From patchwork Thu Oct 26 13:59:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Potapenko X-Patchwork-Id: 158555 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:d641:0:b0:403:3b70:6f57 with SMTP id cy1csp694830vqb; Thu, 26 Oct 2023 06:59:45 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEHas19c4q5T6U10zg5+8tSB51lcVm2vumAW2hRQvnse5OdSJa8MUnDuGxj2YGXrf0BmhHC X-Received: by 2002:a25:292:0:b0:d9a:49bb:b8b1 with SMTP id 140-20020a250292000000b00d9a49bbb8b1mr16513777ybc.4.1698328785008; Thu, 26 Oct 2023 06:59:45 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1698328784; cv=none; d=google.com; s=arc-20160816; b=VCPkg4300tRTL/DYAlmmSN4713CWIoWOSv1l3cHPwaDDZkblrrbDpcmiEiahtGrc8y h/wAVfqK8P5zB8BUS3c1JRhkzFqHTypyWCyjmrcxEu+N7AKEibGRk8q2Y8l33qYTUIF/ Ro5NjLdaweKLVJ3bygAp732g2zeVnE+dHr58ZBYpZEyEspJABfJ/nf8HmcYgeuNwLthc aOc0pAjXLJtyjbSQOCjfl84BiYy7QXhD6XqqYb+oNJjBEeuSXYEeB+mX+OpfeY9DwZnc +6M2IeHgGPvKB3pEdahPLMKbHBSC0YRNG8pa8i4Sci5ZxqY0KUxodfKM495i70p8XCUD EN4Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:mime-version:date :dkim-signature; bh=dAvhcHsUDf2ItWBwevxZ96vnhxr2cV7fa3pJ8laFriQ=; fh=GmoqtqK5o+3hw8duGAYBcfcrbmWz8zn7GJB0HJXGJL0=; b=I0C/v9UuCoTQhbzMhZm6+ZPQAdMYYEoPfZDzHrdbgncPoCIFlqA9vzRz/guq2fPrFg fmiqLfBqFxHie2K0z7/Sj14LnLZ3n2zcblWPgQPZbN5BSWPisCC+saNdSn16Dlyyr3JH nXXx/vEF73tBmVPbKye2hMj2Qq2qBJac65UTjcYL8MpIUnDlbILFzBr/yt7gC3Qlvf0t Ij4ISkO0ZGeDJpDUDgNIocpTFFTrFoKde0ftGABC/of87hc+B7maYN1YP0Fw8C+A+Dhw nGw08angluJqbHnmQLqQ4m4BUQ8G0AyprujHqZdf5IonUmAfo8t5/besvpvd8T/Bct8c 3oow== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=CrpZPQ3X; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 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 agentk.vger.email (agentk.vger.email. [2620:137:e000::3:2]) by mx.google.com with ESMTPS id w3-20020a25ac03000000b00d7bac6678absi14316653ybi.668.2023.10.26.06.59.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Oct 2023 06:59:44 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) client-ip=2620:137:e000::3:2; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=CrpZPQ3X; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 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 agentk.vger.email (Postfix) with ESMTP id E528A801B6CB; Thu, 26 Oct 2023 06:59:38 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at agentk.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345110AbjJZN7X (ORCPT + 26 others); Thu, 26 Oct 2023 09:59:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235012AbjJZN7V (ORCPT ); Thu, 26 Oct 2023 09:59:21 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 03DAE1B9 for ; Thu, 26 Oct 2023 06:59:17 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5af16e00fadso4579847b3.0 for ; Thu, 26 Oct 2023 06:59:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698328757; x=1698933557; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=dAvhcHsUDf2ItWBwevxZ96vnhxr2cV7fa3pJ8laFriQ=; b=CrpZPQ3X0jftiRgbMbOYCWq8HNZxpYJ59a7I5tQ4wIEpcTYkec43ab2zjVqcCSjoPA oRDBiBDaZSXprg72p57uWgCOVL66RWinA+LLo0qlU1tXrmugF5Hi1+hmKHOI+uV0so+A noVnHSfGtuhpKBozUcFQJ9J8hvztKplBcEYjwng9RUIT5bHhobSCyuZt5PVS5izZPDZW 5Id2Q1N5BBvebRCcUkwvBr5ceDvjlGpftB7Fz8E+pZg8531HoAI7sGQKxlpxZRyl89AZ YA3PcT6tKtOQMifKeppMIBLiH6z1EddOkmsWObJAB8PWbWIjMTfRSluMiJMSgZXBfMAO wpXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698328757; x=1698933557; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=dAvhcHsUDf2ItWBwevxZ96vnhxr2cV7fa3pJ8laFriQ=; b=ENM4X5BIBipJjexWpNApF8mIH01zOF26UidzAeqLresRJW4l27iyIId2hXdRTtrY2T 2L7wJRczb0gKVSkTP+3V7laEJvpIvdtoB76Il6K3Il8MzrEGT5x+tekkyhnrZzNMyNOJ Vd/hlSLhAO3RxtcW4mLMxax25qk7ixrHlrcU46hk6DtPq1a5jsDeL6dRuO3nYW1ww8hs