mm/sparsemem: prepare for sub-section ranges

Prepare the memory hot-{add,remove} paths for handling sub-section
ranges by plumbing the starting page frame and number of pages being
handled through arch_{add,remove}_memory() to
sparse_{add,remove}_one_section().

This is simply plumbing, small cleanups, and some identifier renames.
No intended functional changes.

Link: http://lkml.kernel.org/r/156092353780.979959.9713046515562743194.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>	[ppc64]
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 475aff8..2d636a7 100644 (file)
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -346,9 +346,10 @@ extern int add_memory_resource(int nid, struct resource *resource);
 extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
                unsigned long nr_pages, struct vmem_altmap *altmap);
 extern bool is_memblock_offlined(struct memory_block *mem);
-extern int sparse_add_one_section(int nid, unsigned long start_pfn,
-                                 struct vmem_altmap *altmap);
+extern int sparse_add_section(int nid, unsigned long pfn,
+               unsigned long nr_pages, struct vmem_altmap *altmap);
 extern void sparse_remove_one_section(struct mem_section *ms,
+               unsigned long pfn, unsigned long nr_pages,
                unsigned long map_offset, struct vmem_altmap *altmap);
 extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
                                          unsigned long pnum);

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1122004..3fbb2cf 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -252,51 +252,84 @@ void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
 }
 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
 
-static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
-                                  struct vmem_altmap *altmap)
+static int __meminit __add_section(int nid, unsigned long pfn,
+               unsigned long nr_pages, struct vmem_altmap *altmap)
 {
        int ret;
 
-       if (pfn_valid(phys_start_pfn))
+       if (pfn_valid(pfn))
                return -EEXIST;
 
-       ret = sparse_add_one_section(nid, phys_start_pfn, altmap);
+       ret = sparse_add_section(nid, pfn, nr_pages, altmap);
        return ret < 0 ? ret : 0;
 }
 
+static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
+               const char *reason)
+{
+       /*
+        * Disallow all operations smaller than a sub-section and only
+        * allow operations smaller than a section for
+        * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
+        * enforces a larger memory_block_size_bytes() granularity for
+        * memory that will be marked online, so this check should only
+        * fire for direct arch_{add,remove}_memory() users outside of
+        * add_memory_resource().
+        */
+       unsigned long min_align;
+
+       if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
+               min_align = PAGES_PER_SUBSECTION;
+       else
+               min_align = PAGES_PER_SECTION;
+       if (!IS_ALIGNED(pfn, min_align)
+                       || !IS_ALIGNED(nr_pages, min_align)) {
+               WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
+                               reason, pfn, pfn + nr_pages - 1);
+               return -EINVAL;
+       }
+       return 0;
+}
+
 /*
  * Reasonably generic function for adding memory.  It is
  * expected that archs that support memory hotplug will
  * call this function after deciding the zone to which to
  * add the new pages.
  */
-int __ref __add_pages(int nid, unsigned long phys_start_pfn,
-               unsigned long nr_pages, struct mhp_restrictions *restrictions)
+int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
+               struct mhp_restrictions *restrictions)
 {
        unsigned long i;
-       int err = 0;
-       int start_sec, end_sec;
+       int start_sec, end_sec, err;
        struct vmem_altmap *altmap = restrictions->altmap;
 
-       /* during initialize mem_map, align hot-added range to section */
-       start_sec = pfn_to_section_nr(phys_start_pfn);
-       end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
-
        if (altmap) {
                /*
                 * Validate altmap is within bounds of the total request
                 */
-               if (altmap->base_pfn != phys_start_pfn
+               if (altmap->base_pfn != pfn
                                || vmem_altmap_offset(altmap) > nr_pages) {
                        pr_warn_once("memory add fail, invalid altmap\n");
-                       err = -EINVAL;
-                       goto out;
+                       return -EINVAL;
                }
                altmap->alloc = 0;
        }
 
+       err = check_pfn_span(pfn, nr_pages, "add");
+       if (err)
+               return err;
+
+       start_sec = pfn_to_section_nr(pfn);
+       end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
        for (i = start_sec; i <= end_sec; i++) {
-               err = __add_section(nid, section_nr_to_pfn(i), altmap);
+               unsigned long pfns;
+
+               pfns = min(nr_pages, PAGES_PER_SECTION
+                               - (pfn & ~PAGE_SECTION_MASK));
+               err = __add_section(nid, pfn, pfns, altmap);
+               pfn += pfns;
+               nr_pages -= pfns;
 
