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Tue, 11 Feb 2020 14:43:56 +0000 (UTC) Received: from [10.36.117.14] (ovpn-117-14.ams2.redhat.com [10.36.117.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id C485A5DA7B; Tue, 11 Feb 2020 14:43:54 +0000 (UTC) Subject: Re: [PATCH 3/7] 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, dan.j.williams@intel.com, richardw.yang@linux.intel.com References: <20200209104826.3385-1-bhe@redhat.com> <20200209104826.3385-4-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: Tue, 11 Feb 2020 15:43:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200209104826.3385-4-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 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09.02.20 11:48, Baoquan He wrote: > Currently, subsection map is used when SPARSEMEM is enabled, including > VMEMMAP case and !VMEMMAP case. However, subsection hotplug is not > supported at all in SPARSEMEM|!VMEMMAP case, subsection map is unnecessary > and misleading. Let's adjust code to only allow subsection map being > used in SPARSEMEM|VMEMMAP case. > > Signed-off-by: Baoquan He > --- > include/linux/mmzone.h | 2 + > mm/sparse.c | 231 ++++++++++++++++++++++------------------- > 2 files changed, 124 insertions(+), 109 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index 462f6873905a..fc0de3a9a51e 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -1185,7 +1185,9 @@ 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 696f6b9f706e..cf55d272d0a9 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -209,41 +209,6 @@ static inline unsigned long first_present_section_nr(void) > return next_present_section_nr(-1); > } > > -static void subsection_mask_set(unsigned long *map, unsigned long pfn, > - unsigned long nr_pages) > -{ > - int idx = subsection_map_index(pfn); > - int end = subsection_map_index(pfn + nr_pages - 1); > - > - bitmap_set(map, idx, end - idx + 1); > -} > - > -void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) > -{ > - int end_sec = pfn_to_section_nr(pfn + nr_pages - 1); > - unsigned long nr, start_sec = pfn_to_section_nr(pfn); > - > - if (!nr_pages) > - return; > - > - for (nr = start_sec; nr <= end_sec; nr++) { > - struct mem_section *ms; > - unsigned long pfns; > - > - pfns = min(nr_pages, PAGES_PER_SECTION > - - (pfn & ~PAGE_SECTION_MASK)); > - ms = __nr_to_section(nr); > - subsection_mask_set(ms->usage->subsection_map, pfn, pfns); > - > - pr_debug("%s: sec: %lu pfns: %lu set(%d, %d)\n", __func__, nr, > - pfns, subsection_map_index(pfn), > - subsection_map_index(pfn + pfns - 1)); > - > - pfn += pfns; > - nr_pages -= pfns; > - } > -} > - > /* Record a memory area against a node. */ > void __init memory_present(int nid, unsigned long start, unsigned long end) > { > @@ -432,12 +397,134 @@ static unsigned long __init section_map_size(void) > return ALIGN(sizeof(struct page) * PAGES_PER_SECTION, PMD_SIZE); > } > > +static void subsection_mask_set(unsigned long *map, unsigned long pfn, > + unsigned long nr_pages) > +{ > + int idx = subsection_map_index(pfn); > + int end = subsection_map_index(pfn + nr_pages - 1); > + > + bitmap_set(map, idx, end - idx + 1); > +} > + > +void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) > +{ > + int end_sec = pfn_to_section_nr(pfn + nr_pages - 1); > + unsigned long nr, start_sec = pfn_to_section_nr(pfn); > + > + if (!nr_pages) > + return; > + > + for (nr = start_sec; nr <= end_sec; nr++) { > + struct mem_section *ms; > + unsigned long pfns; > + > + pfns = min(nr_pages, PAGES_PER_SECTION > + - (pfn & ~PAGE_SECTION_MASK)); > + ms = __nr_to_section(nr); > + subsection_mask_set(ms->usage->subsection_map, pfn, pfns); > + > + pr_debug("%s: sec: %lu pfns: %lu set(%d, %d)\n", __func__, nr, > + pfns, subsection_map_index(pfn), > + subsection_map_index(pfn + pfns - 1)); > + > + pfn += pfns; > + nr_pages -= pfns; > + } > +} > + > +/** > + * clear_subsection_map - Clear subsection map of one memory region > + * > + * @pfn - start pfn of the memory range > + * @nr_pages - number of pfns to add in the region > + * > + * This is only intended for hotplug, and clear the related subsection > + * map inside one section. > + * > + * Return: > + * * -EINVAL - Section already deactived. > + * * 0 - Subsection map is emptied. > + * * 1 - Subsection map is not empty. > + */ > +static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) > +{ > + DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; > + DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 }; > + struct mem_section *ms = __pfn_to_section(pfn); > + unsigned long *subsection_map = ms->usage > + ? &ms->usage->subsection_map[0] : NULL; > + > + subsection_mask_set(map, pfn, nr_pages); > + if (subsection_map) > + bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION); > + > + if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION), > + "section