* [PATCH v2] x86/apic: Inline __x2apic_send_IPI_dest()
@ 2025-12-23 5:20 Eric Dumazet
2026-01-20 9:16 ` Eric Dumazet
2026-01-26 15:41 ` [tip: x86/apic] " tip-bot2 for Eric Dumazet
0 siblings, 2 replies; 3+ messages in thread
From: Eric Dumazet @ 2025-12-23 5:20 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H . Peter Anvin
Cc: linux-kernel, Eric Dumazet, Eric Dumazet
Avoid one call/ret in networking RPS/RFS fast path, with no space cost.
scripts/bloat-o-meter -t vmlinux.before vmlinux.after
add/remove: 0/2 grow/shrink: 2/0 up/down: 96/-97 (-1)
Function old new delta
x2apic_send_IPI 146 198 +52
__x2apic_send_IPI_mask 326 370 +44
__pfx___x2apic_send_IPI_dest 16 - -16
__x2apic_send_IPI_dest 81 - -81
Total: Before=20861234, After=20861233, chg -0.00%
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
v2: added CONFIG_X86_X2APIC dependency (kernel test robot), updated bloat-o-meter
v1: https://lore.kernel.org/lkml/CANn89iJ4r5hrqE=Lj16XVNFM7iZ+XB+JsXU8gE5ryeuG6kf1Sg@mail.gmail.com/T/#mc7288459ec504831a9888cb0e5c4dbdae253f263
arch/x86/kernel/apic/local.h | 10 +++++++++-
arch/x86/kernel/apic/x2apic_phys.c | 6 ------
2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/apic/local.h b/arch/x86/kernel/apic/local.h
index bdcf609eb283..0e5dd6772d6a 100644
--- a/arch/x86/kernel/apic/local.h
+++ b/arch/x86/kernel/apic/local.h
@@ -14,7 +14,6 @@
#include <asm/apic.h>
/* X2APIC */
-void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);
u32 x2apic_get_apic_id(u32 id);
void x2apic_send_IPI_all(int vector);
@@ -42,6 +41,15 @@ static inline unsigned int __prepare_ICR(unsigned int shortcut, int vector,
return icr;
}
+#ifdef CONFIG_X86_X2APIC
+static inline void __x2apic_send_IPI_dest(unsigned int apicid, int vector,
+ unsigned int dest)
+{
+ unsigned long cfg = __prepare_ICR(0, vector, dest);
+ native_x2apic_icr_write(cfg, apicid);
+}
+#endif
+
void default_init_apic_ldr(void);
void apic_mem_wait_icr_idle(void);
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index 12d4c35547a6..10f79026e8e3 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -107,12 +107,6 @@ void x2apic_send_IPI_self(int vector)
apic_write(APIC_SELF_IPI, vector);
}
-void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest)
-{
- unsigned long cfg = __prepare_ICR(0, vector, dest);
- native_x2apic_icr_write(cfg, apicid);
-}
-
static int x2apic_phys_probe(void)
{
if (!x2apic_mode)
--
2.52.0.351.gbe84eed79e-goog
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] x86/apic: Inline __x2apic_send_IPI_dest()
2025-12-23 5:20 [PATCH v2] x86/apic: Inline __x2apic_send_IPI_dest() Eric Dumazet
@ 2026-01-20 9:16 ` Eric Dumazet
2026-01-26 15:41 ` [tip: x86/apic] " tip-bot2 for Eric Dumazet
1 sibling, 0 replies; 3+ messages in thread
From: Eric Dumazet @ 2026-01-20 9:16 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H . Peter Anvin
Cc: linux-kernel, Eric Dumazet
On Tue, Dec 23, 2025 at 6:20 AM Eric Dumazet <edumazet@google.com> wrote:
>
> Avoid one call/ret in networking RPS/RFS fast path, with no space cost.
