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b=oYGnh4ATN+hfZHYhpzioYH3mG6rhP2qNcxVvtio3P2HRFtfdKXYIg6j6CrSy4ItTq Rcxf5NV3sqUD7EczsTyU37ixCyH0cvzyO/+ht8mqTNz5pIBdl95pEIEwsHrQeTRXBP Kr/KiBWZm4NX6o4wCOt71ZIcRH6KMBiExDfIVFy4= Date: Wed, 15 Jan 2025 15:42:43 -0800 From: Andrew Morton To: Yuntao Wang Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko Subject: Re: [PATCH] mm/page_alloc: Remove the incorrect and misleading comment Message-Id: <20250115154243.4a31f9fbf805169d2c5594dd@linux-foundation.org> In-Reply-To: <20250115041634.63387-1-yuntao.wang@linux.dev> References: <20250115041634.63387-1-yuntao.wang@linux.dev> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 57EB28000F X-Stat-Signature: 9gabhgjqyqapkciox4azioyp139qz99h X-Rspam-User: X-HE-Tag: 1736984565-101940 X-HE-Meta: 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 e9ytrR0a auCX5X6GI46nSH6AXsZR4Tkj1csZly4/SOS0VriAtRYaE2umEM8SU9UrQQ6EIVYSlA0g2rvphkxoVf5V7pafwLInhJbLogAmcwUnGwWA4v3Gyv/NobElM3k68uL/LOKoUSgleTPNQ+1TC5sd7cv7Hh/rt70fgwazFG6852BP303HAhHCk655pOY7P1yeVi1GeO4f9mnE7AQhidldtC0s+DmuXKHW5GINUN3bnURyu/xpW8VqdMX9QLpcLL4NlSyFwLriQZ5zPafgpIOto7pW/9HLLnGZVLhXCyEiFDMXU+dj9TRo= 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 Wed, 15 Jan 2025 12:16:34 +0800 Yuntao Wang wrote: > The comment removed in this patch originally belonged to the > build_zonelists_in_zone_order() function, which was introduced by commit > f0c0b2b808f2 ("change zonelist order: zonelist order selection logic"). > > Later, commit c9bff3eebc09 ("mm, page_alloc: rip out ZONELIST_ORDER_ZONE") > removed build_zonelists_in_zone_order() but left its comment behind. > > Subsequently, commit 9d3be21bf9c0 ("mm, page_alloc: simplify zonelist > initialization") moved the node_order variable into build_zonelists(), > making the comment originally belonged to build_zonelists_in_zone_order() > appear as if it were part of build_zonelists(). > > ... > > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5161,13 +5161,6 @@ static void build_thisnode_zonelists(pg_data_t *pgdat) > zonerefs->zone_idx = 0; > } > > -/* > - * Build zonelists ordered by zone and nodes within zones. > - * This results in conserving DMA zone[s] until all Normal memory is > - * exhausted, but results in overflowing to remote node while memory > - * may still exist in local DMA zone. > - */ > - Yes, it's not obvious which code this comment is telling us about. I do wonder if the information in this comment could be updated and moved somewhere more appropriate, rather than simply removing it. Oh well, not very important.