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b=GSsf3AHsu9HSL2zagjPF2vAc+Fn16ULqmVlE4aK3n1ZtU1MRzfxXt1BfMmgJYJg9h OeGoWxLiB3NzysWXngOnJRx6LML8YWteJDEy/H5oAz4Xv1vuPdHBhv7BCj6RUg9YTo HEWbi/o5BdEjqcLggfg+7uX7+pE+oN/MXqad966PkVTGuPRAvgP+KyGis01nCJswDT VpT66ikYzckXnQFJiZOEjhfMmddYYPti5NP5hqyPPAda5oCTipX5bzmTQhOS4HkRHn aSv+ihiYh4GXNxxhc7KbgNsuYTqF5tbVmKfc+BaU/8KOxhtOHh/LX9zrOfY6RXA5PA 75le3IEYnh66w== Date: Tue, 1 Sep 2026 09:27:54 +0300 From: Mike Rapoport To: Sang-Heon Jeon Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm/mm_init: remove zone_absent_pages_in_node() Message-ID: References: <20260827144151.486192-1-ekffu200098@gmail.com> <178816183737.3691663.7482057515031348878.b4-review@b4> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 122BB1C0006 X-Stat-Signature: xfi9wmr3umin1y4hpdobj3fr47r1j93a X-HE-Tag: 1788244080-618957 X-HE-Meta: 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 dVJybkGh tjystTgsuTXjWRJlwMGjQJDN96z8YZFm54J1OMoedB6I7wm849+YcgyYMVUaXWiyxk0x9HDQVjj8/Qe1myHccWXbJRegVLWDYy4hkdxX0UNVixyN6mhsgWv3M1XQ1SZAjz2L9hYFPWMRVanMcMm41/NiKdUff2+S2cnRt9ltDjzZbRAlbOEGPT/8d5ehcZwrUMRSwm6/sw4qJEjgyEHgqXVTuNutu6z+SgL6I87NwMBQxmIpTMPoFkXBsrktFtmHbHjByRXDxfTFtPyAlqi6jta9DZ4Hp/KpPxzBFThPq8iIFi3rWA0kc9pulDp9v3wVQtKEIxb5PheyL/0JP9YMYL2yccLUJIJ7Lmd9w Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Aug 31, 2026 at 08:30:40PM +0900, Sang-Heon Jeon wrote: > Hi, > > On Mon, Aug 31, 2026 at 4:37 PM Mike Rapoport wrote: > > > > > zone_absent_pages_in_node() returns 0 when the zone is empty and > > > otherwise calls __absent_pages_in_range(), which already returns 0 for > > > an empty range. > > > > Right, but it loops over memblock memory for an empty zone to get that 0 > > Indeed. How about adding an early return in __absent_pages_in_range() > to avoid unnecessary iteration? I just want to remove the wrapper, > which never uses its zone_type argument since eb0e5b61369f > ("mm/mm_init: don't overlap NORMAL and MOVABLE zones with > kernelcore=mirror") > > unsigned long nr_absent = range_end_pfn - range_start_pfn; > unsigned long start_pfn, end_pfn; > int i; > > + if (!nr_absent) Yes, just please add a comment: /* range is empty, nothing to do */ > + return 0; > + > for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) { > start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn); > end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn); > > > -- > > Sincerely yours, > > Mike. > > -- Sincerely yours, Mike.