Revert "powerpc/powernv: Increase memory block size to 1GB on radix"
PATCH RESEND 1/1 Revert "powerpc/powernv: Increase memory block size to 1GB on radix"
This commit was a stop-gap to prevent crashes on hotunplug, caused by the mismatch between the 1G mappings used for the linear mapping and the memory block size. Those issues are now resolved because we split the linear mapping at hotunplug time if necessary, as implemented in commit 4dd5f8a99e79 ("powerpc/mm/radix: Split linear mapping on hot-unplug").
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arch/powerpc/platforms/powernv/setup.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-)
arch/powerpc/platforms/powernv/setup.c +1 -9
@@ -356,15 +356,7 @@ static void pnv_kexec_cpu_down(int crash_shutdown, int secondary)#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE static unsigned long pnv_memory_block_size (void ) { -/* -* We map the kernel linear region with 1GB large pages on radix. For -* memory hot unplug to work our memory block size must be at least -* this size. -*/ -if (radix_enabled ()) -return 1UL *1024 *1024 *1024 ; -else -return 256UL *1024 *1024 ; +return 256UL *1024 *1024 ; }#endif
Signature · 1 line
2.13.6
Tested hot-unplugging dimm device on radix guest on p9 host with KVM.
Quoted 8 lines · Balbir Singh
This commit was a stop-gap to prevent crashes on hotunplug, caused by the mismatch between the 1G mappings used for the linear mapping and the memory block size. Those issues are now resolved because we split the linear mapping at hotunplug time if necessary, as implemented in commit
4dd5f8a99e79("powerpc/mm/radix: Split linear mapping on hot-unplug").Signed-off-by Balbir Singh <[email protected]>Signed-off-by Michael Neuling <[email protected]>
Quoted 28 lines
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arch/powerpc/platforms/powernv/setup.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-)arch/powerpc/platforms/powernv/setup.c +1
-9@@ -356,15 +356,7 @@ static void pnv_kexec_cpu_down(int crash_shutdown, int secondary)#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE static unsigned long pnv_memory_block_size (void ) { -/* -* We map the kernel linear region with 1GB large pages on radix. For -* memory hot unplug to work our memory block size must be at least -* this size. -*/ -if (radix_enabled ()) -return 1UL *1024 *1024 *1024 ; -else -return 256UL *1024 *1024 ; +return 256UL *1024 *1024 ; }#endif
Balbir Singh
Tested-byQuoted 10 lines · On Wed, 2 May 2018 15:10:33 +1000 rashmica <[email protected]> wrote:
Tested hot-unplugging dimm device on radix guest on p9 host with KVM.
Quoted 6 lines · Balbir Singh
This commit was a stop-gap to prevent crashes on hotunplug, caused by the mismatch between the 1G mappings used for the linear mapping and the memory block size. Those issues are now resolved because we split the linear mapping at hotunplug time if necessary, as implemented in commit
4dd5f8a99e79("powerpc/mm/radix: Split linear mapping on hot-unplug").
Quoted 3 lines
Quoted 2 lines
Signed-off-by Balbir Singh <[email protected]>Signed-off-by Michael Neuling <[email protected]>Tested-by Rashmica Gupta <[email protected]>
I tested the following:
a. memtrace - enable a region smaller than 1G, which split the mappings as expected.
b. Checked linear mapping is 1G and not impacted by the revert c. I can hotplug sizes less than 1G via the probe method
Quoted 29 lines
Quoted 28 lines
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arch/powerpc/platforms/powernv/setup.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-)arch/powerpc/platforms/powernv/setup.c +1
-9@@ -356,15 +356,7 @@ static void pnv_kexec_cpu_down(int crash_shutdown, int secondary)#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE static unsigned long pnv_memory_block_size (void ) { -/* -* We map the kernel linear region with 1GB large pages on radix. For -* memory hot unplug to work our memory block size must be at least -* this size. -*/ -if (radix_enabled ()) -return 1UL *1024 *1024 *1024 ; -else -return 256UL *1024 *1024 ; +return 256UL *1024 *1024 ; }#endif
Michael Ellerman
AppliedQuoted 10 lines · Balbir Singh
This commit was a stop-gap to prevent crashes on hotunplug, caused by the mismatch between the 1G mappings used for the linear mapping and the memory block size. Those issues are now resolved because we split the linear mapping at hotunplug time if necessary, as implemented in commit
4dd5f8a99e79("powerpc/mm/radix: Split linear mapping on hot-unplug").Signed-off-by Balbir Singh <[email protected]>Signed-off-by Michael Neuling <[email protected]>Tested-by Rashmica Gupta <[email protected]>Tested-by Balbir Singh <[email protected]>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/7acf50e4efa60270edcb95107f660f
cheers