already deactivated (%#lx + %ld)\n", > + pfn, nr_pages)) > + return -EINVAL; > + > + bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); > + > + if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) > + return 0; > + > + return 1; > +} > + > +/** > + * fill_subsection_map - fill subsection map of a memory region > + * @pfn - start pfn of the memory range > + * @nr_pages - number of pfns to add in the region > + * > + * This clears the related subsection map inside one section, and only > + * intended for hotplug. > + * > + * Return: > + * * 0 - On success. > + * * -EINVAL - Invalid memory region. > + * * -EEXIST - Subsection map has been set. > + */ > +static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) > +{ > + struct mem_section *ms = __pfn_to_section(pfn); > + DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; > + unsigned long *subsection_map; > + int rc = 0; > + > + subsection_mask_set(map, pfn, nr_pages); > + > + subsection_map = &ms->usage->subsection_map[0]; > + > + if (bitmap_empty(map, SUBSECTIONS_PER_SECTION)) > + rc = -EINVAL; > + else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION)) > + rc = -EEXIST; > + else > + bitmap_or(subsection_map, map, subsection_map, > + SUBSECTIONS_PER_SECTION); > + > + return rc; > +} > + > #else > static unsigned long __init section_map_size(void) > { > return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION); > } > > +void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) > +{ > +} > + > +static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) > +{ > + return 0; > +} > +static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) > +{ > + return 0; > +} > + > struct page __init *__populate_section_memmap(unsigned long pfn, > unsigned long nr_pages, int nid, struct vmem_altmap *altmap) > { > @@ -726,45 +813,6 @@ static void free_map_bootmem(struct page *memmap) > } > #endif /* CONFIG_SPARSEMEM_VMEMMAP */ > > -/** > - * clear_subsection_map - Clear subsection map of one memory region > - * > - * @pfn - start pfn of the memory range > - * @nr_pages - number of pfns to add in the region > - * > - * This is only intended for hotplug, and clear the related subsection > - * map inside one section. > - * > - * Return: > - * * -EINVAL - Section already deactived. > - * * 0 - Subsection map is emptied. > - * * 1 - Subsection map is not empty. > - */ > -static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) > -{ > - DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; > - DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 }; > - struct mem_section *ms = __pfn_to_section(pfn); > - unsigned long *subsection_map = ms->usage > - ? &ms->usage->subsection_map[0] : NULL; > - > - subsection_mask_set(map, pfn, nr_pages); > - if (subsection_map) > - bitmap_and(tmp, map, subsection_map, SUBSECTIONS_PER_SECTION); > - > - if (WARN(!subsection_map || !bitmap_equal(tmp, map, SUBSECTIONS_PER_SECTION), > - "section already deactivated (%#lx + %ld)\n", > - pfn, nr_pages)) > - return -EINVAL; > - > - bitmap_xor(subsection_map, map, subsection_map, SUBSECTIONS_PER_SECTION); > - > - if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) > - return 0; > - > - return 1; > -} > - > static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > struct vmem_altmap *altmap) > { > @@ -818,41 +866,6 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > depopulate_section_memmap(pfn, nr_pages, altmap); > } > > -/** > - * fill_subsection_map - fill subsection map of a memory region > - * @pfn - start pfn of the memory range > - * @nr_pages - number of pfns to add in the region > - * > - * This clears the related subsection map inside one section, and only > - * intended for hotplug. > - * > - * Return: > - * * 0 - On success. > - * * -EINVAL - Invalid memory region. > - * * -EEXIST - Subsection map has been set. > - */ > -static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) > -{ > - struct mem_section *ms = __pfn_to_section(pfn); > - DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 }; > - unsigned long *subsection_map; > - int rc = 0; > - > - subsection_mask_set(map, pfn, nr_pages); > - > - subsection_map = &ms->usage->subsection_map[0]; > - > - if (bitmap_empty(map, SUBSECTIONS_PER_SECTION)) > - rc = -EINVAL; > - else if (bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION)) > - rc = -EEXIST; > - else > - bitmap_or(subsection_map, map, subsection_map, > - SUBSECTIONS_PER_SECTION); > - > - return rc; > -} > - > static struct page * __meminit section_activate(int nid, unsigned long pfn, > unsigned long nr_pages, struct vmem_altmap *altmap) > { > I'd prefer adding more ifdefs to avoid heavy code movement. Would make it much easier to review :) -- Thanks, David / dhildenb