On 8 Nov 2013 00:41, "Ben West" <b...@gowasabi.net> wrote: > > As someone who runs AA r38247 patched to include zram support, I can add anecdotal experience that some processes don't behave well when paged to swap. I'm running AR7240 devices with 32MB RAM (i.e. UBNT M gear) as mesh nodes, and I've found that services like olsrd, coovachilli, and wpa_supplicant seem to behave erratically if they're swapped out and then back in. For this reason, I only enable 3MBytes of swap, preferring not to depend on it for normal operation. Only enough so that a node can detect when it's in a low-memory state and do something to recover (e.g. reboot).
Have you tried turning down swappiness? The default setting likes to swap things out quicker then you would think. > > I've not had opportunity to test whether this problem also happens with the newer kernel under BB. > > > On Thu, Nov 7, 2013 at 4:10 PM, Hauke Mehrtens <ha...@hauke-m.de> wrote: >> >> On 11/07/2013 12:08 AM, Fernando Frediani wrote: >> > Hi Hauke, >> > >> > What you mean by zram worked differently ? As far as I know zram >> > (previously known as compcache) has been merged to the Linux Kernel at >> > 3.2 so it should be there on 3.3 as well (check drivers/staging/zram). >> >> In Kernel 3.3 zram depends on XVMALLOC being build into the kernel, but >> in OpenWrt our plan was to build zram completely in a module so if >> someone does not want it nothing changes. >> >> > I have talked to Bastien in another conversation and he mentioned he has >> > a WRT54G running fine with Barrier Breaker (which has zram as a kmod >> > package), but not sure it's enabled by default or not. I'm interested to >> > to hear if it's having any improvements (how effective the swap zram is >> > being used) and if it is a stripped down build (no LuCI and other >> > packages) or a normal build. Also how big the swap zram should be ? 6MB >> > (as kalua script suggests) or 8MB (half of the memory) ? >> >> Yes Bastien made the patch which introduced zram support. If you want >> that in AA, it should be possible to make it also build as a kernel >> module. When it is there you can try out what is the best size. >> >> > I have seen a couple of people saying they have managed to flash >> > brcm47xx Attitude Adjustment to WRT54G routers but got instability >> > issues (slowness or disconnects). >> >> Yes flashing works, it just runs out of memory very often and the OOM >> killer starts to kill processes. >> >> > So if Barrier Breaker is working fine on WRT54G (with zram activated?) >> > then what would be the challenges to port that work already done back to >> > Attitude Adjustment ? >> >> I do not know if it works fine on these devices, but if it does with >> some traffic going over the router over some time then we should try to >> backport zram support. >> >> > >> > Best regards, >> > >> > Fernando >> > >> > >> > On 6 November 2013 18:17, Hauke Mehrtens <ha...@hauke-m.de >> > <mailto:ha...@hauke-m.de>> wrote: >> > >> > On 11/06/2013 05:15 PM, Fernando Frediani wrote: >> > > Hello Hauke, >> > > >> > > I have seen a few emails from you on openwrt-devel list about the >> > zram module and also saw it is already present on the trunk(Barrier >> > Breaker). >> > > >> > > Was wondering if there is any work going on or will be to backport >> > it to Attitude Adjustment then perhaps we can run it on the good and >> > old WRT54G and similar models with 16MB ? How difficult is it to >> > backport to AA as it is already done for trunk ? >> > > >> > > >> > > Thanks and best regards, >> > > >> > > Fernando >> > > >> > Hi Fernando, >> > >> > I have no plan to backport zram to Attitude Adjustment. Attitude >> > Adjustment uses kernel 3.3 and there zram worked differently or was not >> > included at all, I do not know exactly. But I would like to see zram >> > backported to AA and would like to see a nice patch. >> > >> > Hauke >> > >> > >> _______________________________________________ >> openwrt-devel mailing list >> openwrt-devel@lists.openwrt.org >> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel > > > > > -- > Ben West > http://gowasabi.net > b...@gowasabi.net > 314-246-9434 > > _______________________________________________ > openwrt-devel mailing list > openwrt-devel@lists.openwrt.org > https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel >
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