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Mon, 09 Mar 2020 05:00:44 -0400 X-MC-Unique: -AK_XTlCO_ushKVhLG7THA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B82B78010E7; Mon, 9 Mar 2020 09:00:42 +0000 (UTC) Received: from [10.36.118.32] (unknown [10.36.118.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id 467B362667; Mon, 9 Mar 2020 09:00:39 +0000 (UTC) Subject: Re: [PATCH v3 4/7] mm/sparse.c: only use subsection map in VMEMMAP case To: Baoquan He , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@suse.com, richardw.yang@linux.intel.com, dan.j.williams@intel.com, osalvador@suse.de, rppt@linux.ibm.com References: <20200307084229.28251-1-bhe@redhat.com> <20200307084229.28251-5-bhe@redhat.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMFCQlmAYAGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl3pImkCGQEACgkQTd4Q 9wD/g1o+VA//SFvIHUAvul05u6wKv/pIR6aICPdpF9EIgEU448g+7FfDgQwcEny1pbEzAmiw zAXIQ9H0NZh96lcq+yDLtONnXk/bEYWHHUA014A1wqcYNRY8RvY1+eVHb0uu0KYQoXkzvu+s Dncuguk470XPnscL27hs8PgOP6QjG4jt75K2LfZ0eAqTOUCZTJxA8A7E9+XTYuU0hs7QVrWJ jQdFxQbRMrYz7uP8KmTK9/Cnvqehgl4EzyRaZppshruKMeyheBgvgJd5On1wWq4ZUV5PFM4x II3QbD3EJfWbaJMR55jI9dMFa+vK7MFz3rhWOkEx/QR959lfdRSTXdxs8V3zDvChcmRVGN8U Vo93d1YNtWnA9w6oCW1dnDZ4kgQZZSBIjp6iHcA08apzh7DPi08jL7M9UQByeYGr8KuR4i6e RZI6xhlZerUScVzn35ONwOC91VdYiQgjemiVLq1WDDZ3B7DIzUZ4RQTOaIWdtXBWb8zWakt/ ztGhsx0e39Gvt3391O1PgcA7ilhvqrBPemJrlb9xSPPRbaNAW39P8ws/UJnzSJqnHMVxbRZC Am4add/SM+OCP0w3xYss1jy9T+XdZa0lhUvJfLy7tNcjVG/sxkBXOaSC24MFPuwnoC9WvCVQ ZBxouph3kqc4Dt5X1EeXVLeba+466P1fe1rC8MbcwDkoUo65Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAiUEGAECAA8FAlXLn5ECGwwFCQlmAYAACgkQTd4Q 9wD/g1qA6w/+M+ggFv+JdVsz5+ZIc6MSyGUozASX+bmIuPeIecc9UsFRatc91LuJCKMkD9Uv GOcWSeFpLrSGRQ1Z7EMzFVU//qVs6uzhsNk0RYMyS0B6oloW3FpyQ+zOVylFWQCzoyyf227y GW8HnXunJSC+4PtlL2AY4yZjAVAPLK2l6mhgClVXTQ/S7cBoTQKP+jvVJOoYkpnFxWE9pn4t H5QIFk7Ip8TKr5k3fXVWk4lnUi9MTF/5L/mWqdyIO1s7cjharQCstfWCzWrVeVctpVoDfJWp 4LwTuQ5yEM2KcPeElLg5fR7WB2zH97oI6/Ko2DlovmfQqXh9xWozQt0iGy5tWzh6I0JrlcxJ ileZWLccC4XKD1037Hy2FLAjzfoWgwBLA6ULu0exOOdIa58H4PsXtkFPrUF980EEibUp0zFz GotRVekFAceUaRvAj7dh76cToeZkfsjAvBVb4COXuhgX6N4pofgNkW2AtgYu1nUsPAo+NftU CxrhjHtLn4QEBpkbErnXQyMjHpIatlYGutVMS91XTQXYydCh5crMPs7hYVsvnmGHIaB9ZMfB njnuI31KBiLUks+paRkHQlFcgS2N3gkRBzH7xSZ+t7Re3jvXdXEzKBbQ+dC3lpJB0wPnyMcX FOTT3aZT7IgePkt5iC/BKBk3hqKteTnJFeVIT7EC+a6YUFg= Organization: Red Hat GmbH Message-ID: Date: Mon, 9 Mar 2020 10:00:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200307084229.28251-5-bhe@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07.03.20 09:42, Baoquan He wrote: > Currently, to support subsection aligned memory region adding for pmem, > subsection map is added to track which subsection is present. > > However, config ZONE_DEVICE depends on SPARSEMEM_VMEMMAP. It means > subsection map only makes sense when SPARSEMEM_VMEMMAP enabled. For the > classic sparse, subsection map is meaningless and confusing. > > About the classic sparse which doesn't support subsection hotplug, Dan > said it's more because the effort and maintenance burden outweighs the > benefit. Besides, the current 64 bit ARCHes all enable > SPARSEMEM_VMEMMAP_ENABLE by default. > > Combining the above reasons, no need to provide subsection map and the > relevant handling for the classic sparse. Handle it with this patch. > > Signed-off-by: Baoquan He > --- > include/linux/mmzone.h | 2 ++ > mm/sparse.c | 25 +++++++++++++++++++++++++ > 2 files changed, 27 insertions(+) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index 42b77d3b68e8..f3f264826423 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -1143,7 +1143,9 @@ static inline unsigned long section_nr_to_pfn(unsigned long sec) > #define SUBSECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SUBSECTION_MASK) > > struct mem_section_usage { > +#ifdef CONFIG_SPARSEMEM_VMEMMAP > DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION); > +#endif > /* See declaration of similar field in struct zone */ > unsigned long pageblock_flags[0]; > }; > diff --git a/mm/sparse.c b/mm/sparse.c > index d9dcd58d5c1d..2142045ab5c5 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -209,6 +209,7 @@ static inline unsigned long first_present_section_nr(void) > return next_present_section_nr(-1); > } > > +#ifdef CONFIG_SPARSEMEM_VMEMMAP > static void subsection_mask_set(unsigned long *map, unsigned long pfn, > unsigned long nr_pages) > { > @@ -243,6 +244,11 @@ void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) > nr_pages -= pfns; > } > } > +#else > +void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) > +{ > +} > +#endif > > /* Record a memory area against a node. */ > void __init memory_present(int nid, unsigned long start, unsigned long end) > @@ -726,6 +732,7 @@ static void free_map_bootmem(struct page *memmap) > } > #endif /* CONFIG_SPARSEMEM_VMEMMAP */ > > +#ifdef CONFIG_SPARSEMEM_VMEMMAP > static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) > { > DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; > @@ -753,6 +760,17 @@ static bool is_subsection_map_empty(struct mem_section *ms) > return bitmap_empty(&ms->usage->subsection_map[0], > SUBSECTIONS_PER_SECTION); > } > +#else > +static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) > +{ > + return 0; > +} > + > +static bool is_subsection_map_empty(struct mem_section *ms) > +{ > + return true; > +} > +#endif > > static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > struct vmem_altmap *altmap) > @@ -809,6 +827,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > ms->section_mem_map = (unsigned long)NULL; > } > > +#ifdef CONFIG_SPARSEMEM_VMEMMAP > static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) > { > struct mem_section *ms = __pfn_to_section(pfn); > @@ -830,6 +849,12 @@ static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) > > return rc; > } > +#else > +static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) > +{ > + return 0; > +} > +#endif > > static struct page * __meminit section_activate(int nid, unsigned long pfn, > unsigned long nr_pages, struct vmem_altmap *altmap) > Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb