From nobody Sun Feb 8 10:03:44 2026 Received: from mail-pf1-f171.google.com (mail-pf1-f171.google.com [209.85.210.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3C87C33DEDF for ; Thu, 18 Dec 2025 13:02:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766062961; cv=none; b=gMnrW+iDE0l0E8s6/tlN3esTUu9qYx9A1UbwZcAzum6G04sgzqN1GEo5WNgZRdb7bMxSJsfSK9qfsMSoi9AXM+GQaz83CQolHCARZKNbAYommFdyViEm1bJRJYUqPWskZY+qahzQCiDhuicBzNcGOkLpC3qdmDkb2TKRz3BzPfg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766062961; c=relaxed/simple; bh=yg6WGaiQYlWxGEnLnaXGhHCm+obJHKWs9xeQnqsgwzM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=P5bzakz9jEDH1PbKo34XOBx4++/vmIOVP2XkMH5xACzj3MKlEkH41/acNLA4Zpyrn4tzYI+A0xHeP+fglUMTMdmCRZcoN8wNSM/cU/24uQ+nGogBqMHRQtypfBUx4554KDx8eL+YVIW/EheJAgDOrPK7Q9B+J5k3bFFxwq96roU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=S0yFkvKI; arc=none smtp.client-ip=209.85.210.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="S0yFkvKI" Received: by mail-pf1-f171.google.com with SMTP id d2e1a72fcca58-7aa9be9f03aso568673b3a.2 for ; Thu, 18 Dec 2025 05:02:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1766062955; x=1766667755; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=shW5tMP8WEpK+xDNfp+4rDEESWFd1Aot2MN3bptvApc=; b=S0yFkvKIadcnWQMiVW+BAQUhNa5btRMYa/SZ7MuEQ9tUhQGsF+HAre32lv5NI66aUm edb+jRaSabXFRO5RRs2iGlq0e/ZJl/TqgoLg9VOojCNqbr6+73Af7g1lXTVYvLxJwDo2 bKjehPhr9vsxJgQrIflFfCyQ/BxZ+C1v4S7J2XgwESSc0E2Dp2iCnKTbLuku5FciWx59 Bjjj6hzjhYtvJxXP8ZxhDeuaRmjWm0Shi4Woudj49ObsnLHtys8nkSJJQr4ondAoMtab 0EWTwK30JrwoOEuuDmyLFbhVNW4rpGWv7IoeR87XogvyTCZ7k7ZyPzVwqqrHjszv/aMt HEdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1766062955; x=1766667755; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=shW5tMP8WEpK+xDNfp+4rDEESWFd1Aot2MN3bptvApc=; b=suz8+7a4Fnx8Zb5ACkuL/eqJia8y0+mzCmiL60EUvKr1qQ+N2AQJTitbUfCY9El4Xw GkLwVQ8NpnFeUZJcU+2+UcX1iJWC+vg74/G72lhRjyityZ+edu+iyD+WFL/47+91muCb R+JTtKjVPkGWQz8eZbGynKVAtL1FWKyy+adz6ZQPnTiaOzRdueoM4eWZH4EEzLWGyijk tZHgryNu1mlX4o8YxQ85s9k4uH0uACkP2TNIatSVWVNyYHTLh+xabiPQFbOI8WTxroT9 GWbwLMpD3HjyvUp5MzvcFn5yyRMlszJ+iW2R62k0ZXdMFeTvyvwM+78iEpaqRlJqqtP+ dJcw== X-Gm-Message-State: AOJu0Yzb1/kCeA1IxrG3DwdiicILU0pl4yzPZ7qS6VkiXkEaaQD/fZfQ qBFbwcNARy+OsbpoPY+//tny/yzTAR1erSc/ECqz69oI+CM1r/IC39JIpy8t/CdK X-Gm-Gg: AY/fxX6loeEGlAX6QVCTQB/sAfFXokNaSB2DCZitE7UHvh4CA9e4QBnKDWVXzZpRtJ2 pEDYvfKa1GgKBUitTEDaEISOjy4csdczeFcofhWbYemHF/9P5WwiFGOLDpIuB+mZhITj/nCpZ8x pLvUxSZ6M6sDQD1dt0uSylK1EwZ+6/rmrsSddhpaXXKf5BpBIGrdAfe74rYVYwqvEU5IlqbYI7l YoUlto5D7HtyIDeYmmGOVOqCYH4JNo/BDn+6FnzRBGA0G/7b7SFntka94NUhGN1fm+eWDadB7eg qENBHe7y8ySqCYeZtCy7APn7iJXMuotvSN1iL+OWcaVk9Fpzc/n+M39pod5a1w5mKT3dKvhr7Ow 1wglEEMUKsYnvgdflkWoS2HXJkQqckjs0uhOZti6dqAOsd524tt1i4D5txH3/aRd9LxEKQCuTCV 33jZcwqxs98gYMosVCXqnBgmLs X-Google-Smtp-Source: AGHT+IExIFYvb3Ll74DtqQGkHUifcaAZGhfwHkiWeI1ZI7bdl9sBGAe2neWX2mKxOqBe8zEfw9NuqA== X-Received: by 2002:a05:6a21:99aa:b0:35d:be42:92de with SMTP id adf61e73a8af0-369ad9d5895mr21398086637.21.1766062955370; Thu, 18 Dec 2025 05:02:35 -0800 (PST) Received: from DESKTOP-MOQC9AF.mioffice.cn ([43.224.245.233]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c1d2d9ae134sm2303448a12.1.2025.12.18.05.02.