| Message ID | 20191223152349.180172-1-chenzhou10@huawei.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | support reserving crashkernel above 4G on arm64 kdump | expand |
Hi all, Friendly ping... On 2019/12/23 23:23, Chen Zhou wrote: > This patch series enable reserving crashkernel above 4G in arm64. > > There are following issues in arm64 kdump: > 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail > when there is no enough low memory. > 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G, > in this case, if swiotlb or DMA buffers are required, crash dump kernel > will boot failure because there is no low memory available for allocation. > > To solve these issues, introduce crashkernel=X,low to reserve specified > size low memory. > Crashkernel=X tries to reserve memory for the crash dump kernel under > 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified > size low memory for crash kdump kernel devices firstly and then reserve > memory above 4G. > > When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low > is specified simultaneously, kernel should reserve specified size low memory > for crash dump kernel devices. So there may be two crash kernel regions, one > is below 4G, the other is above 4G. > In order to distinct from the high region and make no effect to the use of > kexec-tools, rename the low region as "Crash kernel (low)", and add DT property > "linux,low-memory-range" to crash dump kernel's dtb to pass the low region. > > Besides, we need to modify kexec-tools: > arm64: kdump: add another DT property to crash dump kernel's dtb(see [1]) > > The previous changes and discussions can be retrieved from: > > Changes since [v6] > - Fix build errors reported by kbuild test robot. > > Changes since [v5] > - Move reserve_crashkernel_low() into kernel/crash_core.c. > - Delete crashkernel=X,high. > - Modify crashkernel=X,low. > If crashkernel=X,low is specified simultaneously, reserve spcified size low > memory for crash kdump kernel devices firstly and then reserve memory above 4G. > In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then > pass to crash dump kernel by DT property "linux,low-memory-range". > - Update Documentation/admin-guide/kdump/kdump.rst. > > Changes since [v4] > - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike. > > Changes since [v3] > - Add memblock_cap_memory_ranges back for multiple ranges. > - Fix some compiling warnings. > > Changes since [v2] > - Split patch "arm64: kdump: support reserving crashkernel above 4G" as > two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate > patch. > > Changes since [v1]: > - Move common reserve_crashkernel_low() code into kernel/kexec_core.c. > - Remove memblock_cap_memory_ranges() i added in v1 and implement that > in fdt_enforce_memory_region(). > There are at most two crash kernel regions, for two crash kernel regions > case, we cap the memory range [min(regs[*].start), max(regs[*].end)] > and then remove the memory range in the middle. > > [1]: http://lists.infradead.org/pipermail/kexec/2019-August/023569.html > [v1]: https://lkml.org/lkml/2019/4/2/1174 > [v2]: https://lkml.org/lkml/2019/4/9/86 > [v3]: https://lkml.org/lkml/2019/4/9/306 > [v4]: https://lkml.org/lkml/2019/4/15/273 > [v5]: https://lkml.org/lkml/2019/5/6/1360 > [v6]: https://lkml.org/lkml/2019/8/30/142 > > Chen Zhou (4): > x86: kdump: move reserve_crashkernel_low() into crash_core.c > arm64: kdump: reserve crashkenel above 4G for crash dump kernel > arm64: kdump: add memory for devices by DT property, low-memory-range > kdump: update Documentation about crashkernel on arm64 > > Documentation/admin-guide/kdump/kdump.rst | 13 +++- > Documentation/admin-guide/kernel-parameters.txt | 12 +++- > arch/arm64/kernel/setup.c | 8 ++- > arch/arm64/mm/init.c | 61 ++++++++++++++++- > arch/x86/kernel/setup.c | 62 ++---------------- > include/linux/crash_core.h | 3 + > include/linux/kexec.h | 2 - > kernel/crash_core.c | 87 +++++++++++++++++++++++++ > kernel/kexec_core.c | 17 ----- > 9 files changed, 183 insertions(+), 82 deletions(-) >
On Thu, Mar 26, 2020 at 4:10 AM Chen Zhou <chenzhou10@huawei.com> wrote: > > Hi all, > > Friendly ping... I was asked about this patch series, and see that you last posted it in December. I think you should rebase it to linux-5.7-rc6 and post the entire series again to make progress, as it's unlikely that any maintainer would pick up the patches from last year. For the contents, everything seems reasonable to me, but I noticed that you are adding a property to the /chosen node without adding the corresponding documentation to Documentation/devicetree/bindings/chosen.txt Please add that, and Cc the devicetree maintainers on the updated patch. Arnd > On 2019/12/23 23:23, Chen Zhou wrote: > > This patch series enable reserving crashkernel above 4G in arm64. > > > > There are following issues in arm64 kdump: > > 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail > > when there is no enough low memory. > > 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G, > > in this case, if swiotlb or DMA buffers are required, crash dump kernel > > will boot failure because there is no low memory available for allocation. > > > > The previous changes and discussions can be retrieved from: > > > > Changes since [v6] > > - Fix build errors reported by kbuild test robot. ...
