From patchwork Mon Dec 16 21:35:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Gardon X-Patchwork-Id: 11295359 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AD5EC109A for ; Mon, 16 Dec 2019 21:36:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A33424655 for ; Mon, 16 Dec 2019 21:36:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="A2sDWiv0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727906AbfLPVgf (ORCPT ); Mon, 16 Dec 2019 16:36:35 -0500 Received: from mail-pg1-f202.google.com ([209.85.215.202]:44809 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727700AbfLPVf5 (ORCPT ); Mon, 16 Dec 2019 16:35:57 -0500 Received: by mail-pg1-f202.google.com with SMTP id o21so4746150pgm.11 for ; Mon, 16 Dec 2019 13:35:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Mr7NGohfKIO/0LLJHqW5UMZVsaNn5FVbb/vWY+9rP5E=; b=A2sDWiv0ldMYscBiHQh9dHQ5MUEBID6HNSMCZKrSzSBHe5IP+x2QVF9pvCTy0Mb8vZ 5Ucs8s2vK3fbogLXC0Ic2aeI6Fd4RWV8xtSym8CFQpUcZP9JU6RXnDr6mDoG9MfKxkF5 sOuYpCTCURyIn1E5+y/Tp7nHWEDPlz+b1uEhw3tvBpJsiHqlvz4d3D0fGrOqwLwciawL dYhiY/Mj8s3TJbo3kkRVHlFrbAh0FuUigZcxB5guESxALZymb+UViRMBtJLB1fKZdvod fqXmmv1HZ7NP3Q8+HLC6OuPvHSSq7W9tpWdOOBgdn6R7OJV2HtLmJACC0AHw8LG/DhWZ Lc+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Mr7NGohfKIO/0LLJHqW5UMZVsaNn5FVbb/vWY+9rP5E=; b=tbA99qPA7Gr2lj0VXnOMsE/qTw/8k1JU5RCvSoNvceekQDkaF1Jjs2TDe3ujv30RwS 3OnM0G429nLyguVCwC5QYpb90sx6Pvbfohy/59uv2Pm75CClh4uYnkQyvXTbQmSvBJkh tF4OUe34WeuBYkMydEoCLcggjB3FWxfHDM1Mqt835+qCcXUqtT8demsH2yprjAVz7VET yKoJRh2gmPdWXs2BIE+NljtjHx929HkGC2kU3M8yk1JSuDwHCTdkMmrshp9D4wzQ1Ain oHvUPFoVxD5YL7ZxU8ltIhe+0CNoc6/Joaykdt+Zvb9wPWmJvjJrxO8WQsWlHcRgAfGR /CTw== X-Gm-Message-State: APjAAAUqCuBV9E6hMg1UdZxwmRR3tVPUnCIo7/ttAM9vZf3En3YiMcYJ iFCOrQkjvzXegRzZKUUf9wPSKqG6uvce X-Google-Smtp-Source: APXvYqw06kZ9cCSs/wZsgCwXIpnr8tBG5tdX40Y0wfTxdez3/oaBkHCMDceobXs3YzHahMBMa1bvCejSDNxw X-Received: by 2002:a65:5809:: with SMTP id g9mr21313875pgr.146.1576532155836; Mon, 16 Dec 2019 13:35:55 -0800 (PST) Date: Mon, 16 Dec 2019 13:35:26 -0800 In-Reply-To: <20191216213532.91237-1-bgardon@google.com> Message-Id: <20191216213532.91237-4-bgardon@google.com> Mime-Version: 1.0 References: <20191216213532.91237-1-bgardon@google.com> X-Mailer: git-send-email 2.24.1.735.g03f4e72817-goog Subject: [PATCH v2 3/8] KVM: selftests: Add configurable demand paging delay From: Ben Gardon To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Paolo Bonzini , Cannon Matthews , Peter Xu , Andrew Jones , Ben Gardon Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org When running the demand paging test with the -u option, the User Fault FD handler essentially adds an arbitrary delay to page fault resolution. To enable better simulation of a real demand paging scenario, add a configurable delay to the UFFD handler. Signed-off-by: Ben Gardon --- .../selftests/kvm/demand_paging_test.c | 32 +++++++++++++++---- 1 file changed, 25 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c index a8f775dab7d4a..11de5b58995fb 100644 --- a/tools/testing/selftests/kvm/demand_paging_test.c +++ b/tools/testing/selftests/kvm/demand_paging_test.c @@ -142,12 +142,14 @@ bool quit_uffd_thread; struct uffd_handler_args { int uffd; + useconds_t delay; }; static void *uffd_handler_thread_fn(void *arg) { struct uffd_handler_args *uffd_args = (struct uffd_handler_args *)arg; int uffd = uffd_args->uffd; + useconds_t delay = uffd_args->delay; int64_t pages = 0; while (!quit_uffd_thread) { @@ -203,6 +205,8 @@ static void *uffd_handler_thread_fn(void *arg) if (!