DzpMJnY6+NbJ2N/RceeeHb62Iu6HrARcdPhJehcetibxDEMVvsEcI253FaO8bYUQOM2N E1B9ieynxEXghITrRl3TEhZVg6X0w+sjWWAhBAyHOVLKLb6ntDcN3/cCjbIfzJVZvkzu RY4Q== X-Gm-Message-State: AOJu0YzVgig5pu4nsoU8L38I/7oniIcVGozZWtM8Cl2jVxi4C4D/nus1 2X9m42V0GXVeptvaqLzzjpMRPyDLKmU= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:6c48:d4b4:c637:b013]) (user=glider job=sendgmr) by 2002:a0d:dfc3:0:b0:5a8:28e5:ca68 with SMTP id i186-20020a0ddfc3000000b005a828e5ca68mr416013ywe.5.1698328756969; Thu, 26 Oct 2023 06:59:16 -0700 (PDT) Date: Thu, 26 Oct 2023 15:59:11 +0200 Mime-Version: 1.0 X-Mailer: git-send-email 2.42.0.758.gaed0368e0e-goog Message-ID: <20231026135912.1214302-1-glider@google.com> Subject: [PATCH v10 1/2] lib/bitmap: add 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, Arnd Bergmann 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 agentk.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 (agentk.vger.email [0.0.0.0]); Thu, 26 Oct 2023 06:59:39 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1780826803952270015 X-GMAIL-MSGID: 1780826803952270015 From: Syed Nayyar Waris The two new functions allow reading/writing values of length up to BITS_PER_LONG bits at arbitrary position in the bitmap. The code was taken from "bitops: Introduce the for_each_set_clump macro" by Syed Nayyar Waris with a number of changes and simplifications: - instead of using roundup(), which adds an unnecessary dependency on , we calculate space as BITS_PER_LONG-offset; - indentation is reduced by not using else-clauses (suggested by checkpatch for bitmap_get_value()); - bitmap_get_value()/bitmap_set_value() are renamed to bitmap_read() and bitmap_write(); - some redundant computations are omitted. Cc: Arnd Bergmann Signed-off-by: Syed Nayyar Waris Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/lkml/fe12eedf3666f4af5138de0e70b67a07c7f40338.1592224129.git.syednwaris@gmail.com/ Suggested-by: Yury Norov Co-developed-by: Alexander Potapenko 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/bitmap: add bitmap_{set,get}_value()" (https://lore.kernel.org/lkml/20230720173956.3674987-2-glider@google.com/) v10: - update comments as requested by Andy Shevchenko v8: - as suggested by Andy Shevchenko, handle reads/writes of more than BITS_PER_LONG bits, add a note for 32-bit systems v7: - Address comments by Yury Norov, Andy Shevchenko, Rasmus Villemoes: - update code comments; - get rid of GENMASK(); - s/assign_bit/__assign_bit; - more vertical whitespace for better readability; - more compact code for bitmap_write() (now for real) v6: - As suggested by Yury Norov, do not require bitmap_read(..., 0) to return 0. v5: - Address comments by Yury Norov: - updated code comments and patch title/description - replace GENMASK(nbits - 1, 0) with BITMAP_LAST_WORD_MASK(nbits) - more compact bitmap_write() implementation v4: - Address comments by Andy Shevchenko and Yury Norov: - prevent passing values >= 64 to GENMASK() - fix commit authorship - change comments - check for unlikely(nbits==0) - drop unnecessary const declarations - fix kernel-doc comments - rename bitmap_{get,set}_value() to bitmap_{read,write}() --- include/linux/bitmap.h | 78 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 03644237e1efb..f5745b505a194 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -77,6 +77,10 @@ struct device; * bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst * bitmap_get_value8(map, start) Get 8bit value from map at start * bitmap_set_value8(map, value, start) Set 8bit value to map at start + * bitmap_read(map, start, nbits) Read an nbits-sized value from + * map at start + * bitmap_write(map, value, start, nbits) Write an nbits-sized value to + * map at start * * Note, bitmap_zero() and bitmap_fill() operate over the region of * unsigned longs, that is, bits behind bitmap till the unsigned long @@ -599,6 +603,80 @@ static inline void bitmap_set_value8(unsigned long *map, unsigned long value, map[index] |= value << offset; } +/** + * bitmap_read - read a value of n-bits from the memory region + * @map: address to the bitmap memory region + * @start: bit offset of the n-bit value + * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG + * + * Returns: value of @nbits bits located at the @start bit offset within the + * @map memory region. For @nbits = 0 and @nbits > BITS_PER_LONG the return + * value is undefined. + */ +static inline unsigned long bitmap_read(const unsigned long *map, + unsigned long start, + unsigned long nbits) +{ + size_t index = BIT_WORD(start); + unsigned long offset = start % BITS_PER_LONG; + unsigned long space = BITS_PER_LONG - offset; + unsigned long value_low, value_high; + + if (unlikely(!nbits || nbits > BITS_PER_LONG)) + return 0; + + if (space >= nbits) + return (map[index] >> offset) & BITMAP_LAST_WORD_MASK(nbits); + + value_low = map[index] & BITMAP_FIRST_WORD_MASK(start); + value_high = map[index + 1] & BITMAP_LAST_WORD_MASK(start + nbits); + return (value_low >> offset) | (value_high << space); +} + +/** + * bitmap_write - write n-bit value within a memory region + * @map: address to the bitmap memory region + * @value: value to write, clamped to nbits + * @start: bit offset of the n-bit value + * @nbits: size of value in bits, nonzero, up to BITS_PER_LONG. + * + * bitmap_write() behaves as-if implemented as @nbits calls of __assign_bit(), + * i.e. bits beyond @nbits are ignored: + * + * for (bit = 0; bit < nbits; bit++) + * __assign_bit(start + bit, bitmap, val & BIT(bit)); + * + * For @nbits > BITS_PER_LONG no writes are performed. + */ +static inline void bitmap_write(unsigned long *map, + unsigned long value, + unsigned long start, unsigned long nbits) +{ + size_t index; + unsigned long offset; + unsigned long space; + unsigned long mask; + bool fit; + + if (unlikely(!nbits || nbits > BITS_PER_LONG)) + return; + + mask = BITMAP_LAST_WORD_MASK(nbits); + value &= mask; + offset = start % BITS_PER_LONG; + space = BITS_PER_LONG - offset; + fit = space >= nbits; + index = BIT_WORD(start); + + map[index] &= (fit ? (~(mask << offset)) : ~BITMAP_FIRST_WORD_MASK(start)); + map[index] |= value << offset; + if (fit) + return; + + map[index + 1] &= BITMAP_FIRST_WORD_MASK(start + nbits); + map[index + 1] |= (value >> space); +} + #endif /* __ASSEMBLY__ */ #endif /* __LINUX_BITMAP_H */ From patchwork Thu Oct 26 13:59:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Potapenko X-Patchwork-Id: 158556 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:d641:0:b0:403:3b70:6f57 with SMTP id cy1csp694868vqb; Thu, 26 Oct 2023 06:59:48 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEjntPw+ZgHHYy7spmfFW26H6Dp1WTuogfYd4RrxQq7ns9E+oGlMVrA/WZmfEPOu1y58Zut X-Received: by 2002:a25:44:0:b0:d9a:5409:60a8 with SMTP id 65-20020a250044000000b00d9a540960a8mr4807981yba.14.1698328788221; Thu, 26 Oct 2023 06:59:48 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1698328788; cv=none; d=google.com; s=arc-20160816; b=m0Rm4zBhVD66V33N8SwWjZ8Vt0wIH/UyqBCqLk6NoFdUPM4P41CARXeTg14F86EiYJ akMHWRgFGC2CkgLkXme5FZpTY/GmkIzbWXndSVGEDZ5caeRiCd9jeBj7LiOfIHj7jb9D JGRgadjcIiJgCC9x4Yicvq0ECeFxOQUrwRLtiwvmg4F6459gnAXiaiz14Y9CQTlanRCm AGQpzvCZCwpPHFrLuaa/Ry1n5PtfZzei9eL9HemZBqeoyq3uOxykV6HfbuQkl5K6sOeW UtyZUoIk06tFIeJorKSLTnSSlJxUq04J0//KZpmOHmMiF45XDGkFvpX9JX2GRpUNN+ev rxtQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=qB8yrxWHAh81UTz2RSBiyIh2HT/FiKCzYUt6+8G2cno=; fh=bwsiIJU4ZySHCYgdbJrawkDYkx7XsqbTjYxIEnch01E=; b=Ha/fBiZhgVMENEOr+YRavv/vXzpx64W/+xN84YmjRuzPHFQ5Sajf4JQ3rxypZzir8Y MKUcmSJGPgNvHhfEfdZNluaNZa/MThuL2C1ypsiNzcjIwFpCfiuUoyFqrt7ys/7YB+Ze 4hiO4ISaK4z/xNfkB3NjSqwGmzpYfQwveNpoigPgeZeJlDLMaCo2WKhg6djDl1NbQv9V aGVRX3sZCUUzFNRZoJyzalCkT5AZABN54LGYh29YHgLuYEJRmLjG79YBZ/vToUrWXmro am5qWmUhvHSj5srU7C78QS04XeLti2N5kCZOHvI8AMRpE7p+YJ6Kr515CVb2HBO4xIWN hKtA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=h7J7Ltsg; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 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 fry.vger.email (fry.vger.email. [23.128.96.38]) by mx.google.com with ESMTPS id v127-20020a25c585000000b00d9cb7da28efsi6964053ybe.205.2023.10.26.06.59.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Oct 2023 06:59:48 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) client-ip=23.128.96.38; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=h7J7Ltsg; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 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 fry.vger.email (Postfix) with ESMTP id E915A837E990; Thu, 26 Oct 2023 06:59:39 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at fry.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345165AbjJZN7Z (ORCPT + 26 others); Thu, 26 Oct 2023 09:59:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345157AbjJZN7Y (ORCPT ); Thu, 26 Oct 2023 09:59:24 -0400 Received: from mail-wr1-x449.google.com (mail-wr1-x449.google.com [IPv6:2a00:1450:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 292C81B5 for ; Thu, 26 Oct 2023 06:59:21 -0700 (PDT) Received: by mail-wr1-x449.google.com with SMTP id ffacd0b85a97d-32dceab634dso493395f8f.2 for ; Thu, 26 Oct 2023 06:59:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698328759; x=1698933559; 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=h7J7LtsgpZxHtOdWdA0PkdzYu1kUsPUOtNzTX9BXD3UX0dg5xDbwTkejvwbWUEKDDb CyLhGA9ScB4ctKzWNkCveovKVa6TEAByphiAkix+65D0hIoYqVDhrujZhqNm087chv8n RjTbN7F6JMYm773Q8Y2orIACMfGgYuvXkOE3wKwJzOdEoVjwAwPdWX0gmLtHuAKiNJZJ x7+4JLOHZb6yHF8SYVpkkgDXj1jSO3GMHekMLLi/6cdMqkjgALsJINK86BZ0xH3n80oP WpdD8mkn24CMtinomzE2G+/J8uR08K4BxUzrSM74U0n6tm77QgmLXbZTigonfMU7w8ey /0mg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698328759; x=1698933559; 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=jlfXw4ER+KBd+j9ky4GDVeuVT0/Q7dpXGMdMslBP5+c71Oo4H+NaVMgb5mhN+uXEJ7 M3LyBYFbJZgtzFD46ma0/tpJbJM7IdTYq8HhBSMWpaAX/0qg32ydDWGGheHJrRcJWuuS GoihImq/w0hCmRZE/qkN4BVuiO1pa5uKx5Wq9uH9JynwSYhVioDS0OHAv+kjY+VrcGE7 9r3I+c+0nrnra0DCiMFqTsc4bXo9+u77eMtGXMpl0beN8jQqbEB/MthUF8416qPlGtXK inM4+6unptafS5QC834/aeI+KXAaZcRC0GxUTjG4UiWPWzJDZQjm29UUwccc1EIx6B1G KCiQ== X-Gm-Message-State: AOJu0Yy4tgD6yD644IEP2qbe5I0oQR86Ust+4tZQqLnKfpsFpCRX8BKr 1z5GvEI2gPPETaa2HKPFr2AVSey6jCg= X-Received: from glider.muc.corp.google.com ([2a00:79e0:9c:201:6c48:d4b4:c637:b013]) (user=glider job=sendgmr) by 2002:a5d:54d2:0:b0:32d:974b:6de2 with SMTP id x18-20020a5d54d2000000b0032d974b6de2mr167450wrv.0.1698328759543; Thu, 26 Oct 2023 06:59:19 -0700 (PDT) Date: Thu, 26 Oct 2023 15:59:12 +0200 In-Reply-To: <20231026135912.1214302-1-glider@google.com> Mime-Version: 1.0 References: <20231026135912.1214302-1-glider@google.com> X-Mailer: git-send-email 2.42.0.758.gaed0368e0e-goog Message-ID: <20231026135912.1214302-2-glider@google.com> Subject: [PATCH v10 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 fry.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 (fry.vger.email [0.0.0.0]); Thu, 26 Oct 2023 06:59:40 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1780826807425270795 X-GMAIL-MSGID: 1780826807425270795 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();