diff mbox series

[V4,4/4] LoongArch: Enable ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP

Message ID 20220704112526.2492342-5-chenhuacai@loongson.cn (mailing list archive)
State New, archived
Headers show
Series mm/sparse-vmemmap: Generalise helpers and enable for LoongArch | expand

Commit Message

Huacai Chen July 4, 2022, 11:25 a.m. UTC 
From: Feiyang Chen <chenfeiyang@loongson.cn>

The feature of minimizing overhead of struct page associated with each
HugeTLB page is implemented on x86_64. However, the infrastructure of
this feature is already there, so just select ARCH_WANT_HUGETLB_PAGE_
OPTIMIZE_VMEMMAP is enough to enable this feature for LoongArch.

To avoid the following build error on LoongArch we should include linux/
static_key.h in page-flags.h.

In file included from ./include/linux/mmzone.h:22,
from ./include/linux/gfp.h:6,
from ./include/linux/mm.h:7,
from arch/loongarch/kernel/asm-offsets.c:9:
./include/linux/page-flags.h:208:1: warning: data definition has no
type or storage class
208 | DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
| ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=implicit-int]
./include/linux/page-flags.h:209:26: warning: parameter names (without
types) in function declaration
209 | hugetlb_optimize_vmemmap_key);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/page-flags.h: In function 'hugetlb_optimize_vmemmap_enabled':
./include/linux/page-flags.h:213:16: error: implicit declaration of
function 'static_branch_maybe' [-Werror=implicit-function-declaration]
213 | return static_branch_maybe(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
| ^~~~~~~~~~~~~~~~~~~
./include/linux/page-flags.h:213:36: error:
'CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON' undeclared (first
use in this function); did you mean
'CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP'?
213 | return static_branch_maybe(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
./include/linux/page-flags.h:213:36: note: each undeclared identifier
is reported only once for each function it appears in
./include/linux/page-flags.h:214:37: error:
'hugetlb_optimize_vmemmap_key' undeclared (first use in this
function); did you mean 'hugetlb_optimize_vmemmap_enabled'?
214 | &hugetlb_optimize_vmemmap_key);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
| hugetlb_optimize_vmemmap_enabled

Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
 arch/loongarch/Kconfig     | 1 +
 include/linux/page-flags.h | 1 +
 2 files changed, 2 insertions(+)

Comments

Arnd Bergmann July 4, 2022, 12:18 p.m. UTC | #1 
On Mon, Jul 4, 2022 at 1:25 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
> To avoid the following build error on LoongArch we should include linux/
> static_key.h in page-flags.h.
>
> In file included from ./include/linux/mmzone.h:22,
> from ./include/linux/gfp.h:6,
> from ./include/linux/mm.h:7,
> from arch/loongarch/kernel/asm-offsets.c:9:
> ./include/linux/page-flags.h:208:1: warning: data definition has no
> type or storage class
> 208 | DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
> | ^~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
> declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=implicit-int]
> ./include/linux/page-flags.h:209:26: warning: parameter names (without
> types) in function declaration

I wonder if page_fixed_fake_head() should be moved out of line to avoid
this, it's already nontrivial here, and that would avoid the static key
in a central header.

       Arnd
Huacai Chen July 5, 2022, 6:21 a.m. UTC | #2 
Hi, Arnd,

On Mon, Jul 4, 2022 at 8:18 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Mon, Jul 4, 2022 at 1:25 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
> > To avoid the following build error on LoongArch we should include linux/
> > static_key.h in page-flags.h.
> >
> > In file included from ./include/linux/mmzone.h:22,
> > from ./include/linux/gfp.h:6,
> > from ./include/linux/mm.h:7,
> > from arch/loongarch/kernel/asm-offsets.c:9:
> > ./include/linux/page-flags.h:208:1: warning: data definition has no
> > type or storage class
> > 208 | DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
> > | ^~~~~~~~~~~~~~~~~~~~~~~~
> > ./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
> > declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=implicit-int]
> > ./include/linux/page-flags.h:209:26: warning: parameter names (without
> > types) in function declaration
>
> I wonder if page_fixed_fake_head() should be moved out of line to avoid
> this, it's already nontrivial here, and that would avoid the static key
> in a central header.
I have some consideration here. I think both inline function and
static key are instruments to make things faster, in other words,
page_fixed_fake_head() is a performance critical function. If so, it
is not suitable to move it out of line.

