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Groups > linux.kernel > #1405530 > unrolled thread
| Started by | Yang Shi <yang.shi@linaro.org> |
|---|---|
| First post | 2016-05-23 19:30 +0200 |
| Last post | 2016-05-23 20:40 +0200 |
| Articles | 3 — 3 participants |
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[PATCH] mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly Yang Shi <yang.shi@linaro.org> - 2016-05-23 19:30 +0200
Re: [PATCH] mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly Michal Hocko <mhocko@kernel.org> - 2016-05-23 20:30 +0200
Re: [PATCH] mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly "Shi, Yang" <yang.shi@linaro.org> - 2016-05-23 20:40 +0200
| From | Yang Shi <yang.shi@linaro.org> |
|---|---|
| Date | 2016-05-23 19:30 +0200 |
| Subject | [PATCH] mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly |
| Message-ID | <rC1PX-k3-1@gated-at.bofh.it> |
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(+) 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
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| From | Michal Hocko <mhocko@kernel.org> |
|---|---|
| Date | 2016-05-23 20:30 +0200 |
| Subject | Re: [PATCH] mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly |
| Message-ID | <rC2M2-WM-15@gated-at.bofh.it> |
| In reply to | #1405530 |
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 " > > [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 -- Michal Hocko SUSE Labs
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| From | "Shi, Yang" <yang.shi@linaro.org> |
|---|---|
| Date | 2016-05-23 20:40 +0200 |
| Subject | Re: [PATCH] mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly |
| Message-ID | <rC2VI-ZT-17@gated-at.bofh.it> |
| In reply to | #1405561 |
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 >
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