2021-03-09 10:23:55

by Pingfan Liu

[permalink] [raw]
Subject: [PATCH] drivers/arch_numa: remove rebudant setup_per_cpu_areas()

There are two identical implementations of setup_per_cpu_areas() in
mm/percpu.c and drivers/base/arch_numa.c.

Hence removing the one in arch_numa.c. And let arm64 drop
HAVE_SETUP_PER_CPU_AREA.

Signed-off-by: Pingfan Liu <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Atish Patra <[email protected]>
Cc: [email protected]
To: [email protected]
---
arch/arm64/Kconfig | 4 ----
drivers/base/arch_numa.c | 22 ----------------------
2 files changed, 26 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1f212b47a48a..d4bf8be0c3d5 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1022,10 +1022,6 @@ config USE_PERCPU_NUMA_NODE_ID
def_bool y
depends on NUMA

-config HAVE_SETUP_PER_CPU_AREA
- def_bool y
- depends on NUMA
-
config NEED_PER_CPU_EMBED_FIRST_CHUNK
def_bool y
depends on NUMA
diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
index 4cc4e117727d..23e1e419a83d 100644
--- a/drivers/base/arch_numa.c
+++ b/drivers/base/arch_numa.c
@@ -167,28 +167,6 @@ static void __init pcpu_fc_free(void *ptr, size_t size)
{
memblock_free_early(__pa(ptr), size);
}
-
-void __init setup_per_cpu_areas(void)
-{
- unsigned long delta;
- unsigned int cpu;
- int rc;
-
- /*
- * Always reserve area for module percpu variables. That's
- * what the legacy allocator did.
- */
- rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
- PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
- pcpu_cpu_distance,
- pcpu_fc_alloc, pcpu_fc_free);
- if (rc < 0)
- panic("Failed to initialize percpu areas.");
-
- delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
- for_each_possible_cpu(cpu)
- __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
-}
#endif

/**
--
2.29.2


2021-03-09 14:04:10

by Will Deacon

[permalink] [raw]
Subject: Re: [PATCH] drivers/arch_numa: remove rebudant setup_per_cpu_areas()

[typo in subject "rebudant"]

On Tue, Mar 09, 2021 at 06:21:38PM +0800, Pingfan Liu wrote:
> There are two identical implementations of setup_per_cpu_areas() in
> mm/percpu.c and drivers/base/arch_numa.c.
>
> Hence removing the one in arch_numa.c. And let arm64 drop
> HAVE_SETUP_PER_CPU_AREA.
>
> Signed-off-by: Pingfan Liu <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: Atish Patra <[email protected]>
> Cc: [email protected]
> To: [email protected]
> ---
> arch/arm64/Kconfig | 4 ----
> drivers/base/arch_numa.c | 22 ----------------------
> 2 files changed, 26 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 1f212b47a48a..d4bf8be0c3d5 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1022,10 +1022,6 @@ config USE_PERCPU_NUMA_NODE_ID
> def_bool y
> depends on NUMA
>
> -config HAVE_SETUP_PER_CPU_AREA
> - def_bool y
> - depends on NUMA
> -
> config NEED_PER_CPU_EMBED_FIRST_CHUNK
> def_bool y
> depends on NUMA
> diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
> index 4cc4e117727d..23e1e419a83d 100644
> --- a/drivers/base/arch_numa.c
> +++ b/drivers/base/arch_numa.c
> @@ -167,28 +167,6 @@ static void __init pcpu_fc_free(void *ptr, size_t size)
> {
> memblock_free_early(__pa(ptr), size);
> }
> -
> -void __init setup_per_cpu_areas(void)
> -{
> - unsigned long delta;
> - unsigned int cpu;
> - int rc;
> -
> - /*
> - * Always reserve area for module percpu variables. That's
> - * what the legacy allocator did.
> - */
> - rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
> - PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
> - pcpu_cpu_distance,
> - pcpu_fc_alloc, pcpu_fc_free);

This doesn't look identical to the version in mm/percpu.c -- that one passes
NULL instead of 'pcpu_cpu_distance' and tries to allocate the pcpu memory on
the relevant NUMA nodes. In fact, if you could remove this function, you
could probably remove the whole HAVE_SETUP_PER_CPU_AREA block here as the
other functions are just used as helpers. So I'm not sure this is valid.

Will

2021-03-10 04:07:15

by Pingfan Liu

[permalink] [raw]
Subject: Re: [PATCH] drivers/arch_numa: remove rebudant setup_per_cpu_areas()

On Tue, Mar 9, 2021 at 10:02 PM Will Deacon <[email protected]> wrote:
>
> [typo in subject "rebudant"]
>
> On Tue, Mar 09, 2021 at 06:21:38PM +0800, Pingfan Liu wrote:
> > There are two identical implementations of setup_per_cpu_areas() in
> > mm/percpu.c and drivers/base/arch_numa.c.
> >
> > Hence removing the one in arch_numa.c. And let arm64 drop
> > HAVE_SETUP_PER_CPU_AREA.
> >
> > Signed-off-by: Pingfan Liu <[email protected]>
> > Cc: Catalin Marinas <[email protected]>
> > Cc: Will Deacon <[email protected]>
> > Cc: Greg Kroah-Hartman <[email protected]>
> > Cc: "Rafael J. Wysocki" <[email protected]>
> > Cc: Atish Patra <[email protected]>
> > Cc: [email protected]
> > To: [email protected]
> > ---
> > arch/arm64/Kconfig | 4 ----
> > drivers/base/arch_numa.c | 22 ----------------------
> > 2 files changed, 26 deletions(-)
> >
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 1f212b47a48a..d4bf8be0c3d5 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -1022,10 +1022,6 @@ config USE_PERCPU_NUMA_NODE_ID
> > def_bool y
> > depends on NUMA
> >
> > -config HAVE_SETUP_PER_CPU_AREA
> > - def_bool y
> > - depends on NUMA
> > -
> > config NEED_PER_CPU_EMBED_FIRST_CHUNK
> > def_bool y
> > depends on NUMA
> > diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
> > index 4cc4e117727d..23e1e419a83d 100644
> > --- a/drivers/base/arch_numa.c
> > +++ b/drivers/base/arch_numa.c
> > @@ -167,28 +167,6 @@ static void __init pcpu_fc_free(void *ptr, size_t size)
> > {
> > memblock_free_early(__pa(ptr), size);
> > }
> > -
> > -void __init setup_per_cpu_areas(void)
> > -{
> > - unsigned long delta;
> > - unsigned int cpu;
> > - int rc;
> > -
> > - /*
> > - * Always reserve area for module percpu variables. That's
> > - * what the legacy allocator did.
> > - */
> > - rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
> > - PERCPU_DYNAMIC_RESERVE, PAGE_SIZE,
> > - pcpu_cpu_distance,
> > - pcpu_fc_alloc, pcpu_fc_free);
>
> This doesn't look identical to the version in mm/percpu.c -- that one passes
> NULL instead of 'pcpu_cpu_distance' and tries to allocate the pcpu memory on
> the relevant NUMA nodes. In fact, if you could remove this function, you
> could probably remove the whole HAVE_SETUP_PER_CPU_AREA block here as the
> other functions are just used as helpers. So I'm not sure this is valid.
>
You are right. I need to rethink about it to see whether these two
functions can be unified into one.

Thanks,
Pingfan