From f4eb07c17df2e6cf9bd58bfcd9cc9e05e9489d07 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Fri, 8 Dec 2006 15:56:07 +0100 Subject: [S390] Virtual memmap for s390. Virtual memmap support for s390. Inspired by the ia64 implementation. Unlike ia64 we need a mechanism which allows us to dynamically attach shared memory regions. These memory regions are accessed via the dcss device driver. dcss implements the 'direct_access' operation, which requires struct pages for every single shared page. Therefore this implementation provides an interface to attach/detach shared memory: int add_shared_memory(unsigned long start, unsigned long size); int remove_shared_memory(unsigned long start, unsigned long size); The purpose of the add_shared_memory function is to add the given memory range to the 1:1 mapping and to make sure that the corresponding range in the vmemmap is backed with physical pages. It also initialises the new struct pages. remove_shared_memory in turn only invalidates the page table entries in the 1:1 mapping. The page tables and the memory used for struct pages in the vmemmap are currently not freed. They will be reused when the next segment will be attached. Given that the maximum size of a shared memory region is 2GB and in addition all regions must reside below 2GB this is not too much of a restriction, but there is room for improvement. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/s390/kernel/setup.c') diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index b928fecdc743..b8a1ce215142 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -64,7 +64,7 @@ unsigned int console_devno = -1; unsigned int console_irq = -1; unsigned long machine_flags = 0; -struct mem_chunk memory_chunk[MEMORY_CHUNKS]; +struct mem_chunk __initdata memory_chunk[MEMORY_CHUNKS]; volatile int __cpu_logical_map[NR_CPUS]; /* logical cpu to cpu address */ unsigned long __initdata zholes_size[MAX_NR_ZONES]; static unsigned long __initdata memory_end; -- cgit v1.2.3