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authorHeiko Carstens <heiko.carstens@de.ibm.com>2006-12-08 15:56:07 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2006-12-08 15:56:07 +0100
commitf4eb07c17df2e6cf9bd58bfcd9cc9e05e9489d07 (patch)
treec1b4b422d3b8183edf452cc745dadd0fe129018b /arch/s390/Kconfig
parent7f090145a14afc35844dce80174c9c24f9e66ec5 (diff)
[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 <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/Kconfig')
-rw-r--r--arch/s390/Kconfig3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index a08e9100e7e..f12ca8fba71 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -235,6 +235,9 @@ config WARN_STACK_SIZE
source "mm/Kconfig"
+config HOLES_IN_ZONE
+ def_bool y
+
comment "I/O subsystem configuration"
config MACHCHK_WARNING