Huacai
>
>        Arnd
>
Muchun Song July 5, 2022, 7:51 a.m. UTC | #3 
On Tue, Jul 5, 2022 at 2:22 PM Huacai Chen <chenhuacai@kernel.org> wrote:
>
> Hi, Arnd,
>
> On Mon, Jul 4, 2022 at 8:18 PM Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > On Mon, Jul 4, 2022 at 1:25 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
> > > To avoid the following build error on LoongArch we should include linux/
> > > static_key.h in page-flags.h.
> > >
> > > In file included from ./include/linux/mmzone.h:22,
> > > from ./include/linux/gfp.h:6,
> > > from ./include/linux/mm.h:7,
> > > from arch/loongarch/kernel/asm-offsets.c:9:
> > > ./include/linux/page-flags.h:208:1: warning: data definition has no
> > > type or storage class
> > > 208 | DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
> > > | ^~~~~~~~~~~~~~~~~~~~~~~~
> > > ./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
> > > declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=implicit-int]
> > > ./include/linux/page-flags.h:209:26: warning: parameter names (without
> > > types) in function declaration
> >
> > I wonder if page_fixed_fake_head() should be moved out of line to avoid
> > this, it's already nontrivial here, and that would avoid the static key
> > in a central header.
> I have some consideration here. I think both inline function and
> static key are instruments to make things faster, in other words,
> page_fixed_fake_head() is a performance critical function. If so, it
> is not suitable to move it out of line.

+1

The static key is an optimization when HVO is disabled.

Thanks.

>
> Huacai
> >
> >        Arnd
> >
Arnd Bergmann July 5, 2022, 8:05 a.m. UTC | #4 
On Tue, Jul 5, 2022 at 9:51 AM Muchun Song <songmuchun@bytedance.com> wrote:
>
> On Tue, Jul 5, 2022 at 2:22 PM Huacai Chen <chenhuacai@kernel.org> wrote:
> >
> > Hi, Arnd,
> >
> > On Mon, Jul 4, 2022 at 8:18 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > >
> > > On Mon, Jul 4, 2022 at 1:25 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
> > > > To avoid the following build error on LoongArch we should include linux/
> > > > static_key.h in page-flags.h.
> > > >
> > > > In file included from ./include/linux/mmzone.h:22,
> > > > from ./include/linux/gfp.h:6,
> > > > from ./include/linux/mm.h:7,
> > > > from arch/loongarch/kernel/asm-offsets.c:9:
> > > > ./include/linux/page-flags.h:208:1: warning: data definition has no
> > > > type or storage class
> > > > 208 | DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
> > > > | ^~~~~~~~~~~~~~~~~~~~~~~~
> > > > ./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
> > > > declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=implicit-int]
> > > > ./include/linux/page-flags.h:209:26: warning: parameter names (without
> > > > types) in function declaration
> > >
> > > I wonder if page_fixed_fake_head() should be moved out of line to avoid
> > > this, it's already nontrivial here, and that would avoid the static key
> > > in a central header.
> > I have some consideration here. I think both inline function and
> > static key are instruments to make things faster, in other words,
> > page_fixed_fake_head() is a performance critical function. If so, it
> > is not suitable to move it out of line.
>
> +1
>
> The static key is an optimization when HVO is disabled.

How about splitting up linux/page_flags.h so the static_key header is
only included
in those places that use one of the inline functions that depend on it?

