From nobody Sun Dec 28 02:53:20 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77403C4332F for ; Thu, 14 Dec 2023 11:07:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1443934AbjLNLGv (ORCPT ); Thu, 14 Dec 2023 06:06:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1443899AbjLNLGr (ORCPT ); Thu, 14 Dec 2023 06:06:47 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A995D11D for ; Thu, 14 Dec 2023 03:06:52 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-5e302b65cc7so9679187b3.1 for ; Thu, 14 Dec 2023 03:06:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1702552012; x=1703156812; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=hls/cSgyQjjQ+ZYtpE7D/6PwXwlUmCuSXktuDqFik/0=; b=14yvUkqnCTSNuCHpxTDADQvs1xXDNEudl2Qnq8RlTFoxV1nsja3YC7pACJvOcDUyKm lT0PTDx0uMUCP8nxwgrpu9NLBFBqmPoZw0J3ldd0M3jDAM+L0DFtMijesR4y/MT/osmj GFwyLXZiHOUaT2c1pXJXZ0kyYgDgM/nRGd+Eorm/ohgRMn+4eHlRUd74oJ3t8/8XHkyW u+nvEiKcYmjvUcraE8adwTtvZF+W9QMSLW4PZba1roHfqe7Pom8GDHOd96r6gCHPlwiD NaMcJ+I4Sd/SIdhVnFUOCHZ5aS6pu3RLlWDQ68Zt/YxF6XXkos/UEQVl+xDWIVpXzMqp REYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702552012; x=1703156812; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=hls/cSgyQjjQ+ZYtpE7D/6PwXwlUmCuSXktuDqFik/0=; b=sHFKobGW2qR1A6MU7nkol5u4oX6RZIXJr1AoSyh0XQejjg/o+MHXeghD1eTrOw/GW7 wkfMPrX0fFYsFrriXCDESi8b6+uOeWHrW5ZFjfHTB+YJ561cFURSA7/bcXOnxqD7/UqY +0N5T+B6oChu55BH+lIxbyNtTP/kq+1BZggKeRMHlqNXrcFL8s5b4DXT1rrBLQGD3qTj bsSLYzWcuPtNjA/FkvXpAXwpmEvXBPeNre8sfZTKOPTVwPf6EWH9Pc4FNhzc68bnzutH y8i+OQ73EHSBWgv9yzdJHWgKwdCqKxDyBS+Y5BsP9s530p9/hU3qyliQOYr6y1s7CA60 nSog== X-Gm-Message-State: AOJu0YxQIEIwjOKUtIYlRjui4ArvhInFFmGmSNomIqvB7ssL3Wf2WXbt YpwMcXNHxTFY0cLFMdeVmgvAW7EJdrs= X-Google-Smtp-Source: AGHT+IEjpQMwFT68NRnvlcTcCrNZBvxWm62UXqwNPKA1jIGJeOIM5XLelcRGDEhW83hxKme6Xq8vC7rpCok= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:8447:3e89:1f77:ff8a]) (user=glider job=sendgmr) by 2002:a81:fe05:0:b0:5e3:5f02:360a with SMTP id j5-20020a81fe05000000b005e35f02360amr16012ywn.9.1702552011910; Thu, 14 Dec 2023 03:06:51 -0800 (PST) Date: Thu, 14 Dec 2023 12:06:34 +0100 In-Reply-To: <20231214110639.2294687-1-glider@google.com> Mime-Version: 1.0 References: <20231214110639.2294687-1-glider@google.com> X-Mailer: git-send-email 2.43.0.472.g3155946c3a-goog Message-ID: <20231214110639.2294687-3-glider@google.com> Subject: [PATCH v10-mte 2/7] lib/test_bitmap: add tests for bitmap_{read,write}() From: Alexander Potapenko To: glider@google.com, catalin.marinas@arm.com, will@kernel.org, pcc@google.com, andreyknvl@gmail.com, andriy.shevchenko@linux.intel.com, aleksander.lobakin@intel.com, linux@rasmusvillemoes.dk, yury.norov@gmail.com, alexandru.elisei@arm.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, eugenis@google.com, syednwaris@gmail.com, william.gray@linaro.