From nobody Tue Dec 16 11:13:17 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 445A7C83F20 for ; Mon, 28 Aug 2023 18:44:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233159AbjH1Sob (ORCPT ); Mon, 28 Aug 2023 14:44:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233128AbjH1SoL (ORCPT ); Mon, 28 Aug 2023 14:44:11 -0400 Received: from mail-oi1-x236.google.com (mail-oi1-x236.google.com [IPv6:2607:f8b0:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC453B0 for ; Mon, 28 Aug 2023 11:44:09 -0700 (PDT) Received: by mail-oi1-x236.google.com with SMTP id 5614622812f47-3a85c5854deso2729443b6e.0 for ; Mon, 28 Aug 2023 11:44:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1693248248; x=1693853048; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=FplpJ0L1Cq8kvgNUXqiEcC7mn8MGISXoZpv2LNEhVNE=; b=h6EDvUKvuWejmDg99fRjBjUEH/qunGXcHME78wbCR1Gd+mkDGTdoSY+d2N+sR6qjF+ wYO5rDkOPGj7TgB/Q4slKLQeEiqhfzq8qVjXvy5RIHd/Rq4POP1Xr3fZvf7ZznTtN8ev wxy3hfsZesm9Fxf05AuBSdqobFG1q1bN7AF4eGkb5oVf2U6h1hkRhLh48EBEse+Vs5Yu BneIpKJCGjXfDBXEDUafhBuid5ZoD7BF+hV70g+OM/EjeP/HVhOtV6vr75PvHCYquZE4 NckgRs01jycoNN+j7Umz6lxHqxSBeuxTTs8d4OgzdBNP7a2Bq//PzU00pxs8ffqcKvBY zFQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693248248; x=1693853048; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=FplpJ0L1Cq8kvgNUXqiEcC7mn8MGISXoZpv2LNEhVNE=; b=eDsadepfSU1+SoT+d+YZFw1XCzhLOBgyh5gZCb8VrV6BtTtPOUn1ot2pQUQZk9WCb/ kSix3JOhD9dwD4OgH08Aqnc4eVzKrm+E8ICRfYRQA6w+GaIvuzknqztly8hMApu8WlAX IeE1WXWVwiqGztlV7eC26luyAO8Df4JOoJ13bp7NkA4H6i2ApIsKh112gzdH/1kg3Kkh hqbW2n9etGf/kOqUpoy3R93lvfINorenTY+NMdI3oVs/TnFvtm8SoAaPLuNpaYmOOvZ1 X/AbFhPImchJcQ/B+U+Wd0JoJxDJov3TgsytBVIwJ3S5j1tva0AX8IH9td5QpqBMSbyY bkgQ== X-Gm-Message-State: AOJu0YzcEvEz5agQAtxnS8kpO2rnbDRtsL6fW8f1RzW3/sZ2NMrPgf7P Pm+WCGhFirbzt6AiKIwKB2RL+sWqPQY= X-Google-Smtp-Source: AGHT+IEc12Sb51t2ikk7rn8SmMMeW5zZ1FvoL1/UoKx8dCxm2HMcoYk3C3K/NxcfEZFA913lskPYsw== X-Received: by 2002:a05:6808:d46:b0:3a8:8ea9:62de with SMTP id w6-20020a0568080d4600b003a88ea962demr12349285oik.39.1693248248606; Mon, 28 Aug 2023 11:44:08 -0700 (PDT) Received: from localhost ([2600:6c5e:2a00:5805:e348:56d4:5da8:636d]) by smtp.gmail.com with ESMTPSA id n29-20020a0568080a1d00b003a782e88fd9sm3648806oij.58.2023.08.28.11.44.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Aug 2023 11:44:08 -0700 (PDT) From: Yury Norov To: linux-kernel@vger.kernel.org Cc: Yury Norov , Andy Shevchenko , Rasmus Villemoes Subject: [PATCH 08/12] bitmap: optiimze bitmap_bitremap() Date: Mon, 28 Aug 2023 11:43:48 -0700 Message-Id: <20230828184353.5145-9-yury.norov@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230828184353.5145-1-yury.norov@gmail.com> References: <20230828184353.5145-1-yury.norov@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When 'new' map is empty, we can skip remapping entirely and return the old bit. Signed-off-by: Yury Norov --- lib/bitmap.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 9ecdc74cb6b4..2e8deeb8bf99 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -1017,12 +1017,17 @@ EXPORT_SYMBOL(__bitmap_remap); int __bitmap_bitremap(int oldbit, const unsigned long *old, const unsigned long *new, int bits) { - int w =3D bitmap_weight(new, bits); - int n =3D bitmap_pos_to_ord(old, oldbit, bits); - if (n < 0 || w =3D=3D 0) + int w, n; + + w =3D bitmap_weight(new, bits); + if (w =3D=3D 0) + return oldbit; + + n =3D bitmap_pos_to_ord(old, oldbit, bits); + if (n < 0) return oldbit; - else - return find_nth_bit(new, bits, n % w); + + return find_nth_bit(new, bits, n % w); } EXPORT_SYMBOL(__bitmap_bitremap); =20 --=20 2.39.2