> On May 19, 2020, at 5:21 AM, Arnd Bergmann <arnd@arndb.de> wrote: > > On Thu, Mar 26, 2020 at 4:10 AM Chen Zhou <chenzhou10@huawei.com> wrote: >> >> Hi all, >> >> Friendly ping... > > I was asked about this patch series, and see that you last posted it in > December. I think you should rebase it to linux-5.7-rc6 and post the > entire series again to make progress, as it's unlikely that any maintainer > would pick up the patches from last year. > > For the contents, everything seems reasonable to me, but I noticed that > you are adding a property to the /chosen node without adding the > corresponding documentation to > Documentation/devicetree/bindings/chosen.txt > > Please add that, and Cc the devicetree maintainers on the updated > patch. > > Arnd > >> On 2019/12/23 23:23, Chen Zhou wrote: >>> This patch series enable reserving crashkernel above 4G in arm64. >>> >>> There are following issues in arm64 kdump: >>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail >>> when there is no enough low memory. >>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G, >>> in this case, if swiotlb or DMA buffers are required, crash dump kernel >>> will boot failure because there is no low memory available for allocation. >>> >>> The previous changes and discussions can be retrieved from: >>> >>> Changes since [v6] >>> - Fix build errors reported by kbuild test robot. > ... Hi We found https://lkml.org/lkml/2020/4/30/1583 Has cured our Out-Of-Memory kdump failures. From Henry Willard Subject [PATCH] mm: Limit boost_watermark on small zones. I am currently not on linux-kernel@vger.kernel.org. dlist for all to see this message so you may want to rebase and see if this cures your OoM issue and share the results.
Hi Arnd, On 2020/5/19 18:21, Arnd Bergmann wrote: > On Thu, Mar 26, 2020 at 4:10 AM Chen Zhou <chenzhou10@huawei.com> wrote: >> Hi all, >> >> Friendly ping... > I was asked about this patch series, and see that you last posted it in > December. I think you should rebase it to linux-5.7-rc6 and post the > entire series again to make progress, as it's unlikely that any maintainer > would pick up the patches from last year. > > For the contents, everything seems reasonable to me, but I noticed that > you are adding a property to the /chosen node without adding the > corresponding documentation to > Documentation/devicetree/bindings/chosen.txt > > Please add that, and Cc the devicetree maintainers on the updated > patch. > > Arnd Thanks for your review and comments, i will rebase it to linux-5.7-rc6 and add the corresponding documentation. Thanks, Chen Zhou >> On 2019/12/23 23:23, Chen Zhou wrote: >>> This patch series enable reserving crashkernel above 4G in arm64. >>> >>> There are following issues in arm64 kdump: >>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail >>> when there is no enough low memory. >>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G, >>> in this case, if swiotlb or DMA buffers are required, crash dump kernel >>> will boot failure because there is no low memory available for allocation. >>> >>> The previous changes and discussions can be retrieved from: >>> >>> Changes since [v6] >>> - Fix build errors reported by kbuild test robot. > ... > > . >
Hi John, On Wed, May 20, 2020 at 1:53 AM John Donnelly <john.p.donnelly@oracle.com> wrote: > > > > > On May 19, 2020, at 5:21 AM, Arnd Bergmann <arnd@arndb.de> wrote: > > > > On Thu, Mar 26, 2020 at 4:10 AM Chen Zhou <chenzhou10@huawei.com> wrote: > >> > >> Hi all, > >> > >> Friendly ping... > > > > I was asked about this patch series, and see that you last posted it in > > December. I think you should rebase it to linux-5.7-rc6 and post the > > entire series again to make progress, as it's unlikely that any maintainer > > would pick up the patches from last year. > > > > For the contents, everything seems reasonable to me, but I noticed that > > you are adding a property to the /chosen node without adding the > > corresponding documentation to > > Documentation/devicetree/bindings/chosen.txt > > > > Please add that, and Cc the devicetree maintainers on the updated > > patch. > > > > Arnd > > > >> On 2019/12/23 23:23, Chen Zhou wrote: > >>> This patch series enable reserving crashkernel above 4G in arm64. > >>> > >>> There are following issues in arm64 kdump: > >>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail > >>> when there is no enough low memory. > >>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G, > >>> in this case, if swiotlb or DMA buffers are required, crash dump kernel > >>> will boot failure because there is no low memory available for allocation. > >>> > >>> The previous changes and discussions can be retrieved from: > >>> > >>> Changes since [v6] > >>> - Fix build errors reported by kbuild test robot. > > ... > > > Hi > > We found > > https://lkml.org/lkml/2020/4/30/1583 > > Has cured our Out-Of-Memory kdump failures. > > From Henry Willard > Subject [PATCH] mm: Limit boost_watermark on small zones. > > I am currently not on linux-kernel@vger.kernel.org. dlist for all to see this message so you may want to rebase and see if this cures your OoM issue and share the results. This is a very interesting finding. Thanks a lot for sharing the same. I am working on further avoiding OOM issues with arm64 kdump kernels. I will experiment more with this patch and get back with more details. Regards, Bhupesh