x86/platform/UV: Add kernel parameter to set memory block size

Add a kernel parameter that allows setting UV memory block size.  This
is to provide an adjustment for new forms of PMEM and other DIMM memory
that might require alignment restrictions other than scanning the global
address table for the required minimum alignment.  The value set will be
further adjusted by both the GAM range table scan as well as restrictions
imposed by set_memory_block_size_order().

Signed-off-by: Mike Travis <[email protected]>
Reviewed-by: Andrew Banman <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Dimitri Sivanich <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Russ Anderson <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/lkml/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 2270a777d64767b62be7ce7a4f2e29d55dd59b42..d492752f79e1b9f120de025a9fa89b692e720705 100644 (file)
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -396,6 +396,17 @@ EXPORT_SYMBOL(uv_hub_info_version);
 /* Default UV memory block size is 2GB */
 static unsigned long mem_block_size = (2UL << 30);
 
+/* Kernel parameter to specify UV mem block size */
+static int parse_mem_block_size(char *ptr)
+{
+       unsigned long size = memparse(ptr, NULL);
+
+       /* Size will be rounded down by set_block_size() below */
+       mem_block_size = size;
+       return 0;
+}
+early_param("uv_memblksize", parse_mem_block_size);
+
 static __init int adj_blksize(u32 lgre)
 {
        unsigned long base = (unsigned long)lgre << UV_GAM_RANGE_SHFT;