       Arnd
Muchun Song July 5, 2022, 8:38 a.m. UTC | #5 
On Tue, Jul 5, 2022 at 4:06 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Tue, Jul 5, 2022 at 9:51 AM Muchun Song <songmuchun@bytedance.com> wrote:
> >
> > On Tue, Jul 5, 2022 at 2:22 PM Huacai Chen <chenhuacai@kernel.org> wrote:
> > >
> > > Hi, Arnd,
> > >
> > > On Mon, Jul 4, 2022 at 8:18 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > > >
> > > > On Mon, Jul 4, 2022 at 1:25 PM Huacai Chen <chenhuacai@loongson.cn> wrote:
> > > > > To avoid the following build error on LoongArch we should include linux/
> > > > > static_key.h in page-flags.h.
> > > > >
> > > > > In file included from ./include/linux/mmzone.h:22,
> > > > > from ./include/linux/gfp.h:6,
> > > > > from ./include/linux/mm.h:7,
> > > > > from arch/loongarch/kernel/asm-offsets.c:9:
> > > > > ./include/linux/page-flags.h:208:1: warning: data definition has no
> > > > > type or storage class
> > > > > 208 | DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
> > > > > | ^~~~~~~~~~~~~~~~~~~~~~~~
> > > > > ./include/linux/page-flags.h:208:1: error: type defaults to 'int' in
> > > > > declaration of 'DECLARE_STATIC_KEY_MAYBE' [-Werror=implicit-int]
> > > > > ./include/linux/page-flags.h:209:26: warning: parameter names (without
> > > > > types) in function declaration
> > > >
> > > > I wonder if page_fixed_fake_head() should be moved out of line to avoid
> > > > this, it's already nontrivial here, and that would avoid the static key
> > > > in a central header.
> > > I have some consideration here. I think both inline function and
> > > static key are instruments to make things faster, in other words,
> > > page_fixed_fake_head() is a performance critical function. If so, it
> > > is not suitable to move it out of line.
> >
> > +1
> >
> > The static key is an optimization when HVO is disabled.
>
> How about splitting up linux/page_flags.h so the static_key header is
> only included
> in those places that use one of the inline functions that depend on it?
>

How about including the static key header in the scope of
CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP?

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 465ff35a8c00..4dd005ad43fc 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -205,6 +205,8 @@ enum pageflags {
 #ifndef __GENERATING_BOUNDS_H

 #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
+#include <linux/static_key.h>
+
 DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key);

 /*
Arnd Bergmann July 5, 2022, 8:45 a.m. UTC | #6 
On Tue, Jul 5, 2022 at 10:38 AM Muchun Song <songmuchun@bytedance.com> wrote:
> On Tue, Jul 5, 2022 at 4:06 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > On Tue, Jul 5, 2022 at 9:51 AM Muchun Song <songmuchun@bytedance.com> wrote:
>
> How about including the static key header in the scope of
> CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP?

That helps a little, but it means we still pay for it on x86 and
arm64, which are the
most common architectures.

       Arnd
Muchun Song July 5, 2022, 9:12 a.m. UTC | #7 
On Tue, Jul 5, 2022 at 4:46 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Tue, Jul 5, 2022 at 10:38 AM Muchun Song <songmuchun@bytedance.com> wrote:
> > On Tue, Jul 5, 2022 at 4:06 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > > On Tue, Jul 5, 2022 at 9:51 AM Muchun Song <songmuchun@bytedance.com> wrote:
> >
> > How about including the static key header in the scope of
> > CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP?
>
> That helps a little, but it means we still pay for it on x86 and
> arm64, which are the
> most common architectures.

Alright. Make sense.

>
>        Arnd
Feiyang Chen July 5, 2022, 10:49 a.m. UTC | #8 
On Tue, 5 Jul 2022 at 16:45, Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Tue, Jul 5, 2022 at 10:38 AM Muchun Song <songmuchun@bytedance.com> wrote:
> > On Tue, Jul 5, 2022 at 4:06 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > > On Tue, Jul 5, 2022 at 9:51 AM Muchun Song <songmuchun@bytedance.com> wrote:
> >
> > How about including the static key header in the scope of
> > CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP?
>
> That helps a little, but it means we still pay for it on x86 and
> arm64, which are the
> most common architectures.
>

Hi, Arnd,

It seems that arm64 and x86 include static_key.h or jump_label.h in some
more basic header files, otherwise they would not compile successfully
when they including page-flags.h.

