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[2620:137:e000::3:1]) by mx.google.com with ESMTPS id w2-20020a817b02000000b0059f5bf19c05si10721004ywc.185.2023.10.25.01.38.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Oct 2023 01:38:47 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) client-ip=2620:137:e000::3:1; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=kHQsA7qo; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by morse.vger.email (Postfix) with ESMTP id D69CE802091B; Wed, 25 Oct 2023 01:38:44 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at morse.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233940AbjJYIiZ (ORCPT + 26 others); Wed, 25 Oct 2023 04:38:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232720AbjJYIiX (ORCPT ); Wed, 25 Oct 2023 04:38:23 -0400 Received: from mail-wm1-x349.google.com (mail-wm1-x349.google.com [IPv6:2a00:1450:4864:20::349]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 969759C for ; Wed, 25 Oct 2023 01:38:20 -0700 (PDT) Received: by mail-wm1-x349.google.com with SMTP id 5b1f17b1804b1-4083a670d25so38300135e9.0 for ; Wed, 25 Oct 2023 01:38:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698223099; x=1698827899; 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=qB8yrxWHAh81UTz2RSBiyIh2HT/FiKCzYUt6+8G2cno=; b=kHQsA7qolOWtP+yl3qebczcFLWcIcWcT7CCECO/PlQ6nBdpRGMAUxbEDX+ptZLNEen wjxty13x4Uqwwgaq4Rih3CBjnimugwg9NTjA5VGMBHqs0Hql3qtYNidxbCeIN5OMeAQs nvyAQyA5OMD1Kd5CFhqAYfwSVrAOtjYTii1mDw2V1t4xLOmm8wUKmQ/Ehxyws31MqRAh BMuiIZRxFmwv6SA4HVr5QzL+tf5apmu6wc2o7dSlKFC9lRoho6Iv2He9nH9AjUJ/0tNu QyySzZIySgNTFCfxAUCpwXUT7XcMjXexC9AS4RA+eyC8kexRDb3uHhDjZOS59DID0w+W 7DAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698223099; x=1698827899; 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=qB8yrxWHAh81UTz2RSBiyIh2HT/FiKCzYUt6+8G2cno=; b=m8r8xiASessi5xU6yldm9X4VuTgmYnqWSb60RUFb9L0McFXVTKxEATLNktmxyw4aq2 jR55abdHchFaIWnclV/7iEi4qEtGn04vhe5G2IpKU3WNgrt0+Y5xq4YGindXdFTBXODd wtrVoZLNqw725Hmajh6037Ko/l/Vul+QJ8FprShNFnFAVTOKciptXFicnffD6NU+pAH1 2xlfI0zMM9CYFp07UGep650BrrOLUOD+CG+nShIoAYGP4ETKjeFTUVJu7pAmrZc0lDkK 1K5aZWdugwsnkHYugMCN0LmFHEQoP1Cp5xwOKph5hRJNdXDufQ90JkYun3SYF/9WM6tH GFPg== X-Gm-Message-State: AOJu0YxGAQoorLFX3w2gOMG/g9VksOjr19Zks/E26Cc1r+/mmPDFvcYc rvxuJjkQP0WzJsgrorms/oCrb09y/38= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:541d:37f9:e2bc:817b]) (user=glider job=sendgmr) by 2002:a1c:7208:0:b0:405:37bb:d952 with SMTP id n8-20020a1c7208000000b0040537bbd952mr179583wmc.2.1698223098968; Wed, 25 Oct 2023 01:38:18 -0700 (PDT) Date: Wed, 25 Oct 2023 10:38:12 +0200 In-Reply-To: <20231025083812.456916-1-glider@google.com> Mime-Version: 1.0 References: <20231025083812.456916-1-glider@google.com> X-Mailer: git-send-email 2.42.0.758.gaed0368e0e-goog Message-ID: <20231025083812.456916-2-glider@google.com> Subject: [PATCH v9 2/2] 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 X-Spam-Status: No, score=-8.4 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on morse.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (morse.vger.email [0.0.0.0]); Wed, 25 Oct 2023 01:38:44 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1780716014335698662 X-GMAIL-MSGID: 1780716014335698662 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: 615253 [ 0.433197][ T1] test_bitmap: Time spent in test_bitmap_write_perf: 916313 (numbers from a Intel(R) Xeon(R) Gold 6154 CPU @ 3.00GHz machine running QEMU). Signed-off-by: Alexander Potapenko Reviewed-by: Andy Shevchenko --- This patch was previously part of the "Implement MTE