The patch titled
Subject: mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly
has been added to the -mm tree. Its filename is
mm-make-config_deferred_struct_page_init-depends-on-flatmem-explicitly.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-make-config_deferred_struct_page_init-depends-on-flatmem-explicitly.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-make-config_deferred_struct_page_init-depends-on-flatmem-explicitly.patch
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From: Yang Shi <yang.shi@xxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1464027356-32282-1-git-send-email-yang.shi@xxxxxxxxxx
Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff -puN mm/Kconfig~mm-make-config_deferred_struct_page_init-depends-on-flatmem-explicitly mm/Kconfig
--- a/mm/Kconfig~mm-make-config_deferred_struct_page_init-depends-on-flatmem-explicitly
+++ a/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
_
Patches currently in -mm which might be from yang.shi@xxxxxxxxxx are
mm-make-config_deferred_struct_page_init-depends-on-flatmem-explicitly.patch
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