On Thu, Aug 18, 2011 at 4:18 AM, Pavel Ivanov <paivanof@xxxxxxxxx> wrote: >>> Why "killing" does not appear here? Why it try to "find some >>> recently used page"? >> >> Because killing is the last resort. As long as kernel can free >> a page by dropping an unmodified file-backed page, it will do that. >> When there is nothing more to drop, and still more free pages >> are needed, _then_ kernel will start oom killing. > > I have a little concern about this explanation of yours. Suppose we > have some amount of more or less actively executing processes in the > system. Suppose they started to use lots of resident memory. Amount of > memory they use is less than total available physical memory but when > we add total size of code for those processes it would be several > pages more than total size of physical memory. As I understood from > your explanation in such situation one process will execute its time > slice, kernel will switch to other one, find that its code was pushed > out of RAM, read it from disk, execute its time slice, switch to next > process, read its code from disk, execute and so on. So system will be > virtually unusable because of constantly reading from disk just to > execute next small piece of code. But oom will never be firing in such > situation. Is my understanding correct? Yes. > Shouldn't it be considered as an unwanted behavior? Yes. But all alternatives (such as killing some process) seem to be worse. -- vda -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>