From patchwork Thu Jun 30 09:46:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Haibo Li X-Patchwork-Id: 12901591 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4550EC433EF for ; Thu, 30 Jun 2022 10:18:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=eYkJoa/0UJo+7yqtZrgFOU7Q2onaxfGGKww/YiP4fKM=; b=oLaz818rgo/S6QPSbbPcbGN9ye YCIpbF54gzzVMod579UidO3Okm6NkJTKy+dKiyziuhsi1AHiMlC/2Z4XkfhrQQYUkNVCLWMzVI6Uq MEKDipBKl/eXtJgDaRjkYNu5okMan+EtXjaH75Y+y8G0cbQRLiQmFnQ6cNNa9EXZvapXnT4/lWTxU GYXytuM9X/Qn3Jz3fM9k5Braid/2UXKO3BUnILOI3ZLarKH4hMq/YSZlpKSnGEH+BhGqx5ykduZFT AqxKgXD39RJxwmuj6TbPpTOoRdfQIL5a94i16rPqL9IJ3q0MCV9dSXc328lIa0vbDqxHvTtU1h9HK VfPnwTnA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o6rFE-00GVVf-Az; Thu, 30 Jun 2022 10:17:56 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o6rFB-00GVTh-Hp; Thu, 30 Jun 2022 10:17:54 +0000 X-UUID: 0f3ea2dce78049168a18f854e41e2e96-20220630 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.7,REQID:6880349b-6e07-44f6-a9ec-3c1b560981b3,OB:0,LO B:0,IP:0,URL:5,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,RULE:Release_Ham,ACTI ON:release,TS:5 X-CID-META: VersionHash:87442a2,CLOUDID:de6b3186-57f0-47ca-ba27-fe8c57fbf305,C OID:IGNORED,Recheck:0,SF:nil,TC:nil,Content:0,EDM:-3,IP:nil,URL:1,File:nil ,QS:nil,BEC:nil,COL:0 X-UUID: 0f3ea2dce78049168a18f854e41e2e96-20220630 Received: from mtkmbs11n1.mediatek.inc [(172.21.101.185)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 355211776; Thu, 30 Jun 2022 03:17:44 -0700 Received: from mtkmbs11n2.mediatek.inc (172.21.101.187) by mtkmbs11n1.mediatek.inc (172.21.101.185) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.792.3; Thu, 30 Jun 2022 17:47:06 +0800 Received: from mszsdtcf10.gcn.mediatek.inc (10.16.4.60) by mtkmbs11n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.792.3 via Frontend Transport; Thu, 30 Jun 2022 17:47:05 +0800 From: Haibo Li To: Sami Tolvanen CC: , Kees Cook , Nathan Chancellor , Nick Desaulniers , Matthias Brugger , Peter Zijlstra , Masami Hiramatsu , Christophe Leroy , =?utf-8?q?Andr=C3=A9_Almeid?= =?utf-8?q?a?= , Luis Chamberlain , Juergen Gross , Haibo Li , Tiezhu Yang , Aaron Tomlin , Dmitry Torokhov , , , , , Lecopzer Chen Subject: [PATCH 2/2] ANDROID: cfi: free old cfi shadow asynchronously Date: Thu, 30 Jun 2022 17:46:46 +0800 Message-ID: <20220630094646.91837-3-haibo.li@mediatek.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220630094646.91837-1-haibo.li@mediatek.com> References: <20220630094646.91837-1-haibo.li@mediatek.com> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220630_031753_622675_8624FBE9 X-CRM114-Status: GOOD ( 13.83 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org Currenly, it uses synchronize_rcu() to wait old rcu reader to go away in update_shadow.In embedded platform like ARM CA7X, load_module blocks 40~50ms in update_shadow. When there are more than one hundred kernel modules, it blocks several seconds. To accelerate load_module,change synchronize_rcu to call_rcu. Signed-off-by: Haibo Li Signed-off-by: Lecopzer Chen --- kernel/cfi.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/cfi.c b/kernel/cfi.c index 456771c8e454..a4836d59ca27 100644 --- a/kernel/cfi.c +++ b/kernel/cfi.c @@ -43,6 +43,8 @@ typedef u16 shadow_t; struct cfi_shadow { /* Page index for the beginning of the shadow */ unsigned long base; + /* rcu to free old cfi_shadow asynchronously */ + struct rcu_head rcu; /* An array of __cfi_check locations (as indices to the shadow) */ shadow_t shadow[1]; } __packed; @@ -182,6 +184,13 @@ static void remove_module_from_shadow(struct cfi_shadow *s, struct module *mod, } } +static void _cfi_shadow_free_rcu(struct rcu_head *rcu) +{ + struct cfi_shadow *old = container_of(rcu, struct cfi_shadow, rcu); + + vfree(old); +} + typedef void (*update_shadow_fn)(struct cfi_shadow *, struct module *, unsigned long min_addr, unsigned long max_addr); @@ -211,11 +220,10 @@ static void update_shadow(struct module *mod, unsigned long base_addr, rcu_assign_pointer(cfi_shadow, next); mutex_unlock(&shadow_update_lock); - synchronize_rcu(); if (prev) { set_memory_rw((unsigned long)prev, SHADOW_PAGES); - vfree(prev); + call_rcu(&prev->rcu, _cfi_shadow_free_rcu); } }