On 28/01/22 3:34 pm, Sourabh Jain wrote:
On large config LPARs (having 192 and more cores), Linux fails to boot
due to insufficient memory in the first memblock. It is due to the
memory reservation for the crash kernel which starts at 128MB offset of
the first memblock. This memory reservation for the crash kernel doesn't
leave enough space in the first memblock to accommodate other essential
system resources.
The crash kernel start address was set to 128MB offset by default to
ensure that the crash kernel get some memory below the RMA region which
is used to be of size 256MB. But given that the RMA region size can be
512MB or more, setting the crash kernel offset to mid of RMA size will
leave enough space for kernel to allocate memory for other system
resources.
Since the above crash kernel offset change is only applicable to the LPAR
platform, the LPAR feature detection is pushed before the crash kernel
reservation. The rest of LPAR specific initialization will still
be done during pseries_probe_fw_features as usual.
Signed-off-by: Sourabh Jain<sourabhj...@linux.ibm.com>
Reported-and-tested-by: Abdul haleem<abdha...@linux.vnet.ibm.com>
---
arch/powerpc/kernel/rtas.c | 4 ++++
arch/powerpc/kexec/core.c | 15 +++++++++++----
2 files changed, 15 insertions(+), 4 deletions(-)
---
Change in v3:
Dropped 1st and 2nd patch from v2. 1st and 2nd patch from v2 patch
series [1] try to discover 1T segment MMU feature support
BEFORE boot CPU paca allocation ([1] describes why it is needed).
MPE has posted a patch [2] that archives a similar objective by moving
boot CPU paca allocation after mmu_early_init_devtree().
NOTE: This patch is dependent on the patch [2].
[1]https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20211018084434.217772-3-sourabhj...@linux.ibm.com/
[2]https://lists.ozlabs.org/pipermail/linuxppc-dev/2022-January/239175.html
This dependency info must be captured somewhere within the changelog to
be useful.
