Messages in this thread | | | Date | Thu, 19 Jan 2006 20:53:13 +0100 | From | Nick Piggin <> | Subject | Re: [patch 5/6] mm: simplify vmscan vs release refcounting |
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On Thu, Jan 19, 2006 at 11:35:29AM -0800, Linus Torvalds wrote: > > > On Thu, 19 Jan 2006, Nick Piggin wrote: > > > > The VM has an interesting race where a page refcount can drop to zero, but > > it is still on the LRU lists for a short time. This was solved by testing > > a 0->1 refcount transition when picking up pages from the LRU, and dropping > > the refcount in that case. > > Heh. Now you keep the count offset, but you also end up removing all the > comments about it (still) being -1 for free. > > And your changelog talks about "atomic_inc_not_zero()" even though the > code actually does > > atomic_add_unless(&page->_count, 1, -1); > > which makes it pretty confusing ;) > > I also think it's wrong - you've changed put_page_testzero() to use > "atomic_dec_and_test()", even though the count is based on -1. > > So this patch _only_ works together with the next one, and is invalid in > many ways on its own. You should re-split the de-skew part correctly.. >
Man I'm really happy one of us is awake. Sorry, I'll resend the last two.
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