diff options
author | Yang Shi <yang.shi@linaro.org> | 2016-05-24 10:03:50 +1000 |
---|---|---|
committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2016-05-24 15:27:54 +1000 |
commit | 0fb08b9596bc315b887fa5b2f80c1404acab792f (patch) | |
tree | e118728c0fd44e88afbf818e1865471400126a94 | |
parent | c35f6a51456bf5ddf771cd5285f2aee97ecd3f40 (diff) | |
download | linux-next-0fb08b9596bc315b887fa5b2f80c1404acab792f.tar.gz |
mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly
Per the suggestion from Michal Hocko [1], DEFERRED_STRUCT_PAGE_INIT
requires some ordering wrt other initialization operations, e.g.
page_ext_init has to happen after the whole memmap is initialized
properly. For SPARSEMEM this requires to wait for page_alloc_init_late.
Other memory models (e.g. flatmem) might have different initialization
layouts (page_ext_init_flatmem). Currently DEFERRED_STRUCT_PAGE_INIT
depends on MEMORY_HOTPLUG which in turn
depends on SPARSEMEM || X86_64_ACPI_NUMA
depends on ARCH_ENABLE_MEMORY_HOTPLUG
and X86_64_ACPI_NUMA depends on NUMA which in turn disable FLATMEM memory
model:
config ARCH_FLATMEM_ENABLE
def_bool y
depends on X86_32 && !NUMA
so FLATMEM is ruled out via dependency maze. Be explicit and disable
FLATMEM for DEFERRED_STRUCT_PAGE_INIT so that we do not reintroduce subtle
initialization bugs
[1] http://lkml.kernel.org/r/20160523073157.GD2278@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/1464027356-32282-1-git-send-email-yang.shi@linaro.org
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r-- | mm/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index 2664c118b5d2..22fa8189e4fc 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -649,6 +649,7 @@ config DEFERRED_STRUCT_PAGE_INIT default n depends on ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT depends on MEMORY_HOTPLUG + depends on !FLATMEM help Ordinarily all struct pages are initialised during early boot in a single thread. On very large machines this can take a considerable |