On Wed, Sep 23, 2015 at 4:47 AM, Prem Kumar <[email protected]> wrote:
> also wondering if there is a way I can list Active memory map showing me > what is cached? > > -regards. > > On Tue, Sep 22, 2015 at 3:08 PM, Prem Kumar <[email protected]> > wrote: > >> Dear All, >> >> I have done quite a bit of reading on Active memory reported in >> /proc/meminfo and in short says it is never reclaimed unless absolutely >> necessary, and it caches the recently used files/pages in memory. Although >> I fail to understand the consequences that I face here. >> >> I have disk-less and swap-less nodes. So all I have to do, is play with >> the RAM on the box. Issue that brought me here is investigating why after >> running some applications, used memory is never available for use with any >> other applications. >> >> In other words I cannot run any programs that requests memory more than >> what is shown as free in the output of free command and MemFree in the >> output of the cat /proc/meminfo >> For example if I ran any program that requires more than 6GB on the first >> node below and more than 1GB on the second node below they fail instantly, >> and work fine if within the limist of free. There is nothing else running >> on the system other than system processes/services. >> >> total used free shared buffers cached >> Mem: 23 17 6 0 0 9 >> -/+ buffers/cache: 8 15 >> Swap: 0 0 0 >> >> total used free shared buffers cached >> Mem: 23 22 1 0 0 0 >> -/+ buffers/cache: 21 1 >> Swap: 0 0 0 >> >> Since the applications that ran previously are not running any more "even >> though they died out of memory because they requested more memory than >> available", shouldn't the OS see that any memory used previously as useless >> and can it not reclaim that for use with the next job/program on that >> machine. >> >> On every machine that I have run into this problem the out put of >> /proc/meminfo shows that Active memory is used up the amount shown in the >> free command and limits my further runs. >> >> This is driving me insane and making me feel stupid knowing that OS is >> smart enough to handle this, then what am I missing here to understand? >> Please advise. >> >> Appreciate any insight into this. >> >> Best Regards, >> Prem >> >> >> > > > Dear Prem welcome to kernelnewbies :) First of all, please don't do top posting when replying. Follow like what I and the rest of list member do. Btw, looking from the free output, I have a doubt about your statement that your first application took 6 GB and secondly it took 1 GB. Assuming your application doesn't thing like memory locking in kernel space, i guess it takes 20+ GB of RAM. So, before we go further, could you re run your applications and use ps or top to see both the VSIZE and RSS they take ? Regarding memory claiming, yes after app is killed (using any ways possible: ctrl-c, sending kill/term/quit signal, OOM etc), any memory allocated by this task are freed. It happen on both active and inactive pages -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
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