x86/mm: Remove the redundant conditional check

PATCH Applied Baoquan He 4 participants 7 messages Mar 11, 2020 – Mar 18, 2020

Subsystems (3)

Memory management x86 x86 MM

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Baoquan He

author

2020-03-11 01:18 UTC #0 lore raw

PATCH v2 1/1 x86/mm: Remove the redundant conditional check

In commit f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"), the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before commit f70029bbaacb, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make (N_MEMORY == N_NORMAL_MEMORY) be true. After commit f70029bbaacb, N_MEMORY doesn't have any chance to be equal to N_NORMAL_MEMORY. So the conditional check in paging_init() doesn't make sense any more. Let's remove it.

Signed-off-by Baoquan He <[email protected]>

---
v1->v2:
Update patch log to make the description clearer per Michal's suggestion.

 arch/x86/mm/init_64.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

arch/x86/mm/init_64.c +1 -2

index abbdecb75fad..0a14711d3a93 100644
@@ -818,8 +818,7 @@ void __init paging_init(void)
 	 *	 will not set it back.
 	 */
 	node_clear_state(0, N_MEMORY);
-	if (N_MEMORY != N_NORMAL_MEMORY)
-		node_clear_state(0, N_NORMAL_MEMORY);
+	node_clear_state(0, N_NORMAL_MEMORY);
 
 	zone_sizes_init();
 }

Signature · 1 line

2.17.2

Michal Hocko

Acked-by on v2 1/1

2020-03-11 09:27 UTC #1 lore raw

Quoted 8 lines · Baoquan He

In commit f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"), the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before commit f70029bbaacb, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make (N_MEMORY == N_NORMAL_MEMORY) be true. After commit f70029bbaacb, N_MEMORY doesn't have any chance to be equal to N_NORMAL_MEMORY. So the conditional check in paging_init() doesn't make sense any more. Let's remove it.
Signed-off-by Baoquan He <[email protected]>

Acked-by Michal Hocko <[email protected]>

Thanks!

Quoted 24 lines

---
v1->v2:
Update patch log to make the description clearer per Michal's suggestion.

 arch/x86/mm/init_64.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

arch/x86/mm/init_64.c +1 -2

index abbdecb75fad..0a14711d3a93 100644
@@ -818,8 +818,7 @@ void __init paging_init(void)
 	 *	 will not set it back.
 	 */
 	node_clear_state(0, N_MEMORY);
-	if (N_MEMORY != N_NORMAL_MEMORY)
-		node_clear_state(0, N_NORMAL_MEMORY);
+	node_clear_state(0, N_NORMAL_MEMORY);
 
 	zone_sizes_init();
 }

Signature · 1 line

2.17.2

Signature · 2 lines

Michal Hocko
SUSE Labs

Wei Yang

Reviewed-by on v2 1/1

2020-03-14 15:10 UTC #2 lore raw

In reply to Baoquan He

Quoted 8 lines · Baoquan He

In commit f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"), the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before commit f70029bbaacb, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make (N_MEMORY == N_NORMAL_MEMORY) be true. After commit f70029bbaacb, N_MEMORY doesn't have any chance to be equal to N_NORMAL_MEMORY. So the conditional check in paging_init() doesn't make sense any more. Let's remove it.
Signed-off-by Baoquan He <[email protected]>

The change looks good. While I have one question, we set default value for N_HIGH_MEMORY. Why we don't clear this too?

Reviewed-by Wei Yang <[email protected]>

Quoted 24 lines

---
v1->v2:
Update patch log to make the description clearer per Michal's suggestion.

arch/x86/mm/init_64.c | 3 +--

1 file changed, 1 insertion(+), 2 deletions(-)

arch/x86/mm/init_64.c +1 -2

index abbdecb75fad..0a14711d3a93 100644
@@ -818,8 +818,7 @@ void __init paging_init(void)
 	 *	 will not set it back.
 	 */
 	node_clear_state(0, N_MEMORY);
-	if (N_MEMORY != N_NORMAL_MEMORY)
-		node_clear_state(0, N_NORMAL_MEMORY);
+	node_clear_state(0, N_NORMAL_MEMORY);
 
 	zone_sizes_init();
 }

Signature · 1 line

2.17.2

Signature · 2 lines

Wei Yang
Help you, Help me

Baoquan He

author

2020-03-15 12:49 UTC #3 lore raw

Quoted 8 lines · Wei Yang

Quoted 7 lines · Baoquan He
In commit f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"), the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before commit f70029bbaacb, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make (N_MEMORY == N_NORMAL_MEMORY) be true. After commit f70029bbaacb, N_MEMORY doesn't have any chance to be equal to N_NORMAL_MEMORY. So the conditional check in paging_init() doesn't make sense any more. Let's remove it.

Quoted 4 lines

Quoted 1 line
Signed-off-by Baoquan He <[email protected]>
The change looks good. While I have one question, we set default value for N_HIGH_MEMORY. Why we don't clear this too?

This is for x86_64 only, there's no node_state for N_HIGH_MEMORY.

