Hi :) On Wed, Sep 28, 2011 at 00:14, Prateek Sharma <prateek3.14@gmail.com> wrote:
Hello everyone, I am trying to understand the kernel page frame reclaiming mechanism, but one thing's bothering me: How does the kernel 'know' which anonymous pages to evict? In the LRU scheme, 'referenced/used' information for each page is required (AFAIK). But anonymous pages can be used by user processes 'at any time' without the kernel knowing about it.
Same question hog my mind too so far :) The only satisfying self answer I could deduce is: kernel can't track every access to pages when you do it like e.g mov %ax,8(%esp). What kernel could track is when you access data via wrappers. I forgot which ones, but remember some of them are updating those "referenced" etc flags. Perhaps something like get_pages or alike. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com