From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sg-1-102.ptr.blmpb.com (sg-1-102.ptr.blmpb.com [118.26.132.102]) (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 4DB903BF307 for ; Tue, 20 Jan 2026 10:40:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=118.26.132.102 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768905628; cv=none; b=gG6ckitPt2qlLm9iwbTmhPtjUbptBUA1s8cOz0xbgZ4A7/pH9GftDDg5Xt549jtet1zfKhq6OttLQKS4Vlloh6/MUqOaTE6qwNNZT3eXyWraqEPHV1eqSBos/6AJQ1DDSlw6w0+IlaSFEHrOyfwn7dTPPF16K1v7v4JomZtcZ1Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768905628; c=relaxed/simple; bh=Y8w4+BdTy001uShPE7SVF7VvvXq4NVGP8qWYzo9Nwiw=; h=Content-Type:From:Date:Mime-Version:References:In-Reply-To: Message-Id:To:Subject:Cc; b=qCskT/F0JprqLUYgUtUyFhUmUxHNvuWxu0KwdYrw/jljQfJBbvI2bRexfK1V7etpfA+Qv9iz2Pv8RyjwkSQnhkF71aIR6svuhsnhqrAFVD/r8+/N+mVawWX5U9CGe7MK7ubtqIgqSdbcW8VCcfa3xTWZ5jiv8vwRmXqjttkfepU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com; spf=pass smtp.mailfrom=bytedance.com; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b=nwjJgEYI; arc=none smtp.client-ip=118.26.132.102 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bytedance.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="nwjJgEYI" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=2212171451; d=bytedance.com; t=1768905617; h=from:subject: mime-version:from:date:message-id:subject:to:cc:reply-to:content-type: mime-version:in-reply-to:message-id; bh=Y8w4+BdTy001uShPE7SVF7VvvXq4NVGP8qWYzo9Nwiw=; b=nwjJgEYIkR/EkpwgeU678wMUKG59wPyGPfiWUlCFoujwJV2aDy/5f84BDN78CWeanzc3fS g5emaoUJLPpBtpbYS88OMXlBj+LFQFvnABAqpDfZOauOpsf0xI8UKc6HodXS1uVtpxr85c WRpVGefUu5iJJWHJiZ3ymjotP9OoKsEJBAcluGOUuBtaKgCLQNf1kp/2ZPoL28XLKv97W1 SzC6SWfh3UQdMyn9b64Ei/zpUloRy0XvBfnGHLxElp8gVYMEdNDUyhumzdTqYNlcLCQ7l7 MC1n58xwMYRCpY80s3iVTIgjAilY4v3vhbsR+R0SF+1yTtZg1/oVtR1GngYhdQ== Content-Type: text/plain; charset=UTF-8 From: "Li Zhe" Date: Tue, 20 Jan 2026 18:39:48 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Original-From: Li Zhe References: <20260120094744.5d92e34a@pumpkin> In-Reply-To: <20260120094744.5d92e34a@pumpkin> X-Mailer: git-send-email 2.45.2 Message-Id: <20260120103949.7673-1-lizhe.67@bytedance.com> To: Subject: Re: [PATCH v2 0/8] Introduce a huge-page pre-zeroing mechanism Content-Transfer-Encoding: quoted-printable X-Lms-Return-Path: Cc: , , , , , , , , , , , , , , , , , , , On Tue, 20 Jan 2026 09:47:44 +0000, david.laight.linux@gmail.com wrote: > On Tue, 20 Jan 2026 14:27:06 +0800 > "Li Zhe" wrote: >=20 > > In light of the preceding discussion, we appear to have reached the > > following understanding: > >=20 > > (1) At present we prefer to mitigate slow application startup (e.g., > > VM creation) by zeroing huge pages at the moment they are freed > > (init_on_free). The principal benefit is that user space gains the > > performance improvement without deploying any additional user space > > daemon. >=20 > Am I missing something? > If userspace does: > $ program_a; program_b > and pages used by program_a are zeroed when it exits you get the delay > for zeroing all the pages it used before program_b starts. > OTOH if the zeroing is deferred program_b only needs to zero the pages > it needs to start (and there may be some lurking). Under the init_on-free approach, improving the speed of zeroing may indeed prove necessary. However, I believe we should first reach consensus on adopting =E2=80=9Cinit_on_free=E2=80=9D as the solution to slow application startup = before turning to performance tuning. Thanks, Zhe