From nobody Thu Dec 18 00:49:51 2025 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (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 435CF4AEE2 for ; Fri, 21 Feb 2025 00:54:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=96.67.55.147 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740099255; cv=none; b=joQref5KlKymzklzAQAP11pwDFvO+tvTUH9BlRNOJC4KZDy7NEzOoPHdiulC280pbXVXDl8L98ij68BlL6krl96Ap/9dt7SUTl25qtqxdqrSJWyH3sidwqVPguA1f4shltL6u53t3B8zW92v3pfxkKRMXoPIQmH3EaV/LIZ/DK4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740099255; c=relaxed/simple; bh=qPmUBuFn1z5hB6hD+Oz8xdMKFiytnUh74nGHtli1uyw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tQVm9Zy9Qt66TxIrVWdMYyUa/OF3oZWHhgdiYBSpwfSy7Cdvh6t7nzhqFCa1eOyPD83K+jJzswGtOpS6mYjtwwD3khyC39vN/yMVtfrPR8u9UgRVIWkWEeBF2qQt/PkxwG8biaEqv+Z4WENbQlWY4HB5DvMQgUZXRsqNPuAF+Lo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com; spf=pass smtp.mailfrom=shelob.surriel.com; arc=none smtp.client-ip=96.67.55.147 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=shelob.surriel.com Received: from fangorn.home.surriel.com ([10.0.13.7]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.97.1) (envelope-from ) id 1tlHIZ-000000003Qf-0nqE; Thu, 20 Feb 2025 19:53:47 -0500 From: Rik van Riel To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, bp@alien8.de, peterz@infradead.org, dave.hansen@linux.intel.com, zhengqi.arch@bytedance.com, nadav.amit@gmail.com, thomas.lendacky@amd.com, kernel-team@meta.com, linux-mm@kvack.org, akpm@linux-foundation.org, jackmanb@google.com, jannh@google.com, mhklinux@outlook.com, andrew.cooper3@citrix.com, Manali.Shukla@amd.com, Rik van Riel , Dave Hansen Subject: [PATCH v12 03/16] x86/mm: consolidate full flush threshold decision Date: Thu, 20 Feb 2025 19:53:02 -0500 Message-ID: <20250221005345.2156760-4-riel@surriel.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250221005345.2156760-1-riel@surriel.com> References: <20250221005345.2156760-1-riel@surriel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: riel@surriel.com Content-Type: text/plain; charset="utf-8" Reduce code duplication by consolidating the decision point for whether to do individual invalidations or a full flush inside get_flush_tlb_info. Signed-off-by: Rik van Riel Suggested-by: Dave Hansen Tested-by: Michael Kelley Acked-by: Dave Hansen --- arch/x86/mm/tlb.c | 41 +++++++++++++++++++---------------------- 1 file changed, 19 insertions(+), 22 deletions(-) diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index ffc25b348041..dbcb5c968ff9 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -1000,6 +1000,15 @@ static struct flush_tlb_info *get_flush_tlb_info(str= uct mm_struct *mm, BUG_ON(this_cpu_inc_return(flush_tlb_info_idx) !=3D 1); #endif =20 + /* + * If the number of flushes is so large that a full flush + * would be faster, do a full flush. + */ + if ((end - start) >> stride_shift > tlb_single_page_flush_ceiling) { + start =3D 0; + end =3D TLB_FLUSH_ALL; + } + info->start =3D start; info->end =3D end; info->mm =3D mm; @@ -1026,17 +1035,8 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsign= ed long start, bool freed_tables) { struct flush_tlb_info *info; + int cpu =3D get_cpu(); u64 new_tlb_gen; - int cpu; - - cpu =3D get_cpu(); - - /* Should we flush just the requested range? */ - if ((end =3D=3D TLB_FLUSH_ALL) || - ((end - start) >> stride_shift) > tlb_single_page_flush_ceiling) { - start =3D 0; - end =3D TLB_FLUSH_ALL; - } =20 /* This is also a barrier that synchronizes with switch_mm(). */ new_tlb_gen =3D inc_mm_tlb_gen(mm); @@ -1089,22 +1089,19 @@ static void do_kernel_range_flush(void *info) =20 void flush_tlb_kernel_range(unsigned long start, unsigned long end) { - /* Balance as user space task's flush, a bit conservative */ - if (end =3D=3D TLB_FLUSH_ALL || - (end - start) > tlb_single_page_flush_ceiling << PAGE_SHIFT) { - on_each_cpu(do_flush_tlb_all, NULL, 1); - } else { - struct flush_tlb_info *info; + struct flush_tlb_info *info; + + guard(preempt)(); =20 - preempt_disable(); - info =3D get_flush_tlb_info(NULL, start, end, 0, false, - TLB_GENERATION_INVALID); + info =3D get_flush_tlb_info(NULL, start, end, PAGE_SHIFT, false, + TLB_GENERATION_INVALID); =20 + if (info->end =3D=3D TLB_FLUSH_ALL) + on_each_cpu(do_flush_tlb_all, NULL, 1); + else on_each_cpu(do_kernel_range_flush, info, 1); =20 - put_flush_tlb_info(); - preempt_enable(); - } + put_flush_tlb_info(); } =20 /* --=20 2.47.1