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add basic tests ensuring that values can be added at arbitrary positions of the bitmap, including those spanning into the adjacent unsigned longs. Two new performance tests, test_bitmap_read_perf() and test_bitmap_write_perf(), can be used to assess future performance improvements of bitmap_read() and bitmap_write(): [ 0.431119][ T1] test_bitmap: Time spent in test_bitmap_read_perf: 61= 5253 [ 0.433197][ T1] test_bitmap: Time spent in test_bitmap_write_perf: 9= 16313 (numbers from a Intel(R) Xeon(R) Gold 6154 CPU @ 3.00GHz machine running QEMU). Signed-off-by: Alexander Potapenko Reviewed-by: Andy Shevchenko Acked-by: Yury Norov --- v10-mte: - send this patch together with the "Implement MTE tag compression for swapped pages" Revisions v8-v12 of bitmap patches were reviewed separately from the "Implement MTE tag compression for swapped pages" series (https://lore.kernel.org/lkml/20231109151106.2385155-1-glider@google.com/) This patch was previously called "lib/test_bitmap: add tests for bitmap_{set,get}_value()" (https://lore.kernel.org/lkml/20230720173956.3674987-3-glider@google.com/) and "lib/test_bitmap: add tests for bitmap_{set,get}_value_unaligned" (https://lore.kernel.org/lkml/20230713125706.2884502-3-glider@google.com/) v12: - as suggested by Alexander Lobakin, replace expect_eq_uint() with expect_eq_ulong() and a cast v9: - use WRITE_ONCE() to prevent optimizations in test_bitmap_read_perf() - update patch description v8: - as requested by Andy Shevchenko, add tests for reading/writing sizes > BITS_PER_LONG v7: - as requested by Yury Norov, add performance tests for bitmap_read() and bitmap_write() v6: - use bitmap API to initialize test bitmaps - as requested by Yury Norov, do not check the return value of bitmap_read(..., 0) - fix a compiler warning on 32-bit systems v5: - update patch title - address Yury Norov's comments: - rename the test cases - factor out test_bitmap_write_helper() to test writing over different background patterns; - add a test case copying a nontrivial value bit-by-bit; - drop volatile v4: - Address comments by Andy Shevchenko: added Reviewed-by: and a link to the previous discussion - Address comments by Yury Norov: - expand the bitmap to catch more corner cases - add code testing that bitmap_set_value() does not touch adjacent bits - add code testing the nbits=3D=3D0 case - rename bitmap_{get,set}_value() to bitmap_{read,write}() v3: - switch to using bitmap_{set,get}_value() - change the expected bit pattern in test_set_get_value(), as the test was incorrectly assuming 0 is the LSB. --- lib/test_bitmap.c | 179 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 172 insertions(+), 7 deletions(-) diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index 65f22c2578b06..46c0154680772 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -60,18 +60,17 @@ static const unsigned long exp3_1_0[] __initconst =3D { }; =20 static bool __init -__check_eq_uint(const char *srcfile, unsigned int line, - const unsigned int exp_uint, unsigned int x) +__check_eq_ulong(const char *srcfile, unsigned int line, + const unsigned long exp_ulong, unsigned long x) { - if (exp_uint !