Messages in this thread | | | Date | Thu, 28 May 2009 14:15:41 +0200 | From | Nick Piggin <> | Subject | Re: [PATCH] [13/16] HWPOISON: The high level memory error handler in the VM v3 |
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On Thu, May 28, 2009 at 12:51:03PM +0200, Andi Kleen wrote: > On Thu, May 28, 2009 at 06:33:00PM +0800, Wu Fengguang wrote: > > > > > You haven't waited on writeback here AFAIKS, and have you > > > > > *really* verified it is safe to call delete_from_swap_cache? > > > > > > > > Good catch. I'll soon submit patches for handling the under > > > > read/write IO pages. In this patchset they are simply ignored. > > > > > > Yes, we assume the IO device does something sensible with the poisoned > > > cache lines and aborts. Later we can likely abort IO requests in a early > > > stage on the Linux, but that's more advanced. > > > > > > The question is if we need to wait on writeback for correctness? > > > > Not necessary. Because I'm going to add a me_writeback() handler. > > Ok but without it. Let's assume me_writeback() is in the future.
For correctness for what? You can't remove a page from swapcache or pagecache under writeback because then the mm thinks that location is not being used.
> I'm mainly interested in correctness (as in not crashing) of this > version now. > > Also writeback seems to be only used by nfs/afs/nilfs2, not in > the normal case, unless I'm misreading the code.
I don't follow. What writeback are you talking about?
> > The nilfs2 case seems weird, I haven't completely read that. > > > Then the writeback pages simply won't reach here. And it won't > > magically go into writeback state, since the page has been locked. > > But since we take the page lock they should not be in writeback anyways, > no?
No. PG_writeback was introduced so as to reduce page lock hold times (most of writeback runs without page lock held).
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