From patchwork Fri Feb 11 08:51:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1591525 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4Jw6my4P37z9s0r for ; Fri, 11 Feb 2022 19:52:02 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Jw6my1MVWz3cCT for ; 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Fri, 11 Feb 2022 09:51:49 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 3CD078B77D; Fri, 11 Feb 2022 09:51:49 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id j-f1FxCK2_RO; Fri, 11 Feb 2022 09:51:49 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [192.168.6.91]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 0724A8B764; Fri, 11 Feb 2022 09:51:48 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 21B8peER936906 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Fri, 11 Feb 2022 09:51:40 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 21B8pdwR936905; Fri, 11 Feb 2022 09:51:39 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Subject: [PATCH] powerpc/bitops: Force inlining of fls() Date: Fri, 11 Feb 2022 09:51:32 +0100 Message-Id: X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1644569488; l=1865; s=20211009; h=from:subject:message-id; bh=M/5xahDUgG0mQf2oI1XcOb4Sgn+k9YQrjuKrDZuQ4W4=; b=jKko6cLnkRwrZ2Sa2GEyicM3hSwPMV05extt276vgQtPZcvhlXQgURBJV55Meg1JOdACitoZtRkF zi8KiYFsDAUydLMeW5amIg+LVokcpphXKMDi7AjtezD5EvilvI6h X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Building a kernel with CONFIG_CC_OPTIMISE_FOR_SIZE leads to the following functions being copied several times in vmlinux: 31 times __ilog2_u32() 34 times fls() Disassembly follows: c00f476c : c00f476c: 7c 63 00 34 cntlzw r3,r3 c00f4770: 20 63 00 20 subfic r3,r3,32 c00f4774: 4e 80 00 20 blr c00f4778 <__ilog2_u32>: c00f4778: 94 21 ff f0 stwu r1,-16(r1) c00f477c: 7c 08 02 a6 mflr r0 c00f4780: 90 01 00 14 stw r0,20(r1) c00f4784: 4b ff ff e9 bl c00f476c c00f4788: 80 01 00 14 lwz r0,20(r1) c00f478c: 38 63 ff ff addi r3,r3,-1 c00f4790: 7c 08 03 a6 mtlr r0 c00f4794: 38 21 00 10 addi r1,r1,16 c00f4798: 4e 80 00 20 blr When forcing inlining of fls(), we get c0008b80 <__ilog2_u32>: c0008b80: 7c 63 00 34 cntlzw r3,r3 c0008b84: 20 63 00 1f subfic r3,r3,31 c0008b88: 4e 80 00 20 blr vmlinux size gets reduced by 1 kbyte with that change. Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/bitops.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/bitops.h b/arch/powerpc/include/asm/bitops.h index f18b1eac6b54..7df7fee774e5 100644 --- a/arch/powerpc/include/asm/bitops.h +++ b/arch/powerpc/include/asm/bitops.h @@ -288,7 +288,7 @@ static __always_inline void arch___clear_bit_unlock(int nr, volatile unsigned lo * fls: find last (most-significant) bit set. * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. */ -static inline int fls(unsigned int x) +static __always_inline int fls(unsigned int x) { int lz; @@ -306,7 +306,7 @@ static inline int fls(unsigned int x) * 32-bit fls calls. */ #ifdef CONFIG_PPC64 -static inline int fls64(__u64 x) +static __always_inline int fls64(__u64 x) { int lz;