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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Subject: Re: [PATCH 02/14] mm/sparse: remove WARN_ONs from (online|offline)_mem_sections() Message-ID: <7056316c-e811-403f-9edf-8ac3c4248dba@lucifer.local> References: <20260317165652.99114-1-david@kernel.org> <20260317165652.99114-3-david@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260317165652.99114-3-david@kernel.org> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 83D5AC0007 X-Stat-Signature: omhgggqagx39jx73gtuk18eu6czfor8p X-Rspam-User: X-HE-Tag: 1773768086-541956 X-HE-Meta: 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 iBSrdtgZ 7jlx+VHXhCyijrQAm1YfdJ+Ui0TkGfQpkVYIPGdlJJWrbzzGLwwKw9EcH54/Y+5ZhXKS5Gc7Q4ZYzrtSO5wZcbFz7PU+Am3K91jAo3dO+H2gBdYxSBeB09AZ0989lkI8QUyPV9iQ/4TIYkTMQ0jLSJHUEGHkGL6WhG+Cbipm6jtkVpoOlGQij2AXUxjH4G/tKLHMB/ooAcFgl+1HmWAdb0catzVukdMZCVv8FADQzjJFKiI4yXvNrxHQ0CHcbBiY2iU6tCGdwbT+D5fqnW2pzaM9uyGJC9olZSUDgX8GaTx5sOzJyTpveyzzfWuWuByF5J6yA Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Mar 17, 2026 at 05:56:40PM +0100, David Hildenbrand (Arm) wrote: > We do not allow offlining of memory with memory holes, and always > hotplug memory without holes. > > Consequently, we cannot end up onlining or offlining memory sections that > have holes (including invalid sections). That's also why these > WARN_ONs never fired. > > Let's remove the WARN_ONs along with the TODO regarding double-checking. > > Signed-off-by: David Hildenbrand (Arm) I'm warning up to your series! (The bad puns may/may not continue) so: Reviewed-by: Lorenzo Stoakes (Oracle) > --- > mm/sparse.c | 17 ++--------------- > 1 file changed, 2 insertions(+), 15 deletions(-) > > diff --git a/mm/sparse.c b/mm/sparse.c > index dfabe554adf8..93252112860e 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -638,13 +638,8 @@ void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn) > > for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { > unsigned long section_nr = pfn_to_section_nr(pfn); > - struct mem_section *ms; > - > - /* onlining code should never touch invalid ranges */ > - if (WARN_ON(!valid_section_nr(section_nr))) > - continue; > + struct mem_section *ms = __nr_to_section(section_nr); > > - ms = __nr_to_section(section_nr); > ms->section_mem_map |= SECTION_IS_ONLINE; > } > } > @@ -656,16 +651,8 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn) > > for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { > unsigned long section_nr = pfn_to_section_nr(pfn); > - struct mem_section *ms; > + struct mem_section *ms = __nr_to_section(section_nr); > > - /* > - * TODO this needs some double checking. Offlining code makes > - * sure to check pfn_valid but those checks might be just bogus > - */ > - if (WARN_ON(!valid_section_nr(section_nr))) > - continue; > - > - ms = __nr_to_section(section_nr); > ms->section_mem_map &= ~SECTION_IS_ONLINE; > } > } > -- > 2.43.0 >