| Message ID | 1464022471-30545-1-git-send-email-yang.shi@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On 5/23/2016 11:22 AM, Michal Hocko wrote: > On Mon 23-05-16 09:54:31, Yang Shi wrote: >> Per the suggestion from Michal Hocko [1], CONFIG_DEFERRED_STRUCT_PAGE_INIT >> should be incompatible with FLATMEM, make this explicitly in Kconfig. > > I guess the changelog could benefit from some clarification. What > do you think about the following: > > " > 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 > " Thanks a lot. It sounds way better. Will address in V2. Yang > >> >> [1] http://lkml.kernel.org/r/20160523073157.GD2278@dhcp22.suse.cz >> >> Signed-off-by: Yang Shi <yang.shi@linaro.org> >> --- >> mm/Kconfig | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/mm/Kconfig b/mm/Kconfig >> index 2664c11..22fa818 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 >> -- >> 2.0.2 >
diff --git a/mm/Kconfig b/mm/Kconfig index 2664c11..22fa818 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
Per the suggestion from Michal Hocko [1], CONFIG_DEFERRED_STRUCT_PAGE_INIT should be incompatible with FLATMEM, make this explicitly in Kconfig. [1] http://lkml.kernel.org/r/20160523073157.GD2278@dhcp22.suse.cz Signed-off-by: Yang Shi <yang.shi@linaro.org> --- mm/Kconfig | 1 + 1 file changed, 1 insertion(+) -- 2.0.2