Messages in this thread | | | From | "Zhijian Li (Fujitsu)" <> | Subject | Re: [RFC PATCH v2 0/3] pmem memmap dump support | Date | Mon, 8 May 2023 09:45:57 +0000 |
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Dan,
On 29/04/2023 02:59, Dan Williams wrote: > Li Zhijian wrote: >> Hello folks, >> >> About 2 months ago, we posted our first RFC[3] and received your kindly feedback. Thank you :) >> Now, I'm back with the code. >> >> Currently, this RFC has already implemented to supported case D*. And the case A&B is disabled >> deliberately in makedumpfile. It includes changes in 3 source code as below: > > I think the reason this patchkit is difficult to follow is that it > spends a lot of time describing a chosen solution, but not enough time > describing the problem and the tradeoffs. > > For example why is updating /proc/vmcore with pmem metadata the chosen > solution? Why not leave the kernel out of it and have makedumpfile > tooling aware of how to parse persistent memory namespace info-blocks > and retrieve that dump itself? This is what I proposed here: > > http://lore.kernel.org/r/641484f7ef780_a52e2940@dwillia2-mobl3.amr.corp.intel.com.notmuch
Sorry for the late reply. I'm just back from the vacation. And sorry again for missing your previous *important* information in V1.
Your proposal also sounds to me with less kernel changes, but more ndctl coupling with makedumpfile tools. In my current understanding, it will includes following source changes.
-----------+-------------------------------------------------------------------+ Source | changes | -----------+-------------------------------------------------------------------+ I. | 1. enter force_raw in kdump kernel automatically(avoid metadata being updated again)| kernel | | | 2. mark the whole pmem's PT_LOAD for kexec_file_load(2) syscall | -----------+-------------------------------------------------------------------+ II. kexec- | 1. mark the whole pmem's PT_LOAD for kexe_load(2) syscall | tool | | -----------+-------------------------------------------------------------------+ III. | 1. parse the infoblock and calculate the boundaries of userdata and metadata | makedump- | 2. skip pmem userdata region | file | 3. exclude pmem metadata region if needed | -----------+-------------------------------------------------------------------+
I will try rewrite it with your proposal ASAP
Thanks again
Thanks Zhijian
> > ...but never got an answer, or I missed the answer. | |