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authorAnna-Maria Behnsen <anna-maria@linutronix.de>2024-07-01 16:47:55 +0200
committerThomas Gleixner <tglx@linutronix.de>2024-07-03 21:27:03 +0200
commitd00106bbdfa82732c23cba44491c38f8c410d865 (patch)
tree099e87b386a66fda527c50c0db83e1e2ca015311
parentf48955e038eaf43812c3701079c7371abe0315a4 (diff)
vdso: Add comment about reason for vdso struct ordering
struct vdso_data is optimized for fast access to the often required struct members. The optimization is not documented in the struct description but it should be kept in mind, when working with the vdso_data struct. Add a comment to the struct description. Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20240701-vdso-cleanup-v1-2-36eb64e7ece2@linutronix.de
-rw-r--r--include/vdso/datapage.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index d04d394db064..7647e0946f50 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -77,6 +77,10 @@ struct vdso_timestamp {
* vdso_data will be accessed by 64 bit and compat code at the same time
* so we should be careful before modifying this structure.
*
+ * The ordering of the struct members is optimized to have fast access to the
+ * often required struct members which are related to CLOCK_REALTIME and
+ * CLOCK_MONOTONIC. This information is stored in the first cache lines.
+ *
* @basetime is used to store the base time for the system wide time getter
* VVAR page.
*