From patchwork Sun Nov 24 14:07:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Rapoport X-Patchwork-Id: 13884139 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 573F818787A; Sun, 24 Nov 2024 14:07:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732457238; cv=none; b=QeQiUp4K7Ob+1xnsVg8mxnnPgr77Nqwyv3ODztg7qgey3OQVEQj1JGMB/CP+AUsYEbRZXnwRj33vXc7qf3t12DBvZA0O2TjNVnlWDNhZxNgm0iygYS+CofMiChNw7wm6OA+tQsQJLLpGGLukOtAQY+mlGipOkzTf05v7Ms+9Gj0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732457238; c=relaxed/simple; bh=hEsIg8aAsdwalXsLOpm5dcCFEtD8GwTLrcsPwRmzB3w=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=IrBNoob4YQm5u4z47PFvfpDDNYmDd5vRnbg5g8Ys4drKH56+oNYptvl5r6goa2ypMYmPH/SKcdhbGqJ/jvLCivX20OaYArHyHrASiK7HDd831e49PloeCsH5YHdPp6Bq1hgieHthXh5P8JQ2jC/gg1S8gSL1XEm+5Q4u+Rm8HdY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sKlqqnRx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sKlqqnRx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2987C4CED1; Sun, 24 Nov 2024 14:07:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732457237; bh=hEsIg8aAsdwalXsLOpm5dcCFEtD8GwTLrcsPwRmzB3w=; h=From:To:Cc:Subject:Date:From; b=sKlqqnRxgFPibjFENI175GGmn+Zw27RmsXUKJ2BZz72gXCHNh3r6bk+gJmmFqCzrj yg2/k2MQ9Bbw59Y3/cETbVRjZSYZtVXfSW3YZNYkiNMg3lm7baiEcKzA9OUbZe2nc6 d1MpmMk5otREdlwFkAPfcPw1APEJelOGIyYckk65SLSJJVIHjjWcY5B7B0VLn1Ypzp fc5lT2Qr+8vY95VTZ/gsp6ynDZeSJPVcbfl9BUCkcSJKtYaehsKeH0hBZc1BoFHcxF Sif529F6ln5SYpdgnqhr50/2ABF7y1AvOhGIfEwerG93gzp1LmhsSHfyszTD2VnRoN NZrb/MlBd0VYQ== From: Mike Rapoport To: Andrew Morton Cc: Borislav Petkov , Dave Hansen , Ingo Molnar , Masami Hiramatsu , Mike Rapoport , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org Subject: [PATCH] x86/ftrace: fix boot time slowdown Date: Sun, 24 Nov 2024 16:07:05 +0200 Message-ID: <20241124140705.2883-1-rppt@kernel.org> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: "Mike Rapoport (Microsoft)" Steven Rostedt reported slowdown by over 30ms caused by commit 9bfc4824fd48 ("x86/module: prepare module loading for ROX allocations of text") Before: # cat /sys/kernel/tracing/dyn_ftrace_total_info 57695 pages:231 groups: 9 ftrace boot update time = 14733459 (ns) ftrace module total update time = 449016 (ns) After: # cat /sys/kernel/tracing/dyn_ftrace_total_info 57708 pages:231 groups: 9 ftrace boot update time = 47195374 (ns) ftrace module total update time = 592080 (ns) The slowdown happened because initial patching of kernel code for ftrace was switched from text_poke_early() to text_poke() to accommodate ftrace updates of module text allocated as ROX. Restore the use of text_poke_early() for boot time patching of the kernel code. Reported-by: Steven Rostedt Closes: https://lore.kernel.org/all/20241118132501.4eddb46c@gandalf.local.home Fixes: 9bfc4824fd48 ("x86/module: prepare module loading for ROX allocations of text") Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Masami Hiramatsu (Google) --- arch/x86/kernel/ftrace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) base-commit: 9f16d5e6f220661f73b36a4be1b21575651d8833 diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 4dd0ad6c94d6..9e50288abbaa 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -111,7 +111,7 @@ static int ftrace_verify_code(unsigned long ip, const char *old_code) */ static int __ref ftrace_modify_code_direct(unsigned long ip, const char *old_code, - const char *new_code) + const char *new_code, struct module *mod) { int ret = ftrace_verify_code(ip, old_code); if (ret) @@ -120,6 +120,8 @@ ftrace_modify_code_direct(unsigned long ip, const char *old_code, /* replace the text with the new text */ if (ftrace_poke_late) { text_poke_queue((void *)ip, new_code, MCOUNT_INSN_SIZE, NULL); + } else if (!mod) { + text_poke_early((void *)ip, new_code, MCOUNT_INSN_SIZE); } else { mutex_lock(&text_mutex); text_poke((void *)ip, new_code, MCOUNT_INSN_SIZE); @@ -145,7 +147,7 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long ad * just modify the code directly. */ if (addr == MCOUNT_ADDR) - return ftrace_modify_code_direct(ip, old, new); + return ftrace_modify_code_direct(ip, old, new, mod); /* * x86 overrides ftrace_replace_code -- this function will never be used @@ -164,7 +166,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) new = ftrace_call_replace(ip, addr); /* Should only be called when module is loaded */ - return ftrace_modify_code_direct(rec->ip, old, new); + return ftrace_modify_code_direct(rec->ip, old, new, NULL); } /*