From patchwork Thu Feb 1 12:22:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Lobakin X-Patchwork-Id: 13540985 X-Patchwork-Delegate: kuba@kernel.org Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (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 C9D885D475; Thu, 1 Feb 2024 12:24:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.15 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706790275; cv=none; b=Jol6mYw+2XQFmOUf1ohW8cSJG5IFrS0FYJ0p0fUvXmKdw3gnoyqrj3JkHdyC+Jq6JLjPq048dmHlhA/ocuvJReJx8MpWqgFrM82Z+tsKAxddfQHBYJAujReP+z4AbzIczgvJhoJF4EXDcVqcJ9wqBxniZqId920UKJMDjaUgxsc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706790275; c=relaxed/simple; bh=ImMPqSa/1eG79rUA6sfyblWF47HclOUIR1Qm/VfkB8I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=frB1YgMXtZMJUC5kJhzL2SUBemVQ1txAaO/XgyqxYpVLfo1XXQwKkMQtrv8BeBdl0zMeXyI7ZHqQHqHOP6aVC7U7dS0Nb14m72MN7iGNg9JTyXfycJ7yi6JvktfkBLm4EPqArOuVt58nX5rEXc2APt/67OVHqeLoHSVkofy3IuA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=UColmj6U; arc=none smtp.client-ip=198.175.65.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="UColmj6U" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1706790274; x=1738326274; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=ImMPqSa/1eG79rUA6sfyblWF47HclOUIR1Qm/VfkB8I=; b=UColmj6UjYpuFnHYazC+YM32SRoo6Aiu3Pk4whCiHAg9YTxazctDMv1E KmpR+4HbEmXhevo8puS7sadasC5AkmNnMDr3JHXJZEcDUvFRdYBVFPiDT A623aU914jEpZFNQ43klEtbzzntJ/8YRnkt6rRajqYKDuKHcX9z5i3O1b Wj7CDFl2A8gb8s8kzlzXV3ucBx8lZb9EV+KBwnuU0PzcLAiJZ7Qzu5g1i aR+uF4EZ9YF7xqXzmKcwYxSndbdg2nzwICX8psYzNG1zfSd7sp0wtOqeO 56vVproQKMdeVH57NncvY3tBPz3OKFay5Jdwg826m/1xRFwGGlQOXM6vU Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10969"; a="3747109" X-IronPort-AV: E=Sophos;i="6.05,234,1701158400"; d="scan'208";a="3747109" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2024 04:24:34 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,234,1701158400"; d="scan'208";a="4499125" Received: from newjersey.igk.intel.com ([10.102.20.203]) by orviesa004.jf.intel.com with ESMTP; 01 Feb 2024 04:24:28 -0800 From: Alexander Lobakin To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Alexander Lobakin , Michal Swiatkowski , Marcin Szycik , Wojciech Drewek , Yury Norov , Andy Shevchenko , Rasmus Villemoes , Alexander Potapenko , Jiri Pirko , Ido Schimmel , Przemek Kitszel , Simon Horman , linux-btrfs@vger.kernel.org, dm-devel@redhat.com, ntfs3@lists.linux.dev, linux-s390@vger.kernel.org, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v5 12/21] bitmap: introduce generic optimized bitmap_size() Date: Thu, 1 Feb 2024 13:22:07 +0100 Message-ID: <20240201122216.2634007-13-aleksander.lobakin@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240201122216.2634007-1-aleksander.lobakin@intel.com> References: <20240201122216.2634007-1-aleksander.lobakin@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org The number of times yet another open coded `BITS_TO_LONGS(nbits) * sizeof(long)` can be spotted is huge. Some generic helper is long overdue. Add one, bitmap_size(), but with one detail. BITS_TO_LONGS() uses DIV_ROUND_UP(). The latter works well when both divident and divisor are compile-time constants or when the divisor is not a pow-of-2. When it is however, the compilers sometimes tend to generate suboptimal code (GCC 13): 48 83 c0 3f add $0x3f,%rax 48 c1 e8 06 shr $0x6,%rax 48 8d 14 c5 00 00 00 00 lea 0x0(,%rax,8),%rdx %BITS_PER_LONG is always a pow-2 (either 32 or 64), but GCC still does full division of `nbits + 63` by it and then multiplication by 8. Instead of BITS_TO_LONGS(), use ALIGN() and then divide by 8. GCC: 8d 50 3f lea 0x3f(%rax),%edx c1 ea 03 shr $0x3,%edx 81 e2 f8 ff ff 1f and $0x1ffffff8,%edx Now it shifts `nbits + 63` by 3 positions (IOW performs fast division by 8) and then masks bits[2:0]. bloat-o-meter: add/remove: 0/0 grow/shrink: 20/133 up/down: 156/-773 (-617) Clang does it better and generates the same code before/after starting from -O1, except that with the ALIGN() approach it uses %edx and thus still saves some bytes: add/remove: 0/0 grow/shrink: 9/133 up/down: 18/-538 (-520) Note that we can't expand DIV_ROUND_UP() by adding a check and using this approach there, as it's used in array declarations where expressions