=3D x) { - pr_err("[%s:%u] expected %u, got %u\n", - srcfile, line, exp_uint, x); + if (exp_ulong !=3D x) { + pr_err("[%s:%u] expected %lu, got %lu\n", + srcfile, line, exp_ulong, x); return false; } return true; } =20 - static bool __init __check_eq_bitmap(const char *srcfile, unsigned int line, const unsigned long *exp_bmap, const unsigned long *bmap, @@ -185,7 +184,8 @@ __check_eq_str(const char *srcfile, unsigned int line, result; \ }) =20 -#define expect_eq_uint(...) __expect_eq(uint, ##__VA_ARGS__) +#define expect_eq_ulong(...) __expect_eq(ulong, ##__VA_ARGS__) +#define expect_eq_uint(x, y) expect_eq_ulong((unsigned int)(x), (unsigned= int)(y)) #define expect_eq_bitmap(...) __expect_eq(bitmap, ##__VA_ARGS__) #define expect_eq_pbl(...) __expect_eq(pbl, ##__VA_ARGS__) #define expect_eq_u32_array(...) __expect_eq(u32_array, ##__VA_ARGS__) @@ -1245,6 +1245,168 @@ static void __init test_bitmap_const_eval(void) BUILD_BUG_ON(~var !=3D ~BIT(25)); } =20 +/* + * Test bitmap should be big enough to include the cases when start is not= in + * the first word, and start+nbits lands in the following word. + */ +#define TEST_BIT_LEN (1000) + +/* + * Helper function to test bitmap_write() overwriting the chosen byte patt= ern. + */ +static void __init test_bitmap_write_helper(const char *pattern) +{ + DECLARE_BITMAP(bitmap, TEST_BIT_LEN); + DECLARE_BITMAP(exp_bitmap, TEST_BIT_LEN); + DECLARE_BITMAP(pat_bitmap, TEST_BIT_LEN); + unsigned long w, r, bit; + int i, n, nbits; + + /* + * Only parse the pattern once and store the result in the intermediate + * bitmap. + */ + bitmap_parselist(pattern, pat_bitmap, TEST_BIT_LEN); + + /* + * Check that writing a single bit does not accidentally touch the + * adjacent bits. + */ + for (i =3D 0; i < TEST_BIT_LEN; i++) { + bitmap_copy(bitmap, pat_bitmap, TEST_BIT_LEN); + bitmap_copy(exp_bitmap, pat_bitmap, TEST_BIT_LEN); + for (bit =3D 0; bit <=3D 1; bit++) { + bitmap_write(bitmap, bit, i, 1); + __assign_bit(i, exp_bitmap, bit); + expect_eq_bitmap(exp_bitmap, bitmap, + TEST_BIT_LEN); + } + } + + /* Ensure writing 0 bits does not change anything. */ + bitmap_copy(bitmap, pat_bitmap, TEST_BIT_LEN); + bitmap_copy(exp_bitmap, pat_bitmap, TEST_BIT_LEN); + for (i =3D 0; i < TEST_BIT_LEN; i++) { + bitmap_write(bitmap, ~0UL, i, 0); + expect_eq_bitmap(exp_bitmap, bitmap, TEST_BIT_LEN); + } + + for (nbits =3D BITS_PER_LONG; nbits >=3D 1; nbits--) { + w =3D IS_ENABLED(CONFIG_64BIT) ? 0xdeadbeefdeadbeefUL + : 0xdeadbeefUL; + w >>=3D (BITS_PER_LONG - nbits); + for (i =3D 0; i <=3D TEST_BIT_LEN - nbits; i++) { + bitmap_copy(bitmap, pat_bitmap, TEST_BIT_LEN); + bitmap_copy(exp_bitmap, pat_bitmap, TEST_BIT_LEN); + for (n =3D 0; n < nbits; n++) + __assign_bit(i + n, exp_bitmap, w & BIT(n)); + bitmap_write(bitmap, w, i, nbits); + expect_eq_bitmap(exp_bitmap, bitmap, TEST_BIT_LEN); + r =3D bitmap_read(bitmap, i, nbits); + expect_eq_ulong(r, w); + } + } +} + +static void __init test_bitmap_read_write(void) +{ + unsigned char *pattern[3] =3D {"", "all:1/2", "all"}; + DECLARE_BITMAP(bitmap, TEST_BIT_LEN); + unsigned long zero_bits =3D 0, bits_per_long =3D BITS_PER_LONG; + unsigned long val; + int i, pi; + + /* + * Reading/writing zero bits should not crash the kernel. + * READ_ONCE() prevents constant folding. + */ + bitmap_write(NULL, 0, 0, READ_ONCE(zero_bits)); + /* Return value of bitmap_read() is undefined here. */ + bitmap_read(NULL, 0, READ_ONCE(zero_bits)); + + /* + * Reading/writing more than BITS_PER_LONG bits should not crash the + * kernel. READ_ONCE() prevents constant folding. + */ + bitmap_write(NULL, 0, 0, READ_ONCE(bits_per_long) + 1); + /* Return value of bitmap_read() is undefined here. */ + bitmap_read(NULL, 0, READ_ONCE(bits_per_long) + 1); + + /* + * Ensure that bitmap_read() reads the same value that was previously + * written, and two consequent values are correctly merged. + * The resulting bit pattern is asymmetric to rule out possible issues + * with bit numeration order. + */ + for (i =3D 0; i < TEST_BIT_LEN - 7; i++) { + bitmap_zero(bitmap, TEST_BIT_LEN); + + bitmap_write(bitmap, 0b10101UL, i, 5); + val =3D bitmap_read(bitmap, i, 5); + expect_eq_ulong(0b10101UL, val); + + bitmap_write(bitmap, 0b101UL, i + 5, 3); + val =3D bitmap_read(bitmap, i + 5, 3); + expect_eq_ulong(0b101UL, val); + + val =3D bitmap_read(bitmap, i, 8); + expect_eq_ulong(0b10110101UL, val); + } + + for (pi =3D 0; pi < ARRAY_SIZE(pattern); pi++) + test_bitmap_write_helper(pattern[pi]); +} + +static void __init test_bitmap_read_perf(void) +{ + DECLARE_BITMAP(bitmap, TEST_BIT_LEN); + unsigned int cnt, nbits, i; + unsigned long val; + ktime_t time; + + bitmap_fill(bitmap, TEST_BIT_LEN); + time =3D ktime_get(); + for (cnt =3D 0; cnt < 5; cnt++) { + for (nbits =3D 1; nbits <=3D BITS_PER_LONG; nbits++) { + for (i =3D 0; i < TEST_BIT_LEN; i++) { + if (i + nbits > TEST_BIT_LEN) + break; + /* + * Prevent the compiler from optimizing away the + * bitmap_read() by using its value. + */ + WRITE_ONCE(val, bitmap_read(bitmap, i, nbits)); + } + } + } + time =3D ktime_get() - time; + pr_err("Time spent in %s:\t%llu\n", __func__, time); +} + +static void __init test_bitmap_write_perf(void) +{ + DECLARE_BITMAP(bitmap, TEST_BIT_LEN); + unsigned int cnt, nbits, i; + unsigned long val =3D 0xfeedface; + ktime_t time; + + bitmap_zero(bitmap, TEST_BIT_LEN); + time =3D ktime_get(); + for (cnt =3D 0; cnt < 5; cnt++) { + for (nbits =3D 1; nbits <=3D BITS_PER_LONG; nbits++) { + for (i =3D 0; i < TEST_BIT_LEN; i++) { + if (i + nbits > TEST_BIT_LEN) + break; + bitmap_write(bitmap, val, i, nbits); + } + } + } + time =3D ktime_get() - time; + pr_err("Time spent in %s:\t%llu\n", __func__, time); +} + +#undef TEST_BIT_LEN + static void __init selftest(void) { test_zero_clear(); @@ -1261,6 +1423,9 @@ static void __init selftest(void) test_bitmap_cut(); test_bitmap_print_buf(); test_bitmap_const_eval(); + test_bitmap_read_write(); + test_bitmap_read_perf(); + test_bitmap_write_perf(); =20 test_find_nth_bit(); test_for_each_set_bit(); --=20 2.43.0.472.g3155946c3a-goog