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

BugLink: http://bugs.launchpad.net/bugs/1807469
commit d7609f4210cb716c11abfe2bfb5997191095d00b upstream.

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 <mike.travis@hpe.com>
Reviewed-by: Andrew Banman <andrew.banman@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dan.j.williams@intel.com
Cc: jgross@suse.com
Cc: kirill.shutemov@linux.intel.com
Cc: mhocko@suse.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/lkml/20180524201711.854849120@stormcage.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index 4a3dd78f54060f418f19da7c06304e8d9ebd0a54..f8a5f140ea5efeb3b582e52df95302058cf785a4 100644 (file)
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -393,6 +393,17 @@ 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;