path: root/arch
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authorAnton Blanchard <anton@samba.org>2017-09-07 15:05:51 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2017-10-06 15:50:45 +1100
commit53ecde0b9126ff140abe3aefd7f0ec64d6fa36b0 (patch)
treeab26139c678e18ccd591ac651e1456868ac5cb18 /arch
parentpowerpc/mm: Call flush_tlb_kernel_range with interrupts enabled (diff)
powerpc/powernv: Increase memory block size to 1GB on radix
Memory hot unplug on PowerNV radix hosts is broken. Our memory block size is 256MB but since we map the linear region with very large pages, each pte we tear down maps 1GB. A hot unplug of one 256MB memory block results in 768MB of memory getting unintentionally unmapped. At this point we are likely to oops. Fix this by increasing our memory block size to 1GB on PowerNV radix hosts. Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()") Cc: stable@vger.kernel.org # v4.11+ Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 897aa1400eb8..bbb73aa0eb8f 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -272,7 +272,15 @@ static void pnv_kexec_cpu_down(int crash_shutdown, int secondary)
static unsigned long pnv_memory_block_size(void)
- return 256UL * 1024 * 1024;
+ /*
+ * 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;