From nobody Sat Feb 7 19:08:33 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5970E30DD00 for ; Mon, 15 Dec 2025 20:15:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765829719; cv=none; b=F/A8SL3uyOCti7qaEl1j4URCUeJGw2pPRtcJHyIxuL6Ay1egqIl4U9nvMqX7ppc0R9iRM0HEnwpUmd0Hbf8tSbPY7FuyWjMXHrxonzjuw45Xfg2UL799BMIwTprw3d85QDnYBKgCE8sGLKu32/nzGXggnMoooNZzdPLgFcq2I5g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765829719; c=relaxed/simple; bh=lndhGxntE8LxLLD3QKPIqsHLHmRXP5EULzdGjPzuuOo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=RXwxLC7DHcEyB67ivVp8kHHpKe4H1y4MMzGqRbjoQP0vOh41yFjBUuSnvWCyE4aJIIvuyL13L4QyPjjI2aE5OhZhHZFG+Zgmc6EVgaZyL56fcry5aaBNvWgun7TAC/A6yWQ6vQwaVpiT7jlJfp/V6u44t922P5rnuW2bIdFuAk0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mUqNzBOv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mUqNzBOv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F24DC4CEF5; Mon, 15 Dec 2025 20:15:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765829718; bh=lndhGxntE8LxLLD3QKPIqsHLHmRXP5EULzdGjPzuuOo=; h=From:To:Cc:Subject:Date:From; b=mUqNzBOvzKcnRPsrqa6JA64eHuzPJC/vHNm6ZB5O/0WwvvG3fB9gGswu1uSZKLman 1+ucMwxsFPOF7kbVkQ9XPmJHLAWEWG+EyDg7ofOpGHAjZrUiodH4XWJqFa2ehLiF7C x1JaZZZTl2BRA9QUQw0HAHr7gL9gOg36mWwFUC2fglorS/mlfN229OjdUiNZrDq4Gt lG6Fvews53lWjc9Gx0yRRakFEfYg3qFD8Zc2lvtbTbUcM648l1osRuxePBvTWqZuiF ULwcbxRbO2VT9i0eea7Q75FtcXSQ5KvgD7XPW0TUgZ1KaMO70u4C8OqW11RSSh8ogF /6zCLJF+Am8Gg== From: Tycho Andersen To: Christian Brauner , Oleg Nesterov Cc: linux-kernel@vger.kernel.org, "Tycho Andersen (AMD)" Subject: [PATCH] pid: remove unnecessary idr_preload() Date: Mon, 15 Dec 2025 13:15:14 -0700 Message-ID: <20251215201514.1343231-1-tycho@kernel.org> X-Mailer: git-send-email 2.52.0 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" From: "Tycho Andersen (AMD)" As near as I can tell, nothing in the second pidmap_lock critical section actually allocates an id, so there is no need to do idr_preload(). idr_replace() does not, nor does pidfs_add_pid(). I boot tested this and built a kernel on a $large core system, so hopefully that would have caught any errors. Signed-off-by: Tycho Andersen (AMD) --- kernel/pid.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/kernel/pid.c b/kernel/pid.c index a31771bc89c1..b0fefeb0a1ec 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -270,7 +270,6 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *= set_tid, INIT_HLIST_HEAD(&pid->inodes); =20 upid =3D pid->numbers + ns->level; - idr_preload(GFP_KERNEL); spin_lock(&pidmap_lock); if (!(ns->pid_allocated & PIDNS_ADDING)) goto out_unlock; @@ -281,14 +280,12 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t= *set_tid, upid->ns->pid_allocated++; } spin_unlock(&pidmap_lock); - idr_preload_end(); ns_ref_active_get(ns); =20 return pid; =20 out_unlock: spin_unlock(&pidmap_lock); - idr_preload_end(); put_pid_ns(ns); =20 out_free: base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8 --=20 2.52.0