are not allowed. Add this helper to tools/ as well. Reviewed-by: Przemek Kitszel Acked-by: Yury Norov Signed-off-by: Alexander Lobakin Signed-off-by: Yury Norov --- include/linux/bitmap.h | 8 +++++--- include/linux/cpumask.h | 2 +- tools/include/linux/bitmap.h | 7 ++++--- drivers/md/dm-clone-metadata.c | 5 ----- drivers/s390/cio/idset.c | 2 +- lib/math/prime_numbers.c | 2 -- 6 files changed, 11 insertions(+), 15 deletions(-) diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 7ca0379be8c1..9a6a27a7f675 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -218,9 +218,11 @@ void bitmap_fold(unsigned long *dst, const unsigned long *orig, #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) +#define bitmap_size(nbits) (ALIGN(nbits, BITS_PER_LONG) / BITS_PER_BYTE) + static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) { - unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); + unsigned int len = bitmap_size(nbits); if (small_const_nbits(nbits)) *dst = 0; @@ -230,7 +232,7 @@ static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) static inline void bitmap_fill(unsigned long *dst, unsigned int nbits) { - unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); + unsigned int len = bitmap_size(nbits); if (small_const_nbits(nbits)) *dst = ~0UL; @@ -241,7 +243,7 @@ static inline void bitmap_fill(unsigned long *dst, unsigned int nbits) static inline void bitmap_copy(unsigned long *dst, const unsigned long *src, unsigned int nbits) { - unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); + unsigned int len = bitmap_size(nbits); if (small_const_nbits(nbits)) *dst = *src; diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index cfb545841a2c..a2064c2a9441 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -839,7 +839,7 @@ static inline int cpulist_parse(const char *buf, struct cpumask *dstp) */ static inline unsigned int cpumask_size(void) { - return BITS_TO_LONGS(large_cpumask_bits) * sizeof(long); + return bitmap_size(large_cpumask_bits); } /* diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h index 8c6852dba04f..210c13b1b857 100644 --- a/tools/include/linux/bitmap.h +++ b/tools/include/linux/bitmap.h @@ -26,13 +26,14 @@ bool __bitmap_intersects(const unsigned long *bitmap1, #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) +#define bitmap_size(nbits) (ALIGN(nbits, BITS_PER_LONG) / BITS_PER_BYTE) + static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) { if (small_const_nbits(nbits)) *dst = 0UL; else { - int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long); - memset(dst, 0, len); + memset(dst, 0, bitmap_size(nbits)); } } @@ -84,7 +85,7 @@ static inline void bitmap_or(unsigned long *dst, const unsigned long *src1, */ static inline unsigned long *bitmap_zalloc(int nbits) { - return calloc(1, BITS_TO_LONGS(nbits) * sizeof(unsigned long)); + return calloc(1, bitmap_size(nbits)); } /* diff --git a/drivers/md/dm-clone-metadata.c b/drivers/md/dm-clone-metadata.c index c43d55672bce..47c1fa7aad8b 100644 --- a/drivers/md/dm-clone-metadata.c +++ b/drivers/md/dm-clone-metadata.c @@ -465,11 +465,6 @@ static void __destroy_persistent_data_structures(struct dm_clone_metadata *cmd) /*---------------------------------------------------------------------------*/ -static size_t bitmap_size(unsigned long nr_bits) -{ - return BITS_TO_LONGS(nr_bits) * sizeof(long); -} - static int __dirty_map_init(struct dirty_map *dmap, unsigned long nr_words, unsigned long nr_regions) { diff --git a/drivers/s390/cio/idset.c b/drivers/s390/cio/idset.c index 0a1105a483bf..e5f28370a903 100644 --- a/drivers/s390/cio/idset.c +++ b/drivers/s390/cio/idset.c @@ -18,7 +18,7 @@ struct idset { static inline unsigned long idset_bitmap_size(int num_ssid, int num_id) { - return BITS_TO_LONGS(num_ssid * num_id) * sizeof(unsigned long); + return bitmap_size(size_mul(num_ssid, num_id)); } static struct idset *idset_new(int num_ssid, int num_id) diff --git a/lib/math/prime_numbers.c b/lib/math/prime_numbers.c index d42cebf7407f..d3b64b10da1c 100644 --- a/lib/math/prime_numbers.c +++ b/lib/math/prime_numbers.c @@ -6,8 +6,6 @@ #include #include -#define bitmap_size(nbits) (BITS_TO_LONGS(nbits) * sizeof(unsigned long)) - struct primes { struct rcu_head rcu; unsigned long last, sz;