Quoted 32 lines

Reviewed-by Wei Yang <[email protected]>
Quoted 24 lines
---
v1->v2:
Update patch log to make the description clearer per Michal's suggestion.
arch/x86/mm/init_64.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
arch/x86/mm/init_64.c +1 -2
index abbdecb75fad..0a14711d3a93 100644
@@ -818,8 +818,7 @@ void __init paging_init(void)
 	 *	 will not set it back.
 	 */
 	node_clear_state(0, N_MEMORY);
-	if (N_MEMORY != N_NORMAL_MEMORY)
-		node_clear_state(0, N_NORMAL_MEMORY);
+	node_clear_state(0, N_NORMAL_MEMORY);
 
 	zone_sizes_init();
 }
Signature · 1 line
2.17.2
Signature · 2 lines
Wei Yang
Help you, Help me

Wei Yang

2020-03-15 21:57 UTC #4 lore raw

Quoted 9 lines · Baoquan He

Quoted 8 lines · Wei Yang
Quoted 7 lines · Baoquan He
In commit f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE"), the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before commit f70029bbaacb, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make (N_MEMORY == N_NORMAL_MEMORY) be true. After commit f70029bbaacb, N_MEMORY doesn't have any chance to be equal to N_NORMAL_MEMORY. So the conditional check in paging_init() doesn't make sense any more. Let's remove it.

Quoted 7 lines

Quoted 4 lines
Quoted 1 line
Signed-off-by Baoquan He <[email protected]>
The change looks good. While I have one question, we set default value for N_HIGH_MEMORY. Why we don't clear this too?
This is for x86_64 only, there's no node_state for N_HIGH_MEMORY.

Thanks, I see it in arch/x86/Kconfig.

Signature · 2 lines

Wei Yang
Help you, Help me

tip-bot2 for Baoquan He

merge bot Applied

2020-03-17 18:21 UTC #5 lore raw

[tip: x86/mm] x86/mm: Remove the now redundant N_MEMORY check

In reply to Baoquan He

The following commit has been merged into the x86/mm branch of tip:

Commit-ID:     aa61ee7b9ee3cb84c0d3a842b0d17937bf024c46
Gitweb:        https://git.kernel.org/tip/aa61ee7b9ee3cb84c0d3a842b0d17937bf024c46
Author:        Baoquan He <[email protected]>
AuthorDate:    Wed, 11 Mar 2020 09:18:23 +08:00
Committer:     Borislav Petkov <[email protected]>
CommitterDate: Tue, 17 Mar 2020 19:12:39 +01:00

x86/mm: Remove the now redundant N_MEMORY check

In commit

f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE")

the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make (N_MEMORY == N_NORMAL_MEMORY) be true.

After that commit, N_MEMORY cannot be equal to N_NORMAL_MEMORY. So the conditional check in paging_init() is not needed anymore, remove it.

[ bp: Massage. ]

Signed-off-by Baoquan He <[email protected]>

Signed-off-by Borislav Petkov <[email protected]>

Reviewed-by Wei Yang <[email protected]>

Acked-by Michal Hocko <[email protected]>

Link https://lkml.kernel.org/r/[email protected] open here

---
 arch/x86/mm/init_64.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

arch/x86/mm/init_64.c +1 -2

index abbdecb..0a14711 100644
@@ -818,8 +818,7 @@ void __init paging_init(void)
 	 *	 will not set it back.
 	 */
 	node_clear_state(0, N_MEMORY);
-	if (N_MEMORY != N_NORMAL_MEMORY)
-		node_clear_state(0, N_NORMAL_MEMORY);
+	node_clear_state(0, N_NORMAL_MEMORY);
 
 	zone_sizes_init();
 }

Baoquan He

author

2020-03-18 02:49 UTC #6 lore raw

Re: [tip: x86/mm] x86/mm: Remove the now redundant N_MEMORY check

Hi,

Quoted 8 lines · On 03/17/20 at 06:20pm, tip-bot2 for Baoquan He wrote:

The following commit has been merged into the x86/mm branch of tip:

Commit-ID:     aa61ee7b9ee3cb84c0d3a842b0d17937bf024c46
Gitweb:        https://git.kernel.org/tip/aa61ee7b9ee3cb84c0d3a842b0d17937bf024c46
Author:        Baoquan He <[email protected]>
AuthorDate:    Wed, 11 Mar 2020 09:18:23 +08:00
Committer:     Borislav Petkov <[email protected]>
CommitterDate: Tue, 17 Mar 2020 19:12:39 +01:00

Just a soft reminder, I also got a notice from Andrew that this was picked into his -mm tree before. Maybe one can be dropped to avoid conflict when sending to Linus.

Thanks for taking care of this.

Quoted 40 lines

x86/mm: Remove the now redundant N_MEMORY check
In commit
f70029bbaacb ("mm, memory_hotplug: drop CONFIG_MOVABLE_NODE")
the dependency on CONFIG_MOVABLE_NODE was removed for N_MEMORY. Before, CONFIG_HIGHMEM && !CONFIG_MOVABLE_NODE could make (N_MEMORY == N_NORMAL_MEMORY) be true.
After that commit, N_MEMORY cannot be equal to N_NORMAL_MEMORY. So the conditional check in paging_init() is not needed anymore, remove it.
[ bp: Massage. ]
Signed-off-by Baoquan He <[email protected]>
Signed-off-by Borislav Petkov <[email protected]>
Reviewed-by Wei Yang <[email protected]>
Acked-by Michal Hocko <[email protected]>
Link https://lkml.kernel.org/r/[email protected] open here
---
 arch/x86/mm/init_64.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
arch/x86/mm/init_64.c +1 -2
index abbdecb..0a14711 100644
@@ -818,8 +818,7 @@ void __init paging_init(void)
 	 *	 will not set it back.
 	 */
 	node_clear_state(0, N_MEMORY);
-	if (N_MEMORY != N_NORMAL_MEMORY)
-		node_clear_state(0, N_NORMAL_MEMORY);
+	node_clear_state(0, N_NORMAL_MEMORY);
 
 	zone_sizes_init();
 }