From patchwork Wed Oct 10 19:19:33 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 10635127 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2C6AE69B1 for ; Wed, 10 Oct 2018 19:20:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1F8832AA2E for ; Wed, 10 Oct 2018 19:20:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 138482AA4B; Wed, 10 Oct 2018 19:20:41 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 55AE52AA2E for ; Wed, 10 Oct 2018 19:20:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727771AbeJKCnw (ORCPT ); Wed, 10 Oct 2018 22:43:52 -0400 Received: from mail.efficios.com ([167.114.142.138]:33240 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727874AbeJKCnv (ORCPT ); Wed, 10 Oct 2018 22:43:51 -0400 Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 139BF183C38; Wed, 10 Oct 2018 15:20:17 -0400 (EDT) Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id umG9iNsW-gsD; Wed, 10 Oct 2018 15:20:16 -0400 (EDT) Received: from localhost (ip6-localhost [IPv6:::1]) by mail.efficios.com (Postfix) with ESMTP id 84934183C2D; Wed, 10 Oct 2018 15:20:16 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 84934183C2D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1539199216; bh=/tkEB8pTPAKnqB+zmd5U6i3WoXW9DZMBZszErwJcPFc=; h=From:To:Date:Message-Id; b=rU4dL5OITQtZiaBux+bsRKkDNh7Urb2XrlTYNrYfjcmsmLaJt05qJXKMf7WJaICsy ZGcmiyYoAG4cM+/yLYvRWjzfLra+L7gPjjgF3Rmg8n/4wi0soSzipNCqCFgHb3+kRA wUK/I40QEjBo/nhEJl2OUXEwwfx9nAd64cHWV4htHFWTq9DYobpxEEksJ54KbbKBaV YOFcawd15OoQuYJCcHIDVE8aKHuLgbS0N4nOvbTFWCWUmQY66s9w/So6J12id7S2wX gJKsjfmPN6X6Cs0YBCnUweM2pGSh4fbA1ONT5xb9V/abMdVHDXa2sE0QnAby178Lql Uv8sR4c4B9Nbw== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([IPv6:::1]) by localhost (mail02.efficios.com [IPv6:::1]) (amavisd-new, port 10026) with ESMTP id xXh-aNnbzbiq; Wed, 10 Oct 2018 15:20:16 -0400 (EDT) Received: from thinkos.internal.efficios.com (192-222-157-41.qc.cable.ebox.net [192.222.157.41]) by mail.efficios.com (Postfix) with ESMTPSA id 94491183C22; Wed, 10 Oct 2018 15:20:15 -0400 (EDT) From: Mathieu Desnoyers To: Peter Zijlstra , "Paul E . McKenney" , Boqun Feng Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Thomas Gleixner , Andy Lutomirski , Dave Watson , Paul Turner , Andrew Morton , Russell King , Ingo Molnar , "H . Peter Anvin" , Andi Kleen , Chris Lameter , Ben Maurer , Steven Rostedt , Josh Triplett , Linus Torvalds , Catalin Marinas , Will Deacon , Michael Kerrisk , Joel Fernandes , Mathieu Desnoyers , Shuah Khan , linux-kselftest@vger.kernel.org Subject: [RFC PATCH for 4.21 13/16] cpu-opv/selftests: Provide percpu_op API Date: Wed, 10 Oct 2018 15:19:33 -0400 Message-Id: <20181010191936.7495-14-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20181010191936.7495-1-mathieu.desnoyers@efficios.com> References: <20181010191936.7495-1-mathieu.desnoyers@efficios.com> Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Introduce percpu-op.h API. It uses rseq internally as fast-path if invoked from the right CPU, else cpu_opv as slow-path if called from the wrong CPU or if rseq fails. This allows acting on per-cpu data from various CPUs transparently from user-space: cpu_opv will take care of migrating the thread to the requested CPU. Use-cases such as rebalancing memory across per-cpu memory pools, or migrating tasks for a user-space scheduler, are thus facilitated. This also handles debugger single-stepping. The use from userspace is, e.g. for a counter increment: int cpu, ret; cpu = percpu_current_cpu(); ret = percpu_addv(&data->c[cpu].count, 1, cpu); if (unlikely(ret)) { perror("percpu_addv"); return -1; } return 0; Signed-off-by: Mathieu Desnoyers CC: Shuah Khan CC: Russell King CC: Catalin Marinas CC: Will Deacon CC: Thomas Gleixner CC: Paul Turner CC: Peter Zijlstra CC: Andy Lutomirski CC: Andi Kleen CC: Dave Watson CC: Chris Lameter CC: Ingo Molnar CC: "H. Peter Anvin" CC: Ben Maurer CC: Steven Rostedt CC: "Paul E. McKenney" CC: Josh Triplett CC: Linus Torvalds CC: Andrew Morton CC: Boqun Feng CC: linux-kselftest@vger.kernel.org CC: linux-api@vger.kernel.org --- tools/testing/selftests/cpu-opv/percpu-op.h | 151 ++++++++++++++++++++++++++++ 1 file changed, 151 insertions(+) create mode 100644 tools/testing/selftests/cpu-opv/percpu-op.h diff --git a/tools/testing/selftests/cpu-opv/percpu-op.h b/tools/testing/selftests/cpu-opv/percpu-op.h new file mode 100644 index 000000000000..ffc64b268fd3 --- /dev/null +++ b/tools/testing/selftests/cpu-opv/percpu-op.h @@ -0,0 +1,151 @@ +/* SPDX-License-Identifier: LGPL-2.1 OR MIT */ +/* + * percpu-op.h + * + * (C) Copyright 2017-2018 - Mathieu Desnoyers + */ + +#ifndef PERCPU_OP_H +#define PERCPU_OP_H + +#include +#include +#include +#include +#include "rseq.h" +#include "cpu-op.h" + +static inline uint32_t percpu_current_cpu(void) +{ + return rseq_current_cpu(); +} + +static inline __attribute__((always_inline)) +int percpu_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, + int cpu) +{ + int ret; + + ret = rseq_cmpeqv_storev(v, expect, newv, cpu); + if (rseq_unlikely(ret)) { + if (ret > 0) + return ret; + return cpu_op_cmpeqv_storev(v, expect, newv, cpu); + } + return 0; +} + +static inline __attribute__((always_inline)) +int percpu_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot, + off_t voffp, intptr_t *load, int cpu) +{ + int ret; + + ret = rseq_cmpnev_storeoffp_load(v, expectnot, voffp, load, cpu); + if (rseq_unlikely(ret)) { + if (ret > 0) + return ret; + return cpu_op_cmpnev_storeoffp_load(v, expectnot, voffp, + load, cpu); + } + return 0; +} + +static inline __attribute__((always_inline)) +int percpu_addv(intptr_t *v, intptr_t count, int cpu) +{ + if (rseq_unlikely(rseq_addv(v, count, cpu))) + return cpu_op_addv(v, count, cpu); + return 0; +} + +static inline __attribute__((always_inline)) +int percpu_cmpeqv_storev_storev(intptr_t *v, intptr_t expect, + intptr_t *v2, intptr_t newv2, + intptr_t newv, int cpu) +{ + int ret; + + ret = rseq_cmpeqv_trystorev_storev(v, expect, v2, newv2, + newv, cpu); + if (rseq_unlikely(ret)) { + if (ret > 0) + return ret; + return cpu_op_cmpeqv_storev_storev(v, expect, v2, newv2, + newv, cpu); + } + return 0; +} + +static inline __attribute__((always_inline)) +int percpu_cmpeqv_storev_storev_release(intptr_t *v, intptr_t expect, + intptr_t *v2, intptr_t newv2, + intptr_t newv, int cpu) +{ + int ret; + + ret = rseq_cmpeqv_trystorev_storev_release(v, expect, v2, newv2, + newv, cpu); + if (rseq_unlikely(ret)) { + if (ret > 0) + return ret; + return cpu_op_cmpeqv_storev_mb_storev(v, expect, v2, newv2, + newv, cpu); + } + return 0; +} + +static inline __attribute__((always_inline)) +int percpu_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect, + intptr_t *v2, intptr_t expect2, + intptr_t newv, int cpu) +{ + int ret; + + ret = rseq_cmpeqv_cmpeqv_storev(v, expect, v2, expect2, newv, cpu); + if (rseq_unlikely(ret)) { + if (ret > 0) + return ret; + return cpu_op_cmpeqv_cmpeqv_storev(v, expect, v2, expect2, + newv, cpu); + } + return 0; +} + +static inline __attribute__((always_inline)) +int percpu_cmpeqv_memcpy_storev(intptr_t *v, intptr_t expect, + void *dst, void *src, size_t len, + intptr_t newv, int cpu) +{ + int ret; + + ret = rseq_cmpeqv_trymemcpy_storev(v, expect, dst, src, len, + newv, cpu); + if (rseq_unlikely(ret)) { + if (ret > 0) + return ret; + return cpu_op_cmpeqv_memcpy_storev(v, expect, dst, src, len, + newv, cpu); + } + return 0; +} + +static inline __attribute__((always_inline)) +int percpu_cmpeqv_memcpy_storev_release(intptr_t *v, intptr_t expect, + void *dst, void *src, size_t len, + intptr_t newv, int cpu) +{ + int ret; + + ret = rseq_cmpeqv_trymemcpy_storev_release(v, expect, dst, src, len, + newv, cpu); + if (rseq_unlikely(ret)) { + if (ret > 0) + return ret; + return cpu_op_cmpeqv_memcpy_mb_storev(v, expect, dst, src, len, + newv, cpu); + } + return 0; +} + +#endif /* PERCPU_OP_H_ */