tag compression for swapped pages" series (https://lore.kernel.org/linux-arm-kernel/20231011172836.2579017-4-glider@google.com/T/) 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/) 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==0 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 | 177 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 177 insertions(+) diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index f2ea9f30c7c5d..a4195c7376840 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -71,6 +71,17 @@ __check_eq_uint(const char *srcfile, unsigned int line, return true; } +static bool __init +__check_eq_ulong(const char *srcfile, unsigned int line, + const unsigned long exp_ulong, unsigned long x) +{ + if (exp_ulong != x) { + pr_err("[%s:%u] expected %lu, got %lu\n", + srcfile, line, exp_ulong, x); + return false; + } + return true; +} static bool __init __check_eq_bitmap(const char *srcfile, unsigned int line, @@ -186,6 +197,7 @@ __check_eq_str(const char *srcfile, unsigned int line, }) #define expect_eq_uint(...) __expect_eq(uint, ##__VA_ARGS__) +#define expect_eq_ulong(...) __expect_eq(ulong, ##__VA_ARGS__) #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__) @@ -1222,6 +1234,168 @@ static void __init test_bitmap_const_eval(void) BUILD_BUG_ON(~var != ~BIT(25)); } +/* + * 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 pattern. + */ +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 = 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 = 0; bit <= 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 = 0; i < TEST_BIT_LEN; i++) { + bitmap_write(bitmap, ~0UL, i, 0); + expect_eq_bitmap(exp_bitmap, bitmap, TEST_BIT_LEN); + } + + for (nbits = BITS_PER_LONG; nbits >= 1; nbits--) { + w = IS_ENABLED(CONFIG_64BIT) ? 0xdeadbeefdeadbeefUL + : 0xdeadbeefUL; + w >>= (BITS_PER_LONG - nbits); + for (i = 0; i <= TEST_BIT_LEN - nbits; i++) { + bitmap_copy(bitmap, pat_bitmap, TEST_BIT_LEN); + bitmap_copy(exp_bitmap, pat_bitmap, TEST_BIT_LEN); + for (n = 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 = bitmap_read(bitmap, i, nbits); + expect_eq_ulong(r, w); + } + } +} + +static void __init test_bitmap_read_write(void) +{ + unsigned char *pattern[3] = {"", "all:1/2", "all"}; + DECLARE_BITMAP(bitmap, TEST_BIT_LEN); + unsigned long zero_bits = 0, bits_per_long = 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 = 0; i < TEST_BIT_LEN - 7; i++) { + bitmap_zero(bitmap, TEST_BIT_LEN); + + bitmap_write(bitmap, 0b10101UL, i, 5); + val = bitmap_read(bitmap, i, 5); + expect_eq_ulong(0b10101UL, val); + + bitmap_write(bitmap, 0b101UL, i + 5, 3); + val = bitmap_read(bitmap, i + 5, 3); + expect_eq_ulong(0b101UL, val); + + val = bitmap_read(bitmap, i, 8); + expect_eq_ulong(0b10110101UL, val); + } + + for (pi = 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 = ktime_get(); + for (cnt = 0; cnt < 5; cnt++) { + for (nbits = 1; nbits <= BITS_PER_LONG; nbits++) { + for (i = 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 = 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 = 0xfeedface; + ktime_t time; + + bitmap_zero(bitmap, TEST_BIT_LEN); + time = ktime_get(); + for (cnt = 0; cnt < 5; cnt++) { + for (nbits = 1; nbits <= BITS_PER_LONG; nbits++) { + for (i = 0; i < TEST_BIT_LEN; i++) { + if (i + nbits > TEST_BIT_LEN) + break; + bitmap_write(bitmap, val, i, nbits); + } + } + } + time = 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(); @@ -1237,6 +1411,9 @@ 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(); test_find_nth_bit(); test_for_each_set_bit();