Messages in this thread | | | Date | Thu, 10 Mar 2011 13:15:29 -0500 | From | Vivek Goyal <> | Subject | Re: [RFC] [PATCH 0/6] Provide cgroup isolation for buffered writes. |
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On Thu, Mar 10, 2011 at 10:08:03AM -0800, Justin TerAvest wrote:
[..] > > I don't like to increase size of page_cgroup but I think you can record > > information without increasing size of page_cgroup. > > > > A) As Andrea did, encode it to pc->flags. > > But I'm afraid that there is a racy case because memory cgroup uses some > > test_and_set() bits. > > B) I wonder why the information cannot be recorded in page->private. > > When page has buffers, you can record the information to buffer struct. > > About swapio (if you take care of), you can record information to bio. > > Hi Kame, > > I'm concerned that by using something like buffer_heads stored in > page->private, we will only be supported on some filesystems and not > others. In addition, I'm not sure if all filesystems attach buffer > heads at the same time; if page->private is modified in the flusher > thread, we might not be able to determine the thread that dirtied the > page in the first place.
I think the person who dirtied the page can store the information in page->private (assuming buffer heads were not generated) and if flusher thread later ends up generating buffer heads and ends up modifying page->private, this can be copied in buffer heads?
Thanks Vivek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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