From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8709717BCE; Mon, 28 Apr 2025 20:06:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745870788; cv=none; b=dHg+Qu1S3I2LucK1LUxx3bsHs1L2xpwkf0NElgT3vayHo8inATods1yLhBpec0R5QLmrGy/dkE4gJTQ6DJeDBQyZddZzTKXKWwnN7N3iUaRYDU6C7U3PoZFgCwNcdNARrL0esr2Rsf5yYvWtXVXdlJVPrGfF6xTrKt1tVQ3QSow= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745870788; c=relaxed/simple; bh=JL45IsbMEvUYf3578oAfm2Zd40um3q1nclUnExaEMjM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AnNieZ5KDiVw8ItV+nItisb55vaz9o7pzWVHrJDSW71NFW3dgdrP8Em0F/C0JbP9/axkA5yHMdVGgatFl7gYG0izWkBxOwEmR10Bn4ZjWvcJj/9hYOod1OlkYU2+eTDtUpK7EOLseD+QhTkGn2yUq0Mswsfb5uN7gaXr0F6Eklo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bpkNZqCH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bpkNZqCH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AFDCC4CEE4; Mon, 28 Apr 2025 20:06:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745870787; bh=JL45IsbMEvUYf3578oAfm2Zd40um3q1nclUnExaEMjM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bpkNZqCH6IYVHTPO1fgeVKsLENy91jyySTB+H50aC2cg+o/bXoWiRbAz/x3rsVkFl 3hvcr9NXo6gVfFhmAWt0eScvArmeDuopyB0AfIWLBTOU9Jz1QwvfLZJjzMWTXHUNBl 9jpEQTnjxcqhnTfSqyKAXJhbcyoSSzfW0WMzky0lQsYaI3gbRhTbjPNcsNiIeQvYXk quFbECFCwoCMXiBLUZ6DsNzSfl60l1BaQ35iTorhrZaYggBusojNrvb8HRYPEUW9Og 2vbiFBxKbhVz+E+1FB/CuAIJzfMrLwktIN1XMklsM+zGGk/KGGJ/HgdupqSJwgg6ND ARRXhj1tSO+fA== Date: Mon, 28 Apr 2025 13:06:25 -0700 From: Namhyung Kim To: "T.J. Mercier" Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests/bpf: Fix kmem_cache iterator draining Message-ID: References: <20250428180256.1482899-1-tjmercier@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250428180256.1482899-1-tjmercier@google.com> Hello, On Mon, Apr 28, 2025 at 06:02:54PM +0000, T.J. Mercier wrote: > The closing parentheses around the read syscall is misplaced, causing > single byte reads from the iterator instead of buf sized reads. While > the end result is the same, many more read calls than necessary are > performed. > > $ tools/testing/selftests/bpf/vmtest.sh "./test_progs -t kmem_cache_iter" > 145/1 kmem_cache_iter/check_task_struct:OK > 145/2 kmem_cache_iter/check_slabinfo:OK > 145/3 kmem_cache_iter/open_coded_iter:OK > 145 kmem_cache_iter:OK > Summary: 1/3 PASSED, 0 SKIPPED, 0 FAILED > > Fixes: a496d0cdc84d ("selftests/bpf: Add a test for kmem_cache_iter") > Signed-off-by: T.J. Mercier Oops, thanks for fixing this. Acked-by: Namhyung Kim Thanks, Namhyung > --- > tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c b/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c > index 8e13a3416a21..1de14b111931 100644 > --- a/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c > +++ b/tools/testing/selftests/bpf/prog_tests/kmem_cache_iter.c > @@ -104,7 +104,7 @@ void test_kmem_cache_iter(void) > goto destroy; > > memset(buf, 0, sizeof(buf)); > - while (read(iter_fd, buf, sizeof(buf) > 0)) { > + while (read(iter_fd, buf, sizeof(buf)) > 0) { > /* Read out all contents */ > printf("%s", buf); > } > > base-commit: b4432656b36e5cc1d50a1f2dc15357543add530e > -- > 2.49.0.906.g1f30a19c02-goog >