From: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Date: Fri, 25 Feb 2022 19:33:40 +0000 (-0600)
Subject: x86/mce: Avoid unnecessary padding in struct mce_bank
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9f1b19b977ee3cbd3fe9135ff63dbf221eac1d6a;p=linux.git

x86/mce: Avoid unnecessary padding in struct mce_bank

Convert struct mce_bank member "init" from bool to a bitfield to get rid
of unnecessary padding.

$ pahole -C mce_bank arch/x86/kernel/cpu/mce/core.o

before:

  /* size: 16, cachelines: 1, members: 2 */
  /* padding: 7 */
  /* last cacheline: 16 bytes */

after:

  /* size: 16, cachelines: 1, members: 3 */
  /* last cacheline: 16 bytes */

No functional changes.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220225193342.215780-2-Smita.KoralahalliChannabasappa@amd.com
---

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 981496e6bc0e4..d775fcd74e98d 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -69,7 +69,9 @@ DEFINE_PER_CPU_READ_MOSTLY(unsigned int, mce_num_banks);
 
 struct mce_bank {
 	u64			ctl;			/* subevents to enable */
-	bool			init;			/* initialise bank? */
+
+	__u64 init			: 1,		/* initialise bank? */
+	      __reserved_1		: 63;
 };
 static DEFINE_PER_CPU_READ_MOSTLY(struct mce_bank[MAX_NR_BANKS], mce_banks_array);