In file included from ./arch/arm64/include/asm/lse.h:13,
from ./arch/arm64/include/asm/cmpxchg.h:14,
from ./arch/arm64/include/asm/atomic.h:16,
from ./include/linux/atomic.h:7,
from ./include/asm-generic/bitops/atomic.h:5,
from ./arch/arm64/include/asm/bitops.h:25,
from ./include/linux/bitops.h:33,
from ./include/linux/log2.h:12,
from kernel/bounds.c:13:
./include/linux/jump_label.h:5:2: error: #error "Hi"
5 | #error "Hi"

In file included from ./arch/x86/include/asm/nospec-branch.h:6,
from ./arch/x86/include/asm/paravirt_types.h:40,
from ./arch/x86/include/asm/ptrace.h:97,
from ./arch/x86/include/asm/math_emu.h:5,
from ./arch/x86/include/asm/processor.h:13,
from ./arch/x86/include/asm/cpufeature.h:5,
from ./arch/x86/include/asm/thread_info.h:53,
from ./include/linux/thread_info.h:60,
from ./arch/x86/include/asm/preempt.h:7,
from ./include/linux/preempt.h:78,
from ./include/linux/spinlock.h:55,
from ./include/linux/mmzone.h:8,
from ./include/linux/gfp.h:6,
from ./include/linux/slab.h:15,
from ./include/linux/crypto.h:20,
from arch/x86/kernel/asm-offsets.c:9:
./include/linux/static_key.h:3:2: error: #error "Hi"
#error "Hi"
^~~~~
In file included from ./include/linux/tracepoint-defs.h:12,
from ./arch/x86/include/asm/msr.h:58,
from ./arch/x86/include/asm/processor.h:22,
from ./arch/x86/include/asm/cpufeature.h:5,
from ./arch/x86/include/asm/thread_info.h:53,
from ./include/linux/thread_info.h:60,
from ./arch/x86/include/asm/preempt.h:7,
from ./include/linux/preempt.h:78,
from ./include/linux/spinlock.h:55,
from ./include/linux/mmzone.h:8,
from ./include/linux/gfp.h:6,
from ./include/linux/slab.h:15,
from ./include/linux/crypto.h:20,
from arch/x86/kernel/asm-offsets.c:9:
./include/linux/static_key.h:3:2: error: #error "Hi"
#error "Hi"
^~~~~
In file included from ./include/linux/kasan-enabled.h:5,
from ./include/linux/kasan.h:6,
from ./include/linux/slab.h:140,
from ./include/linux/crypto.h:20,
from arch/x86/kernel/asm-offsets.c:9:
./include/linux/static_key.h:3:2: error: #error "Hi"
#error "Hi"
^~~~~
In file included from ./include/linux/kasan.h:8,
from ./include/linux/slab.h:140,
from ./include/linux/crypto.h:20,
from arch/x86/kernel/asm-offsets.c:9:
./include/linux/static_key.h:3:2: error: #error "Hi"
#error "Hi"
^~~~~
In file included from ./include/linux/context_tracking_state.h:6,
from ./include/linux/hardirq.h:5,
from arch/x86/kernel/asm-offsets.c:12:
./include/linux/static_key.h:3:2: error: #error "Hi"
#error "Hi"
^~~~~
In file included from ./include/linux/vmstat.h:10,
from ./include/linux/mm.h:1771,
from ./include/linux/memcontrol.h:20,
from ./include/linux/swap.h:9,
from ./include/linux/suspend.h:5,
from arch/x86/kernel/asm-offsets.c:13:
./include/linux/static_key.h:3:2: error: #error "Hi"
#error "Hi"

Thanks,
Feiyang

>        Arnd
>
diff mbox series

Patch

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 55ab84fd70e5..8e56ca28165e 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -49,6 +49,7 @@  config LOONGARCH
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
+	select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
 	select ARCH_WANTS_NO_INSTR
 	select BUILDTIME_TABLE_SORT
 	select COMMON_CLK
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index e66f7aa3191d..28a53ac7aa3e 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -9,6 +9,7 @@ 
 #include <linux/types.h>
 #include <linux/bug.h>
 #include <linux/mmdebug.h>
+#include <linux/static_key.h>
 #ifndef __GENERATING_BOUNDS_H
 #include <linux/mm_types.h>
 #include <generated/bounds.h>