Dave Hansen wrote: > On Mon, 2007-03-12 at 19:16 +0300, Kirill Korotaev wrote: >> now VE2 maps the same page. You can't determine whether this page is mapped >> to this container or another one w/o page->container pointer. > > Hi Kirill, > > I thought we can always get from the page to the VMA. rmap provides > this to us via page->mapping and the 'struct address_space' or anon_vma. > Do we agree on that?
Not completely. When page is unmapped from the *very last* user its *first* toucher may already be dead. So we'll never find out who it was. > We can also get from the vma to the mm very easily, via vma->vm_mm, > right? > > We can also get from a task to the container quite easily. > > So, the only question becomes whether there is a 1:1 relationship > between mm_structs and containers. Does each mm_struct belong to one No. The question is "how to get a container that touched the page first" which is the same as "how to find mm_struct which touched the page first". Obviously there's no answer on this question unless we hold some direct page->container reference. This may be a hash, a direct on-page pointer, or mirrored array of pointers. > and only one container? Basically, can a threaded process have > different threads in different containers? > > It seems that we could bridge the gap pretty easily by either assigning > each mm_struct to a container directly, or putting some kind of > task-to-mm lookup. Perhaps just a list like > mm->tasks_using_this_mm_list. This could work for reclamation: we scan through all the mm_struct-s within the container and shrink its' pages, but we can't make LRU this way. > Not rocket science, right? > > -- Dave > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [EMAIL PROTECTED] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
