From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37790ECDE46 for ; Wed, 24 Oct 2018 16:23:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF8D32075D for ; Wed, 24 Oct 2018 16:23:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EF8D32075D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727046AbeJYAwS (ORCPT ); Wed, 24 Oct 2018 20:52:18 -0400 Received: from mga11.intel.com ([192.55.52.93]:37466 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726433AbeJYAwR (ORCPT ); Wed, 24 Oct 2018 20:52:17 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Oct 2018 09:23:34 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,421,1534834800"; d="scan'208";a="244017587" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.126]) by orsmga004.jf.intel.com with ESMTP; 24 Oct 2018 09:23:34 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 8B24A30137B; Wed, 24 Oct 2018 09:23:34 -0700 (PDT) Date: Wed, 24 Oct 2018 09:23:34 -0700 From: Andi Kleen To: kan.liang@linux.intel.com Cc: peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org, bp@alien8.de, eranian@google.com Subject: Re: [PATCH 1/2] perf: Add munmap callback Message-ID: <20181024162334.GG6218@tassilo.jf.intel.com> References: <20181024151116.30935-1-kan.liang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181024151116.30935-1-kan.liang@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > +void perf_event_munmap(void) > +{ > + struct perf_cpu_context *cpuctx; > + unsigned long flags; > + struct pmu *pmu; > + > + local_irq_save(flags); > + list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { Would be good have a fast path here that checks for the list being empty without disabling the interrupts. munmap can be somewhat hot. I think it's ok to make it slower with perf running, but we shouldn't impact it without perf. -Andi