Messages in this thread | | | Date | Mon, 05 Oct 2009 15:23:29 +0900 | From | Hidetoshi Seto <> | Subject | Re: [BUGFIX -v7] x86, MCE: Fix bugs and issues of MCE log ring buffer |
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Hi Huang,
Huang Ying wrote: > Current MCE log ring buffer has following bugs and issues: > > - On larger systems the 32 size buffer easily overflow, losing events. > > - We had some reports of events getting corrupted which were also > blamed on the ring buffer. > > - There's a known livelock, now hit by more people, under high error > rate. > > We fix these bugs and issues via making MCE log ring buffer as > lock-less per-CPU ring buffer.
Now I have a real problem on the small MCE log buffer on my new large system with Nehalem which has many cpus/banks in one socket... So I'd like to solve the problem asap. I think this problem might block some distros to support new processor.
Last week I reviewed your patch again and noticed that it is doing a lot of changes at once. I suppose that this method must be one of reasons why your patch seems to be so hard to review, and why it is taking long time to be accepted by x86 maintainers.
Fortunately I had some spare time so I carefully broke your patch into some purpose-designed pieces. It would be the most significant change that now there are 2 steps to convert the buffer structure - 1) to make it per-CPU and 2) to make it ring buffer.
Also I fixed some problem in your patch, found on the way to make this patch set. I'll explain about my changes later using diff from your change. Comments are welcomed.
Thanks, H.Seto
Hidetoshi Seto (10): x86, mce: remove tsc handling from mce_read x86, mce: mce_read can check args without mutex x86, mce: change writer timeout in mce_read x86, mce: use do-while in mce_log x86, mce: make mce_log buffer to per-CPU, prep x86, mce: make mce_log buffer to per-CPU x86, mce: remove for-loop in mce_log x86, mce: change barriers in mce_log x86, mce: make mce_log buffer to ring buffer x86, mce: move mce_log_init() into mce_cap_init()
arch/x86/include/asm/mce.h | 43 ++++-- arch/x86/kernel/cpu/mcheck/mce.c | 299 +++++++++++++++++++++++--------------- 2 files changed, 211 insertions(+), 131 deletions(-)
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