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Dec 2025 05:02:34 -0800 (PST) From: Zhan Xusheng X-Google-Original-From: Zhan Xusheng To: linux-kernel@vger.kernel.org Cc: shkaushik@amperecomputing.com, Zhan Xusheng Subject: [PATCH v2] sched/fair: factor out common sched_entity stats/task lookup Date: Thu, 18 Dec 2025 21:02:11 +0800 Message-ID: <20251218130211.32785-1-zhanxusheng@xiaomi.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Several fair scheduler helpers (update_stats_*_fair()) repeat the same boilerplate code to retrieve sched_statistics and the associated task (if any) from a sched_entity. This patch factors that common logic into a single small helper: static __always_inline void get_se_stats_and_task(...) The helper reduces code duplication and improves readability without changing behavior or control flow. Based on feedback from Shubhang Kaushik Prasanna Kumar (), we changed the helper from inline to __always_inline to guarantee inlining in critical hot paths and avoid any potential overhead. Although the helper takes addresses of local variables (&stats, &p), assembly comparison for enqueue_task_fair() before/after this patch shows no additional loads, spills, or function calls: mov: 187 vs 187 add: 13 vs 13 lea: 22 vs 22 call: 20 vs 20 push: 6 vs 6 pop: 12 vs 12 This confirms that compiler optimizations are preserved and no performance regression is expected in these hot paths. Signed-off-by: Zhan Xusheng --- kernel/sched/fair.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index da46c3164537..bee30bfca6e5 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1243,6 +1243,15 @@ static void update_curr_fair(struct rq *rq) update_curr(cfs_rq_of(&rq->donor->se)); } =20 +static __always_inline +void get_se_stats_and_task(struct sched_entity *se, + struct sched_statistics **stats, + struct task_struct **p) +{ + *stats =3D __schedstats_from_se(se); + *p =3D entity_is_task(se) ? task_of(se) : NULL; +} + static inline void update_stats_wait_start_fair(struct cfs_rq *cfs_rq, struct sched_entity *s= e) { @@ -1252,10 +1261,7 @@ update_stats_wait_start_fair(struct cfs_rq *cfs_rq, = struct sched_entity *se) if (!schedstat_enabled()) return; =20 - stats =3D __schedstats_from_se(se); - - if (entity_is_task(se)) - p =3D task_of(se); + get_se_stats_and_task(se, &stats, &p); =20 __update_stats_wait_start(rq_of(cfs_rq), p, stats); } @@ -1269,7 +1275,7 @@ update_stats_wait_end_fair(struct cfs_rq *cfs_rq, str= uct sched_entity *se) if (!schedstat_enabled()) return; =20 - stats =3D __schedstats_from_se(se); + get_se_stats_and_task(se, &stats, &p); =20 /* * When the sched_schedstat changes from 0 to 1, some sched se @@ -1280,9 +1286,6 @@ update_stats_wait_end_fair(struct cfs_rq *cfs_rq, str= uct sched_entity *se) if (unlikely(!schedstat_val(stats->wait_start))) return; =20 - if (entity_is_task(se)) - p =3D task_of(se); - __update_stats_wait_end(rq_of(cfs_rq), p, stats); } =20 @@ -1295,10 +1298,7 @@ update_stats_enqueue_sleeper_fair(struct cfs_rq *cfs= _rq, struct sched_entity *se if (!schedstat_enabled()) return; =20 - stats =3D __schedstats_from_se(se); - - if (entity_is_task(se)) - tsk =3D task_of(se); + get_se_stats_and_task(se, &stats, &tsk); =20 __update_stats_enqueue_sleeper(rq_of(cfs_rq), tsk, stats); } --=20 2.43.0