From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 498BD2E091B; Thu, 4 Jun 2026 02:00:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780538438; cv=none; b=RnDaslbjCMhfTLjAXgcK0O1zkkC/yBgvomWd4BIChayF6u1YAisEEcWtXj5fbrb6kbPqRJKd0ur/PlaJKIQNayyRGI4AyUZG8ehyBYoLsNoc8rIIkvKXm4xC+VcjPRb7YE2ZX73HRJpb+ajL3l3dxkZK7Ayl0pAZJlyxEPsaCFw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780538438; c=relaxed/simple; bh=JCehyu2gPV/I2VfOKna9vLlR/ORXCcPrsHeRU6UlipY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=N0uXVdC+mV9LwNQK/SM9kQe/fTTp/clqgm6FZOCeZxkYhcz9tr2hZiIQbtXXhgrc3jCFIJm9ls+XZAR1WO1cc2C7uUKhdhXOOmyCjki9dv/ppT/mT/Gz2hYSOI0KacsX8nTbjNVi94nnOI8Qk9ZVc/POu6XyI8zcdogkhY0Egjc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SZ8dNQK/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SZ8dNQK/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5CAB1F00898; Thu, 4 Jun 2026 02:00:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780538437; bh=8GzSf2hO2QNntgr6YU/BN9DqUtL3sro1P7MtZPRxLFw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SZ8dNQK/y1dzeNRFBBRMvh9LZK2VvuICKudNiuem3sxhi+GGEPuzdp7y08JnF8o+V hb9W6NO1p57nRnFoKFP8puxspXRGabMdtTWdBIyditcwAOoYjq7tsqrJvzpXgvt8qf 9CCLjcm957s6XHOaUQNuerKEAmkXuB/ZAFACDzX5jELrKLHwnY+Z1orp9aNNro9CQn VizMUJe/Gp2r0E7X/hguqZOjzzqUdHklnUGCGHVL7lp4mk+HYrXov0I9G+8AjyZQC4 MB/ArSrq6BSBBQ7gCY4A78Fs0LdKQs4dKNJUAGMq4bwU72Lw91F4dfNl8Laz5R53MD he4ouGBATRH1w== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min Cc: Emil Tsalapatis , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 3/4] sched_ext: Add scx_cmask_test() and scx_cmask_for_each_cid() Date: Wed, 3 Jun 2026 16:00:31 -1000 Message-ID: <20260604020032.3536466-4-tj@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260604020032.3536466-1-tj@kernel.org> References: <20260604020032.3536466-1-tj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add single-bit test and iterator over set cids in an scx_cmask. v2: Bound scx_cmask_for_each_cid() to the active span. (sashiko AI) Signed-off-by: Tejun Heo --- kernel/sched/ext_cid.h | 43 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/kernel/sched/ext_cid.h b/kernel/sched/ext_cid.h index 46fd8eda0443..5745e5785e89 100644 --- a/kernel/sched/ext_cid.h +++ b/kernel/sched/ext_cid.h @@ -225,4 +225,47 @@ static inline void __scx_cmask_set(u32 cid, struct scx_cmask *m) *__scx_cmask_word(cid, m) |= BIT_U64(cid & 63); } +/** + * scx_cmask_test - test whether @cid is set in @m + * @cid: cid to test + * @m: cmask to test + * + * Return %false if @cid is outside @m's active range. Otherwise return the + * bit's value. Read via READ_ONCE so callers can race set/clear writers. + */ +static inline bool scx_cmask_test(u32 cid, const struct scx_cmask *m) +{ + if (!__scx_cmask_contains(cid, m)) + return false; + return READ_ONCE(*__scx_cmask_word(cid, m)) & BIT_U64(cid & 63); +} + +/* + * Words of bits[] the active range spans, 0 if empty. Tighter than the storage + * SCX_CMASK_NR_WORDS() sizes for the worst-case base alignment. + */ +static inline u32 scx_cmask_nr_used_words(const struct scx_cmask *m) +{ + if (!m->nr_cids) + return 0; + return ((m->base & 63) + m->nr_cids - 1) / 64 + 1; +} + +/** + * scx_cmask_for_each_cid - iterate set cids in @m + * @cid: s32 loop var that receives each set cid in turn + * @m: cmask to iterate + * + * Visits set bits within @m's active range in ascending order. Scans only the + * words the active range spans, where head and tail padding is kept zero, so + * no per-cid range check is needed. + */ +#define scx_cmask_for_each_cid(cid, m) \ + for (u64 __bs = (m)->base & ~63u, __wi = 0, \ + __nw = scx_cmask_nr_used_words(m); \ + __wi < __nw; __wi++) \ + for (u64 __w = READ_ONCE((m)->bits[__wi]); \ + __w && ((cid) = __bs + __wi * 64 + __ffs64(__w), true); \ + __w &= __w - 1) + #endif /* _KERNEL_SCHED_EXT_CID_H */ -- 2.54.0