From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf1-f49.google.com (mail-lf1-f49.google.com [209.85.167.49]) (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 E28F33644D7 for ; Wed, 22 Apr 2026 19:15:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776885355; cv=none; b=itywoF46UX9jkMngWq/jeh5WRMxdx042tO06Dcc887qhZaicDrW0/NTQMik88BgWJqrpiMUf/d9tvYe0Ap/Oikj5CF6jbdCI6xroHr+D2UIVFE8LCxByn1nuprMKMVYC72u+KMWkdC0IEyoNRZAejHs0Vaz2PP7mZc4r82vNr60= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776885355; c=relaxed/simple; bh=reC/3ktwHEf36qZ7CG487Kj9SdhWMZhQYhjyucWyCQY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mW7xtOqJa/CNnIw5IUtyX3a3rh+nzs0DDJHHH+j8QM/KC6vWA0OffZr4xu/X0z7Dxtx4z4Xa6pqkWj9aSo7SAMpSRLsrl8tTov6YaYvccfcrTib4Iw1xWVrbFB1dkFaSoQUnea5Ksy6eS0c2fUJJyuDB01nmvbVRMMMb0TT02IY= 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=YD6A1drZ; arc=none smtp.client-ip=209.85.167.49 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="YD6A1drZ" Received: by mail-lf1-f49.google.com with SMTP id 2adb3069b0e04-5a4113ab355so6119675e87.1 for ; Wed, 22 Apr 2026 12:15:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776885345; x=1777490145; darn=vger.kernel.org; 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=oY7nrdeX7te85EQwTW8KDmLXz64uBX36qr+ohigMp9c=; b=YD6A1drZb461Wf+hVYOMhSj1NbzCLDL/mA5+eJ+GHJXyx4zKrzie0g6/j8tqVOSSGE /bzpqjDDaJ0ccXYnFLBLRQSje9F7pPxklUjYFTyFeUJNvAbk2YzKnCb91zZEl79qVY7w IFMI2l+Rg0I1x/0FPHTPjJyX0qmvF6RHypKE6YauqRKggFVjlZhcKXbdlbSLmeitG9zl kJP1fJ4C5diqVaoZZss5bu7RZIZQHQPtVJmqqdhqWU6H0rlN3uKbbTJFWdGaOzuqO/09 c6WWkpZnqlST5fEY7YivSL1cjvXMfXzdZV9MW90dMyj0rNn8aKD/kRrKD/3qwuHhOYEY oEyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776885345; x=1777490145; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=oY7nrdeX7te85EQwTW8KDmLXz64uBX36qr+ohigMp9c=; b=h+AFz/uB8xD7YezJNqzweQIzUrldyM/dq05LMWPtEjeVXmuT3IB1aT5tAujji6LGx5 V9ZAMDztaoxAhsSy1n5cTjhiN1/BZe62mQ72EBfJByB57tHQHM3GTloPfxg93qMhOhTV wPaKgPV50IIvjj0TLIRCyJNsWal1U90TNDTHe8Chab0gBJ/fX1+cWJMbQRnV8M0l3mLp NbNvjbhnLwBAD+gWN5LibSjMo5ejfS7e6mjv71ZLzEJPT34qhLdB7UKUUNmW+9EXuQXa s/M4eu8Ej3fXRnRzNnHKVUWXgROHjN9S7H78aUAW7Cq/RMASe3zozq9pWkU+/e6u6i5R micA== X-Forwarded-Encrypted: i=1; AFNElJ/s5rE+cxQg8TmfHwXZPRgn4LmUxMzAGvZusKl3ZAJRyArjCYq0g1/P9r4g2O949IsifOXXSayj7YWg0w13@vger.kernel.org X-Gm-Message-State: AOJu0Yz3y5Bc2BfJvkV89etcPbRjyFo31IGeJpqm7EfJ1CEOcNS7YC4V g5UNHi47quvJYVilpq3+q4ZPQOgnfG8+pEdzr3fRzVWLYm6EK9RopnI= X-Gm-Gg: AeBDievKxyBFGHo/peNb/tAeiG3sEBYVOLMi7lLv9pViXC7nBl2ojPZSDIqEX7DJS4r QWMMFsOq7CF8lnvq+xa16WAKfPvfUk6SsRG++UDrFtnS5qutwg5Wr8cHrTtF/+c7PgmYQyfTeKZ /av6cMb0+0R6p/f8Ddzq4b2y+qTchU/553xgpoGv5k5Vvjc20FTzGteia2OZn4yb6myue8HRP06 aIrh2a99diyL2A9yU/3y3d/BP3NSSYwSczfBMf5/qn8FtKE8yyanFAuElYlRTFHpy+Iahj5wv1k 93ulcTBxAuNBq18gTwPtjoMbVbeLbogYGRy+7CaIQ4Ubaa/4k3gD+0vgkfmeDFkknH3vJj1v/l9 XEIGhoMSc1p4vONY/PKveQLb4fWLIZSQpL7u0mw9O/i6RePyTynrTlusXCu2jkUh674Z3q7Fwgr Dji27mVIuJHMSSEMfotaVtUw== X-Received: by 2002:a05:6512:a90:b0:5a4:d4:5c5e with SMTP id 2adb3069b0e04-5a4172dc775mr6123332e87.22.1776885345324; Wed, 22 Apr 2026 12:15:45 -0700 (PDT) Received: from p183 ([178.172.147.87]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5a4185ad108sm4640295e87.3.2026.04.22.12.15.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Apr 2026 12:15:45 -0700 (PDT) From: Alexey Dobriyan To: akpm@linux-foundation.org Cc: adobriyan@gmail.