linux-kernel - [tip: ras/core] x86/mce: Avoid unnecessary padding in struct mce

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Message-ID: <164919217791.389.16926889046664512675.tip-bot2@tip-bot2>
Date:   Tue, 05 Apr 2022 20:56:17 -0000
From:   "tip-bot2 for Smita Koralahalli" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>,
        Borislav Petkov <bp@...e.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: ras/core] x86/mce: Avoid unnecessary padding in struct mce_bank

The following commit has been merged into the ras/core branch of tip:

Commit-ID:     9f1b19b977ee3cbd3fe9135ff63dbf221eac1d6a
Gitweb:        https://git.kernel.org/tip/9f1b19b977ee3cbd3fe9135ff63dbf221eac1d6a
Author:        Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
AuthorDate:    Fri, 25 Feb 2022 13:33:40 -06:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Tue, 05 Apr 2022 21:23:34 +02:00

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@....com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lore.kernel.org/r/20220225193342.215780-2-Smita.KoralahalliChannabasappa@amd.com
---
 arch/x86/kernel/cpu/mce/core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 981496e..d775fcd 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);