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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Subject: Re: [PATCH 08/14] mm/sparse: remove sparse_decode_mem_map() Message-ID: <8af7c994-14ac-4c9f-8c27-b35969440d80@lucifer.local> References: <20260317165652.99114-1-david@kernel.org> <20260317165652.99114-9-david@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260317165652.99114-9-david@kernel.org> X-Rspamd-Queue-Id: F2BAF8000B X-Stat-Signature: nirrmgc3uqktyr71pm4z97m6fgxc3kjs X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1773775554-608502 X-HE-Meta: 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 4lAw6BaK ak2lZZ8/bLCotpW7ZHjbkanP+mnGke3VAmfoC8CMn24TTkSi80uHfkoJdLyjQcyLWbrvjy/3WaNmQU+E/Em1H/qBVoBy3yBSRzNU/fIUxb9ixn0mVM57/UwG1G5CRknYcqb7jIswiYTMl6p8wsOxoanSpitCggkZ1THlozaLXplCS1VUQejcsXeBwG/sZEHYCAW6pknR9VU0A9tXdCHkTv/DWiKvryNq8WNtapHbTL4MOJxm20HhupYhHtXiXW3U88p65bcrFOOKSTeGsQuejH/WrQm/R+x13vheO 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 05:56:46PM +0100, David Hildenbrand (Arm) wrote: > section_deactivate() applies to CONFIG_SPARSEMEM_VMEMMAP only. So we can > just use pfn_to_page() (after making sure we have the start PFN of the > section), and remove sparse_decode_mem_map(). > > Signed-off-by: David Hildenbrand (Arm) it's more like pfn_to_patch(), so that's a: Reviewed-by: Lorenzo Stoakes (Oracle) >From me! > --- > include/linux/memory_hotplug.h | 2 -- > mm/sparse.c | 16 +--------------- > 2 files changed, 1 insertion(+), 17 deletions(-) > > diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h > index e77ef3d7ff73..815e908c4135 100644 > --- a/include/linux/memory_hotplug.h > +++ b/include/linux/memory_hotplug.h > @@ -308,8 +308,6 @@ extern int sparse_add_section(int nid, unsigned long pfn, > struct dev_pagemap *pgmap); > extern void sparse_remove_section(unsigned long pfn, unsigned long nr_pages, > struct vmem_altmap *altmap); > -extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map, > - unsigned long pnum); > extern struct zone *zone_for_pfn_range(enum mmop online_type, > int nid, struct memory_group *group, unsigned long start_pfn, > unsigned long nr_pages); > diff --git a/mm/sparse.c b/mm/sparse.c > index 636a4a0f1199..2a1f662245bc 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -274,18 +274,6 @@ static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long p > return coded_mem_map; > } > > -#ifdef CONFIG_MEMORY_HOTPLUG > -/* > - * Decode mem_map from the coded memmap > - */ > -struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum) > -{ > - /* mask off the extra low bits of information */ > - coded_mem_map &= SECTION_MAP_MASK; > - return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); > -} > -#endif /* CONFIG_MEMORY_HOTPLUG */ > - > static void __meminit sparse_init_one_section(struct mem_section *ms, > unsigned long pnum, struct page *mem_map, > struct mem_section_usage *usage, unsigned long flags) > @@ -758,8 +746,6 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > > empty = is_subsection_map_empty(ms); > if (empty) { > - unsigned long section_nr = pfn_to_section_nr(pfn); > - > /* > * Mark the section invalid so that valid_section() > * return false. This prevents code from dereferencing > @@ -778,7 +764,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > kfree_rcu(ms->usage, rcu); > WRITE_ONCE(ms->usage, NULL); > } > - memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); > + memmap = pfn_to_page(SECTION_ALIGN_DOWN(pfn)); > } > > /* > -- > 2.43.0 > Cheers, Lorenzo