linux-kernel - Re: [PATCH] [13/16] HWPOISON: The high level memory error handler in the VM v3

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Message-ID: <20090602140545.GP1065@one.firstfloor.org>
Date:	Tue, 2 Jun 2009 16:05:45 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Nick Piggin <npiggin@...e.de>
Cc:	Andi Kleen <andi@...stfloor.org>, hugh@...itas.com,
	riel@...hat.com, akpm@...ux-foundation.org, chris.mason@...cle.com,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	fengguang.wu@...el.com
Subject: Re: [PATCH] [13/16] HWPOISON: The high level memory error handler in the VM v3

> I was kind of thinking about we could SIGKILL them as they try
> to access it or fsync it. But then the question is how long to
> keep SIGKILLing? At one end of the scale you could do stupid
> and simple and have another error flag in the mapping to do
> the SIGKILL just once for the next read/write/fsync etc. Or

It's pretty radical to SIGKILL on a IO error.

Perhaps we can make fsync give EIO again in this case 
with a new mapping flag. The question would be when
to clear that flag again. Probably devil in the details.

> at the other end, you keep the page in the pagecache and
> poisoned, and kill everyone until the page is explicitly truncated
> by userspace. I don't really know...

We do that for the swapcache to avoid a similar problem, but
it's more a hack than a good solution.  I think it would be
worse for the page cache, because if you stop the program
then there's no reason to keep that around.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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