>
> scripts/bloat-o-meter -t vmlinux.before vmlinux.after
> add/remove: 0/2 grow/shrink: 2/0 up/down: 96/-97 (-1)
> Function old new delta
> x2apic_send_IPI 146 198 +52
> __x2apic_send_IPI_mask 326 370 +44
> __pfx___x2apic_send_IPI_dest 16 - -16
> __x2apic_send_IPI_dest 81 - -81
> Total: Before=20861234, After=20861233, chg -0.00%
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
> v2: added CONFIG_X86_X2APIC dependency (kernel test robot), updated bloat-o-meter
> v1: https://lore.kernel.org/lkml/CANn89iJ4r5hrqE=Lj16XVNFM7iZ+XB+JsXU8gE5ryeuG6kf1Sg@mail.gmail.com/T/#mc7288459ec504831a9888cb0e5c4dbdae253f263
>
> arch/x86/kernel/apic/local.h | 10 +++++++++-
> arch/x86/kernel/apic/x2apic_phys.c | 6 ------
> 2 files changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kernel/apic/local.h b/arch/x86/kernel/apic/local.h
> index bdcf609eb283..0e5dd6772d6a 100644
> --- a/arch/x86/kernel/apic/local.h
> +++ b/arch/x86/kernel/apic/local.h
> @@ -14,7 +14,6 @@
> #include <asm/apic.h>
>
> /* X2APIC */
> -void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);
> u32 x2apic_get_apic_id(u32 id);
>
> void x2apic_send_IPI_all(int vector);
> @@ -42,6 +41,15 @@ static inline unsigned int __prepare_ICR(unsigned int shortcut, int vector,
> return icr;
> }
>
> +#ifdef CONFIG_X86_X2APIC
> +static inline void __x2apic_send_IPI_dest(unsigned int apicid, int vector,
> + unsigned int dest)
> +{
> + unsigned long cfg = __prepare_ICR(0, vector, dest);
> + native_x2apic_icr_write(cfg, apicid);
> +}
> +#endif
> +
> void default_init_apic_ldr(void);
>
> void apic_mem_wait_icr_idle(void);
> diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
> index 12d4c35547a6..10f79026e8e3 100644
> --- a/arch/x86/kernel/apic/x2apic_phys.c
> +++ b/arch/x86/kernel/apic/x2apic_phys.c
> @@ -107,12 +107,6 @@ void x2apic_send_IPI_self(int vector)
> apic_write(APIC_SELF_IPI, vector);
> }
>
> -void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest)
> -{
> - unsigned long cfg = __prepare_ICR(0, vector, dest);
> - native_x2apic_icr_write(cfg, apicid);
> -}
> -
> static int x2apic_phys_probe(void)
> {
> if (!x2apic_mode)
> --
> 2.52.0.351.gbe84eed79e-goog
>
I do not think I received any feedback for this patch, should I resend it ?
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread* [tip: x86/apic] x86/apic: Inline __x2apic_send_IPI_dest()
2025-12-23 5:20 [PATCH v2] x86/apic: Inline __x2apic_send_IPI_dest() Eric Dumazet
2026-01-20 9:16 ` Eric Dumazet
@ 2026-01-26 15:41 ` tip-bot2 for Eric Dumazet
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot2 for Eric Dumazet @ 2026-01-26 15:41 UTC (permalink / raw)
To: linux-tip-commits; +Cc: Eric Dumazet, Thomas Gleixner, x86, linux-kernel
The following commit has been merged into the x86/apic branch of tip:
Commit-ID: 9bad74127f0ae8eeed2510fe381b064e08e6507e
Gitweb: https://git.kernel.org/tip/9bad74127f0ae8eeed2510fe381b064e08e6507e
Author: Eric Dumazet <edumazet@google.com>
AuthorDate: Tue, 23 Dec 2025 05:20:26
Committer: Thomas Gleixner <tglx@kernel.org>
CommitterDate: Mon, 26 Jan 2026 16:25:18 +01:00
x86/apic: Inline __x2apic_send_IPI_dest()
Avoid one call/ret in networking RPS/RFS fast path, with no space cost.
scripts/bloat-o-meter -t vmlinux.before vmlinux.after
add/remove: 0/2 grow/shrink: 2/0 up/down: 96/-97 (-1)
Function old new delta
x2apic_send_IPI 146 198 +52
__x2apic_send_IPI_mask 326 370 +44
__pfx___x2apic_send_IPI_dest 16 - -16
__x2apic_send_IPI_dest 81 - -81
Total: Before=20861234, After=20861233, chg -0.00%
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20251223052026.4141498-1-edumazet@google.com
---
arch/x86/kernel/apic/local.h | 10 +++++++++-
arch/x86/kernel/apic/x2apic_phys.c | 6 ------
2 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/apic/local.h b/arch/x86/kernel/apic/local.h
index bdcf609..998efd4 100644
--- a/arch/x86/kernel/apic/local.h
+++ b/arch/x86/kernel/apic/local.h
@@ -14,7 +14,6 @@
#include <asm/apic.h>
/* X2APIC */
-void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);
u32 x2apic_get_apic_id(u32 id);
void x2apic_send_IPI_all(int vector);
@@ -42,6 +41,15 @@ static inline unsigned int __prepare_ICR(unsigned int shortcut, int vector,
return icr;
}
+#ifdef CONFIG_X86_X2APIC
+static inline void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest)
+{
+ unsigned long cfg = __prepare_ICR(0, vector, dest);
+
+ native_x2apic_icr_write(cfg, apicid);
+}
+#endif
+
void default_init_apic_ldr(void);
void apic_mem_wait_icr_idle(void);
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index 12d4c35..10f7902 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -107,12 +107,6 @@ void x2apic_send_IPI_self(int vector)
apic_write(APIC_SELF_IPI, vector);
}
-void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest)
-{
- unsigned long cfg = __prepare_ICR(0, vector, dest);
- native_x2apic_icr_write(cfg, apicid);
-}
-
static int x2apic_phys_probe(void)
{
if (!x2apic_mode)
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-12-23 5:20 [PATCH v2] x86/apic: Inline __x2apic_send_IPI_dest() Eric Dumazet
2026-01-20 9:16 ` Eric Dumazet
2026-01-26 15:41 ` [tip: x86/apic] " tip-bot2 for Eric Dumazet
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