Messages in this thread | | | Date | Fri, 12 Apr 2013 22:43:51 +0900 | From | Mitsuhiro Tanino <> | Subject | Re: [RFC Patch 0/2] mm: Add parameters to make kernel behavior at memory error on dirty cache selectable |
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(2013/04/11 22:00), Ric Mason wrote: > Hi Mitsuhiro, > On 04/11/2013 08:51 PM, Mitsuhiro Tanino wrote: >> (2013/04/11 12:53), Simon Jeons wrote: >>> One question against mce instead of the patchset. ;-) >>> >>> When check memory is bad? Before memory access? Is there a process scan it period? >> Hi Simon-san, >> >> Yes, there is a process to scan memory periodically. >> >> At Intel Nehalem-EX and CPUs after Nehalem-EX generation, MCA recovery >> is supported. MCA recovery provides error detection and isolation >> features to work together with OS. >> One of the MCA Recovery features is Memory Scrubbing. It periodically >> checks memory in the background of OS. > > Memory Scrubbing is a kernel thread? Where is the codes of memory scrubbing?
Hi Ric,
No. One of the MCA Recovery features is Memory Scrubbing. And Memory Scrubbing is a hardware feature of Intel CPU.
OS has a hwpoison feature which is included at mm/memory-failure.c. A main function is memory_failure().
If Memory Scrubbing finds a memory error, MCA recovery notifies SRAO error into OS and OS handles the SRAO error using hwpoison function.
>> If Memory Scrubbing find an uncorrectable error on a memory before >> OS accesses the memory bit, MCA recovery notifies SRAO error into OS > > It maybe can't find memory error timely since it is sleeping when memory error occur, can this case happened?
Memory Scrubbing seems to be operated periodically but I don't have information about how oftern it is executed.
Regards, Mitsuhiro Tanino
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