From patchwork Wed May 28 08:21:18 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Ellerman X-Patchwork-Id: 353272 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 9C3CD1400CF for ; Wed, 28 May 2014 18:22:34 +1000 (EST) Received: from ozlabs.org (ozlabs.org [103.22.144.67]) by lists.ozlabs.org (Postfix) with ESMTP id 8A3C91A0776 for ; Wed, 28 May 2014 18:22:34 +1000 (EST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id D0C2D1A058F for ; Wed, 28 May 2014 18:21:25 +1000 (EST) Received: by ozlabs.org (Postfix) id BE36514009F; Wed, 28 May 2014 18:21:25 +1000 (EST) Delivered-To: linuxppc-dev@ozlabs.org Received: by ozlabs.org (Postfix, from userid 1034) id B3C551400D8; Wed, 28 May 2014 18:21:25 +1000 (EST) From: Michael Ellerman To: Subject: [PATCH 2/2] selftests/powerpc: Test the THP bug we fixed in the previous commit Date: Wed, 28 May 2014 18:21:18 +1000 Message-Id: <1401265278-29307-2-git-send-email-mpe@ellerman.id.au> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1401265278-29307-1-git-send-email-mpe@ellerman.id.au> References: <1401265278-29307-1-git-send-email-mpe@ellerman.id.au> Cc: aneesh.kumar@in.ibm.com, Paul Mackerras X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Signed-off-by: Michael Ellerman Reviewed-by: Aneesh Kumar K.V --- tools/testing/selftests/powerpc/Makefile | 2 +- tools/testing/selftests/powerpc/mm/Makefile | 18 ++++++ .../selftests/powerpc/mm/hugetlb_vs_thp_test.c | 72 ++++++++++++++++++++++ 3 files changed, 91 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/powerpc/mm/Makefile create mode 100644 tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c diff --git a/tools/testing/selftests/powerpc/Makefile b/tools/testing/selftests/powerpc/Makefile index 316194f..b3dbe9e 100644 --- a/tools/testing/selftests/powerpc/Makefile +++ b/tools/testing/selftests/powerpc/Makefile @@ -13,7 +13,7 @@ CFLAGS := -Wall -O2 -flto -Wall -Werror -DGIT_VERSION='"$(GIT_VERSION)"' -I$(CUR export CC CFLAGS -TARGETS = pmu copyloops +TARGETS = pmu copyloops mm endif diff --git a/tools/testing/selftests/powerpc/mm/Makefile b/tools/testing/selftests/powerpc/mm/Makefile new file mode 100644 index 0000000..357ccbd --- /dev/null +++ b/tools/testing/selftests/powerpc/mm/Makefile @@ -0,0 +1,18 @@ +noarg: + $(MAKE) -C ../ + +PROGS := hugetlb_vs_thp_test + +all: $(PROGS) + +$(PROGS): ../harness.c + +run_tests: all + @-for PROG in $(PROGS); do \ + ./$$PROG; \ + done; + +clean: + rm -f $(PROGS) + +.PHONY: all run_tests clean diff --git a/tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c b/tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c new file mode 100644 index 0000000..3d8e5b0 --- /dev/null +++ b/tools/testing/selftests/powerpc/mm/hugetlb_vs_thp_test.c @@ -0,0 +1,72 @@ +#include +#include +#include + +#include "utils.h" + +/* This must match the huge page & THP size */ +#define SIZE (16 * 1024 * 1024) + +static int test_body(void) +{ + void *addr; + char *p; + + addr = (void *)0xa0000000; + + p = mmap(addr, SIZE, PROT_READ | PROT_WRITE, + MAP_HUGETLB | MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (p != MAP_FAILED) { + /* + * Typically the mmap will fail because no huge pages are + * allocated on the system. But if there are huge pages + * allocated the mmap will succeed. That's fine too, we just + * munmap here before continuing. + */ + munmap(addr, SIZE); + } + + p = mmap(addr, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (p == MAP_FAILED) { + printf("Mapping failed @ %p\n", addr); + perror("mmap"); + return 1; + } + + /* + * Either a user or kernel access is sufficient to trigger the bug. + * A kernel access is easier to spot & debug, as it will trigger the + * softlockup or RCU stall detectors, and when the system is kicked + * into xmon we get a backtrace in the kernel. + * + * A good option is: + * getcwd(p, SIZE); + * + * For the purposes of this testcase it's preferable to spin in + * userspace, so the harness can kill us if we get stuck. That way we + * see a test failure rather than a dead system. + */ + *p = 0xf; + + munmap(addr, SIZE); + + return 0; +} + +static int test_main(void) +{ + int i; + + /* 10,000 because it's a "bunch", and completes reasonably quickly */ + for (i = 0; i < 10000; i++) + if (test_body()) + return 1; + + return 0; +} + +int main(void) +{ + return test_harness(test_main, "hugetlb_vs_thp"); +}