21:46 |
| sdeziel | I know that long ago there was a thing like reserved memory for DMA/ISA | 21:46 |
| nacc | which is relatively high for a small footprint system | 21:46 |
| sdeziel | SReclaimable > | 21:46 |
| nacc | sdeziel: yeah | 21:47 |
| nacc | i believe you can force that to reclaim by drop_caches | 21:47 |
| * sdeziel wonders how to reclaim | 21:47 | |
| nacc | sdeziel: try echo 3 > /proc/sys/vm/drop_caches | 21:48 |
| sdeziel | brought it down to ~8M | 21:48 |
| sdeziel | the that is poking at something that's not MemTotal AFAICT | 21:48 |
| nacc | sdeziel: err, duh, you're right | 21:48 |
| nacc | sdeziel: can you pastebin the full dmesg? | 21:49 |
| sdeziel | I experimented with an even smaller VM (192M assigned) and was also missing 20M | 21:49 |
| sdeziel | https://paste.ubuntu.com/p/8ysM3kGX4t/ | 21:50 |
| nacc | sdeziel: i used to know this really well, but i'm a few years rusty now :/ | 21:52 |
| nacc | sdeziel: trying to remember | 21:52 |
| sdeziel | nacc: hehe, nothing urgent, I'm only trying to reclaim as much as I can to keep my super old VM server from running out of RAM | 21:54 |
| nacc | sdeziel: iirc, that memory is kernel pages | 21:54 |
| nacc | sdeziel: and i think that means you used something like 20M of bootmem or so | 21:55 |
| nacc | whcih can't be freed normally | 21:55 |
| sdeziel | I wonder what that means: e820: update [mem 0x00000000-0x00000fff] usable ==> reserved | 21:55 |
| sdeziel | hmm, bootmem you say | 21:55 |
| nacc | sdeziel: that's my recollection, the kernel's bootsrap memory | 21:56 |
| nacc | sdeziel: that's referring to the e820 map in firmware | 21:56 |
| nacc | your bios tells the kerenl physically what addresses are allowed, etc | 21:56 |
| sdeziel | OK | 21:57 |
| TJ- | sdeziel: the kernel protects the first 64KB of memory from use, and actively scans it for corruption (to detect writes to the NULL page | 21:57 |
| sdeziel | TJ-: vm.mmap_min_addr right ? | 21:57 |
| sdeziel | TJ-: I tried shrinking it from 65536 -> 2048 and didn't get anything back | 21:58 |
| sdeziel | I also booted the linux-image-kvm flavor and got much less RAM taken away from me | 21:58 |
| TJ- | sdeziel: I don't think so, no, the e820 0-0xFFF is reserving the first 4096 byte page for safety | 21:59 |
| sdeziel | the problem with the kvm flavor is that it's a wildly different beast | 21:59 |
| nacc | TJ-: oh you're right, i didn't read which message that was properly | 22:01 |
| sdeziel | TJ-: OK but if it's for safety purposes, shouldn't the kernel see it (and count it in MemTotal)? | 22:02 |
| sdeziel | "dmesg | grep BIOS-e820" shows 5 ranges as reserved | 22:05 |
| nacc | sdeziel: right those are bios reserved, and then the kernel removes a bit more | 22:06 |
| TJ- | sdeziel: no, because those reserved areas are often 'ROM' - e.g. system BIOS and option ROMs, or PCI device mappings | 22:06 |
| sdeziel | hmm | 22:08 |
| TJ- | sdeziel: see e.g. "sudo less /proc/iomem" | 22:08 |
| sdeziel | "000c0000-000c0dff : Video ROM" => the VM only has a serial console | 22:10 |
| TJ- | sdeziel: but the VM seabios presumably has a default e820 reservation for a standard VGA framebuffer | 22:11 |
| sdeziel | TJ-: I don't know that area at all but I would think that such mapping wouldn't remove RAM visible for the kernel | 22:14 |
| TJ- | In the dmesg Memory line you referenced, the 'reserved' is: (physpages - totalram_pages - totalcma_pages) << (PAGE_SHIFT - 10), | 22:19 |
| sdeziel | not sure where totalram_pages comes from though | 22:24 |
| sdeziel | I'm just lacking too much basic knowledge I guess I should start reading https://www.kernel.org/doc/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt | 22:26 |
| sdeziel | huh, this ^ not related at all | 22:28 |
| TJ- | no, that's about device-tree bindings | 22:31 |
| sdeziel | TJ-: yeah, I noticed. While I look around for documentation of the e820 memory mapping hints, do you know how I could minimize the amount of reserved memory? | 22:33 |
| sdeziel | TJ-: something to tweak with QEMU/seabios? | 22:33 |
| TJ- | sdeziel: did you pastebin the entire dmesg ? | 22:34 |
| sdeziel | TJ-: https://paste.ubuntu.com/p/8ysM3kGX4t/ | 22:35 |
| TJ- | sdeziel: and what's in /proc/iomem | 22:36 |
| sdeziel | qemu as invoked by libvirt: https://paste.ubuntu.com/p/FX8RtzN5wK/ | 22:36 |
| sdeziel | TJ-: iomem: https://paste.ubuntu.com/p/NV45Nk9bjm/ | 22:37 |
| hehehe | hehe | 23:02 |
| hehehe | any new exciting news? | 23:02 |
| dpb1 | yes | 23:03 |
| hehehe | cool | 23:04 |
| sdeziel | TJ-: nacc: thanks for the useful information | 23:52 |
| nacc | sdeziel: yw, hopefully you were able to figure stuff out? | 23:53 |
| sdeziel | nacc: not yet but I have some pointers now at least | 23:53 |
Generated by irclog2html.py 2.7 by Marius Gedminas - find it at mg.pov.lt!