(msg.event & UFFD_EVENT_PAGEFAULT)) continue; + if (delay) + usleep(delay); addr = msg.arg.pagefault.address; r = handle_uffd_page_request(uffd, addr); if (r < 0) @@ -214,7 +218,8 @@ static void *uffd_handler_thread_fn(void *arg) } static int setup_demand_paging(struct kvm_vm *vm, - pthread_t *uffd_handler_thread) + pthread_t *uffd_handler_thread, + useconds_t uffd_delay) { int uffd; struct uffdio_api uffdio_api; @@ -252,6 +257,7 @@ static int setup_demand_paging(struct kvm_vm *vm, } uffd_args.uffd = uffd; + uffd_args.delay = uffd_delay; pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn, &uffd_args); @@ -261,7 +267,8 @@ static int setup_demand_paging(struct kvm_vm *vm, #define GUEST_MEM_SHIFT 30 /* 1G */ #define PAGE_SHIFT_4K 12 -static void run_test(enum vm_guest_mode mode, bool use_uffd) +static void run_test(enum vm_guest_mode mode, bool use_uffd, + useconds_t uffd_delay) { pthread_t vcpu_thread; pthread_t uffd_handler_thread; @@ -326,7 +333,8 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd) if (use_uffd) { /* Set up user fault fd to handle demand paging requests. */ quit_uffd_thread = false; - r = setup_demand_paging(vm, &uffd_handler_thread); + r = setup_demand_paging(vm, &uffd_handler_thread, + uffd_delay); if (r < 0) exit(-r); } @@ -373,7 +381,7 @@ static void help(char *name) int i; puts(""); - printf("usage: %s [-h] [-m mode] [-u]\n", name); + printf("usage: %s [-h] [-m mode] [-u] [-d uffd_delay_usec]\n", name); printf(" -m: specify the guest mode ID to test\n" " (default: test all supported modes)\n" " This option may be used multiple times.\n" @@ -382,7 +390,11 @@ static void help(char *name) printf(" %d: %s%s\n", i, vm_guest_mode_string(i), vm_guest_mode_params[i].supported ? " (supported)" : ""); } - printf(" -u: Use User Fault FD to handle vCPU page faults.\n"); + printf(" -u: use User Fault FD to handle vCPU page\n" + " faults.\n"); + printf(" -d: add a delay in usec to the User Fault\n" + " FD handler to simulate demand paging\n" + " overheads. Ignored without -u.\n"); puts(""); exit(0); } @@ -393,6 +405,7 @@ int main(int argc, char *argv[]) unsigned int mode; int opt, i; bool use_uffd = false; + useconds_t uffd_delay = 0; #ifdef __x86_64__ vm_guest_mode_params_init(VM_MODE_PXXV48_4K, true, true); @@ -401,7 +414,7 @@ int main(int argc, char *argv[]) vm_guest_mode_params_init(VM_MODE_P40V48_4K, true, true); #endif - while ((opt = getopt(argc, argv, "hm:u")) != -1) { + while ((opt = getopt(argc, argv, "hm:ud:")) != -1) { switch (opt) { case 'm': if (!mode_selected) { @@ -417,6 +430,11 @@ int main(int argc, char *argv[]) case 'u': use_uffd = true; break; + case 'd': + uffd_delay = strtoul(optarg, NULL, 0); + TEST_ASSERT(uffd_delay >= 0, + "A negative UFFD delay is not supported."); + break; case 'h': default: help(argv[0]); @@ -430,7 +448,7 @@ int main(int argc, char *argv[]) TEST_ASSERT(vm_guest_mode_params[i].supported, "Guest mode ID %d (%s) not supported.", i, vm_guest_mode_string(i)); - run_test(i, use_uffd); + run_test(i, use_uffd, uffd_delay); } return 0;