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, ebiederm@xmission.com Subject: [PATCH 2/2] proc: rewrite next_tgid() Date: Wed, 22 Apr 2026 22:17:45 +0300 Message-ID: <20260422191745.435556-2-adobriyan@gmail.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260422191745.435556-1-adobriyan@gmail.com> References: <20260422191745.435556-1-adobriyan@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit * deduplicate "iter.tgid += 1" line, Right now it is done once inside next_tgid() itself and second time inside "for" loop. * deduplicate next_tgid() call itself with different loop style: auto it = make_tgid_iter(); while (next_tgid(&it)) { ... } gcc seems to inline it twice: $ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux add/remove: 0/1 grow/shrink: 1/0 up/down: 100/-245 (-145) Function old new delta proc_pid_readdir 531 631 +100 next_tgid 245 - -245 * make tgid_iter.pid_ns const it never changes during readdir anyway Signed-off-by: Alexey Dobriyan --- fs/proc/base.c | 57 +++++++++++++++++++++++++++++--------------------- 1 file changed, 33 insertions(+), 24 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index f2db455dbbfd..f38ac943ec32 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3543,30 +3543,43 @@ struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags) struct tgid_iter { unsigned int tgid; struct task_struct *task; - struct pid_namespace *pid_ns; + struct pid_namespace *const pid_ns; }; -static struct tgid_iter next_tgid(struct tgid_iter iter) +static +struct tgid_iter +make_tgid_iter(unsigned int init_tgid, struct pid_namespace *pid_ns) { - struct pid *pid; + return (struct tgid_iter){ + .tgid = init_tgid - 1, + .pid_ns = pid_ns, + }; +} + +static bool next_tgid(struct tgid_iter *it) +{ + if (it->task) { + put_task_struct(it->task); + it->task = NULL; + } - if (iter.task) - put_task_struct(iter.task); rcu_read_lock(); -retry: - iter.task = NULL; - pid = find_ge_pid(iter.tgid, iter.pid_ns); - if (pid) { - iter.tgid = pid_nr_ns(pid, iter.pid_ns); - iter.task = pid_task(pid, PIDTYPE_TGID); - if (!iter.task) { - iter.tgid += 1; - goto retry; + while (1) { + it->tgid += 1; + const auto pid = find_ge_pid(it->tgid, it->pid_ns); + if (pid) { + it->tgid = pid_nr_ns(pid, it->pid_ns); + it->task = pid_task(pid, PIDTYPE_TGID); + if (it->task) { + get_task_struct(it->task); + rcu_read_unlock(); + return true; + } + } else { + rcu_read_unlock(); + return false; } - get_task_struct(iter.task); } - rcu_read_unlock(); - return iter; } #define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2) @@ -3574,7 +3587,6 @@ static struct tgid_iter next_tgid(struct tgid_iter iter) /* for the /proc/ directory itself, after non-process stuff has been done */ int proc_pid_readdir(struct file *file, struct dir_context *ctx) { - struct tgid_iter iter; struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb); struct pid_namespace *pid_ns = proc_pid_ns(file_inode(file)->i_sb); loff_t pos = ctx->pos; @@ -3592,12 +3604,9 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx) return 0; ctx->pos = pos = pos + 1; } - iter.tgid = pos - TGID_OFFSET; - iter.task = NULL; - iter.pid_ns = pid_ns; - for (iter = next_tgid(iter); - iter.task; - iter.tgid += 1, iter = next_tgid(iter)) { + + auto iter = make_tgid_iter(pos - TGID_OFFSET, pid_ns); + while (next_tgid(&iter)) { char name[10 + 1]; unsigned int len; -- 2.52.0