[PATCH 18/19] vdso: Move arch related data before basetime
From: Thomas Weißschuh <hidden>
Date: 2025-03-03 11:11:19
Also in:
linux-arch, linux-arm-kernel, linux-s390, lkml
Subsystem:
generic vdso library, the rest · Maintainers:
Andy Lutomirski, Thomas Gleixner, Vincenzo Frascino, Linus Torvalds
From: Anna-Maria Behnsen <anna-maria@linutronix.de> Architecture related vdso data is required in fastpath when acquiring CLOCK_MONOTONIC or CLOCK_REALTIME. At the moment, this information is located at the end of the vdso_time_data structure. The whole structure has to be loaded into cache to be able to access this information. To minimize the number of required cachelines, the architecture specific vdso data struct is moved right before the basetime (basetime information is required anyway). This change does not have an impact on architectures with CONFIG_ARCH_HAS_VDSO_DATA=n. All other architectures could spare reading unnecessary cachelines. Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> Signed-off-by: Nam Cao <redacted> Signed-off-by: Thomas Weißschuh <redacted> --- include/vdso/datapage.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index 1df22e8bb9b31153546b72b1e8b8c8aeaed7d9e3..bcd19c223783be7c22f90120330e7dddd0496f1a 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h@@ -70,6 +70,8 @@ struct vdso_timestamp { /** * struct vdso_time_data - vdso datapage representation + * @arch_data: architecture specific data (optional, defaults + * to an empty struct) * @seq: timebase sequence counter * @clock_mode: clock mode * @cycle_last: timebase at clocksource init
@@ -83,8 +85,6 @@ struct vdso_timestamp { * @tz_dsttime: type of DST correction * @hrtimer_res: hrtimer resolution * @__unused: unused - * @arch_data: architecture specific data (optional, defaults - * to an empty struct) * * vdso_time_data will be accessed by 64 bit and compat code at the same time * so we should be careful before modifying this structure.
@@ -105,6 +105,8 @@ struct vdso_timestamp { * offset must be zero. */ struct vdso_time_data { + struct arch_vdso_time_data arch_data; + u32 seq; s32 clock_mode;
@@ -125,8 +127,6 @@ struct vdso_time_data { s32 tz_dsttime; u32 hrtimer_res; u32 __unused; - - struct arch_vdso_time_data arch_data; } ____cacheline_aligned; #define vdso_clock vdso_time_data
--
2.48.1