Hi SwaJime, you need to run 'sudo su' first and then the free sequence. Echoing the value to drop_caches requiere super user permissions. HTH
2017-11-15 19:38 GMT+01:00 SwaJime <159...@bugs.launchpad.net>: > yas, when I try that, I get "bash: /proc/sys/vm/drop_caches: Permission > denied" on Ubuntu 16.04 > > -- > You received this bug notification because you are subscribed to the bug > report. > https://bugs.launchpad.net/bugs/159356 > > Title: > System freeze on high memory usage > > Status in linux package in Ubuntu: > Incomplete > > Bug description: > I run a batch matlab job server here at my lab, running Dapper 6.06 (for > the LTS). One of the users has submitted a very memory-consuming job, which > successfully crashes the server. Upon closer inspection, the crash happens > like this: > 1. I run matlab with the given file (as an ordinary, unpriveleged user) > 2. RAM usage quickly fills up > 3. Once the RAM meter hits 100%, the system freezes: All SSH connections > freeze up, and while switching VTs directly on the machine works, no new > processes run - so one can't log in, or do anything if he is logged in. > (Sometimes typing doesn't work at all) > > Note that the swap - while 7 gigs of it are available - is never used. > (The machine has 7 gigs of RAM as well) > > I've tried the same on my Gutsy 32-bit box, and there was no system > freezeup - matlab simply notified that the system was out of memory. > However, it did this once memory was 100% in use - and still, swap > didn't get used at all! (Though it is mounted correctly and shows up > in "top" and "free"). > > So first thing's first - I'd like to eliminate the crash issue. I > suppose I could switch the server to 32-bit, but I think that would be > a performance loss, considering that it does a lot of heavy > computation. There is no reason, however, that this should happen on a > 64-bit machine anyway. Why does it? > > WORKAROUND: Enabling DMA in the BIOS > > To manage notifications about this bug go to: > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/159356/+subscriptions > -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/159356 Title: System freeze on high memory usage Status in linux package in Ubuntu: Incomplete Bug description: I run a batch matlab job server here at my lab, running Dapper 6.06 (for the LTS). One of the users has submitted a very memory-consuming job, which successfully crashes the server. Upon closer inspection, the crash happens like this: 1. I run matlab with the given file (as an ordinary, unpriveleged user) 2. RAM usage quickly fills up 3. Once the RAM meter hits 100%, the system freezes: All SSH connections freeze up, and while switching VTs directly on the machine works, no new processes run - so one can't log in, or do anything if he is logged in. (Sometimes typing doesn't work at all) Note that the swap - while 7 gigs of it are available - is never used. (The machine has 7 gigs of RAM as well) I've tried the same on my Gutsy 32-bit box, and there was no system freezeup - matlab simply notified that the system was out of memory. However, it did this once memory was 100% in use - and still, swap didn't get used at all! (Though it is mounted correctly and shows up in "top" and "free"). So first thing's first - I'd like to eliminate the crash issue. I suppose I could switch the server to 32-bit, but I think that would be a performance loss, considering that it does a lot of heavy computation. There is no reason, however, that this should happen on a 64-bit machine anyway. Why does it? WORKAROUND: Enabling DMA in the BIOS To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/159356/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
