powerpc: Don't flush caches when adding memory

This operation takes a significant amount of time when hotplugging
large amounts of memory (~50 seconds with 890GB of persistent memory).

This was orignally in commit fb5924fddf9e
("powerpc/mm: Flush cache on memory hot(un)plug") to support memtrace,
but the flush on add is not needed as it is flushed on remove.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191104023305.9581-7-alastair@au1.ibm.com

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 634e5ea..7573002 100644 (file)
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -142,8 +142,6 @@ int __ref arch_add_memory(int nid, u64 start, u64 size,
                return -EFAULT;
        }
 
-       flush_dcache_range_chunked(start, start + size, FLUSH_CHUNK_SIZE);
-
        return __add_pages(nid, start_pfn, nr_pages, restrictions);
 }