Messages in this thread | | | Date | Wed, 10 Jun 2009 17:20:11 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH] [13/16] HWPOISON: The high level memory error handler in the VM v5 |
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On Wed, Jun 10, 2009 at 04:59:39PM +0800, Nick Piggin wrote: > On Wed, Jun 10, 2009 at 04:38:03PM +0800, Wu Fengguang wrote: > > On Wed, Jun 10, 2009 at 12:05:53AM +0800, Hugh Dickins wrote: > > > I think a much more sensible approach would be to follow the page > > > migration technique of replacing the page's ptes by a special swap-like > > > entry, then do the killing from do_swap_page() if a process actually > > > tries to access the page. > > > > We call that "late kill" and will be enabled when > > sysctl_memory_failure_early_kill=0. Its default value is 1. > > What's the use of this? What are the tradeoffs, in what situations > should an admin set this sysctl one way or the other?
Good questions.
My understanding is, when an application is generating data A, B, C in sequence, and A is found to be corrupted by the kernel. Does it make sense for the application to continue generate B and C? Or, are there data dependencies between them? With late kill, it becomes more likely that the disk contain new versions of B/C and old version of A, so will more likely create data inconsistency.
So early kill is more safe.
Thanks, Fengguang
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