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charset=us-ascii Content-Disposition: inline In-Reply-To: <20200206135016.GA25537@MiWiFi-R3L-srv> User-Agent: NeoMutt/20170113 (1.7.2) 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: On Thu, Feb 06, 2020 at 09:50:16PM +0800, Baoquan He wrote: >On 02/06/20 at 02:28pm, David Hildenbrand wrote: >> On 06.02.20 13:53, Wei Yang wrote: >> > When we use SPARSEMEM instead of SPARSEMEM_VMEMMAP, pfn_to_page() >> > doesn't work before sparse_init_one_section() is called. This leads to a >> > crash when hotplug memory. >> > >> > We should use memmap as it did. >> > >> > Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") >> > Signed-off-by: Wei Yang >> > CC: Dan Williams >> > --- >> > mm/sparse.c | 2 +- >> > 1 file changed, 1 insertion(+), 1 deletion(-) >> > >> > diff --git a/mm/sparse.c b/mm/sparse.c >> > index 5a8599041a2a..2efb24ff8f96 100644 >> > --- a/mm/sparse.c >> > +++ b/mm/sparse.c >> > @@ -882,7 +882,7 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn, >> > * Poison uninitialized struct pages in order to catch invalid flags >> > * combinations. >> > */ >> > - page_init_poison(pfn_to_page(start_pfn), sizeof(struct page) * nr_pages); >> > + page_init_poison(memmap, sizeof(struct page) * nr_pages); >> >> If you add sub-sections that don't fall onto the start of the section, >> >> pfn_to_page(start_pfn) != memmap >> >> and your patch would break that under SPARSEMEM_VMEMMAP if I am not wrong. > >It returns the pfn_to_page(pfn) from __populate_section_memmap() and >assign to memmap in vmemmap case, how come it breaks anything. Correct >me if I was wrong. > Just see your reply. Thanks for your explanation. :-) >> David / dhildenb -- Wei Yang Help you, Help me