I talked about my summarization tool in the previous post. I have pushed the source code in github https://github.com/kalyanceg/summarize . Its completely undocumented. Probably I will add a javadoc for all methods and classes in a couple of weeks. If somebody wishes to contribute to the codebase or build over the existing utility, feel free to checkout the repository and it will be good if you push the changes (productive ones) back to the repo.
Started debugging an issue where Linux started calling OOM reaper despite tons of memory is used as Linux cached pages. My assumption was if there is a memory pressure, cache should shrink and leave way for the application to use. This is the documented and expected behavior. OOM reaper is called when few number of times page allocation has failed consequently. If for example mysql wants to grow its buffer and it asks for a page allocation and if the page allocation fails repeatedly, kernel invokes oom reaper. OOM reaper won't move out pages, it sleeps for some time and sees if kswapd or a program has freed up caches/application pages. If not it will start doing the dirty job of killing applications and freeing up memory. In our mysql setup, mysql is the application using most of the Used Memory, so no other application can free up memory for mysql to use. Cached pages are stored as 2 lists in Linux kernel viz active and inactive.
More details here
https://www.kernel.org/doc/gorman…
More details here
https://www.kernel.org/doc/gorman…
Comments
Post a Comment