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charset=UTF-8 From: "Li Zhe" Subject: Re: [PATCH v2 0/8] Introduce a huge-page pre-zeroing mechanism X-Mailer: git-send-email 2.45.2 Cc: , , , , , , , , , , , , , , , , , , , Date: Tue, 20 Jan 2026 18:39:48 +0800 To: X-Lms-Return-Path: References: <20260120094744.5d92e34a@pumpkin> Mime-Version: 1.0 X-Original-From: Li Zhe X-Stat-Signature: d8mqaw5qijauk5g6uzb5gd54yxxcm1kq X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: AE811180009 X-Rspam-User: X-HE-Tag: 1768905625-621547 X-HE-Meta: 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 fhQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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