                /*
                 * EEXIST is finally dealt with by ioresource collision
@@ -309,7 +342,6 @@ int __ref __add_pages(int nid, unsigned long phys_start_pfn,
                cond_resched();
        }
        vmemmap_populate_print_last();
-out:
        return err;
 }
 
@@ -487,10 +519,10 @@ static void shrink_pgdat_span(struct pglist_data *pgdat,
        pgdat->node_spanned_pages = 0;
 }
 
-static void __remove_zone(struct zone *zone, unsigned long start_pfn)
+static void __remove_zone(struct zone *zone, unsigned long start_pfn,
+               unsigned long nr_pages)
 {
        struct pglist_data *pgdat = zone->zone_pgdat;
-       int nr_pages = PAGES_PER_SECTION;
        unsigned long flags;
 
        pgdat_resize_lock(zone->zone_pgdat, &flags);
@@ -499,27 +531,23 @@ static void __remove_zone(struct zone *zone, unsigned long start_pfn)
        pgdat_resize_unlock(zone->zone_pgdat, &flags);
 }
 
-static void __remove_section(struct zone *zone, struct mem_section *ms,
-                            unsigned long map_offset,
-                            struct vmem_altmap *altmap)
+static void __remove_section(struct zone *zone, unsigned long pfn,
+               unsigned long nr_pages, unsigned long map_offset,
+               struct vmem_altmap *altmap)
 {
-       unsigned long start_pfn;
-       int scn_nr;
+       struct mem_section *ms = __nr_to_section(pfn_to_section_nr(pfn));
 
        if (WARN_ON_ONCE(!valid_section(ms)))
                return;
 
-       scn_nr = __section_nr(ms);
-       start_pfn = section_nr_to_pfn((unsigned long)scn_nr);
-       __remove_zone(zone, start_pfn);
-
-       sparse_remove_one_section(ms, map_offset, altmap);
+       __remove_zone(zone, pfn, nr_pages);
+       sparse_remove_one_section(ms, pfn, nr_pages, map_offset, altmap);
 }
 
 /**
  * __remove_pages() - remove sections of pages from a zone
  * @zone: zone from which pages need to be removed
- * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
+ * @pfn: starting pageframe (must be aligned to start of a section)
  * @nr_pages: number of pages to remove (must be multiple of section size)
  * @altmap: alternative device page map or %NULL if default memmap is used
  *
@@ -528,30 +556,30 @@ static void __remove_section(struct zone *zone, struct mem_section *ms,
  * sure that pages are marked reserved and zones are adjust properly by
  * calling offline_pages().
  */
-void __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
+void __remove_pages(struct zone *zone, unsigned long pfn,
                    unsigned long nr_pages, struct vmem_altmap *altmap)
 {
-       unsigned long i;
        unsigned long map_offset = 0;
-       int sections_to_remove;
+       int i, start_sec, end_sec;
 
        map_offset = vmem_altmap_offset(altmap);
 
        clear_zone_contiguous(zone);
 
-       /*
-        * We can only remove entire sections
-        */
-       BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
-       BUG_ON(nr_pages % PAGES_PER_SECTION);
+       if (check_pfn_span(pfn, nr_pages, "remove"))
+               return;
 
-       sections_to_remove = nr_pages / PAGES_PER_SECTION;
-       for (i = 0; i < sections_to_remove; i++) {
-               unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
+       start_sec = pfn_to_section_nr(pfn);
+       end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
+       for (i = start_sec; i <= end_sec; i++) {
+               unsigned long pfns;
 
                cond_resched();
-               __remove_section(zone, __pfn_to_section(pfn), map_offset,
-                                altmap);
+               pfns = min(nr_pages, PAGES_PER_SECTION
+                               - (pfn & ~PAGE_SECTION_MASK));
+               __remove_section(zone, pfn, pfns, map_offset, altmap);
+               pfn += pfns;
+               nr_pages -= pfns;
                map_offset = 0;
        }
 

diff --git a/mm/sparse.c b/mm/sparse.c
index 6b01022..41579b6 100644 (file)
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -728,8 +728,8 @@ static void free_map_bootmem(struct page *memmap)
  * * -EEXIST   - Section has been present.
  * * -ENOMEM   - Out of memory.
  */
-int __meminit sparse_add_one_section(int nid, unsigned long start_pfn,
-                                    struct vmem_altmap *altmap)
+int __meminit sparse_add_section(int nid, unsigned long start_pfn,
+               unsigned long nr_pages, struct vmem_altmap *altmap)
 {
        unsigned long section_nr = pfn_to_section_nr(start_pfn);
        struct mem_section_usage *usage;
@@ -835,8 +835,9 @@ static void free_section_usage(struct mem_section *ms, struct page *memmap,
                free_map_bootmem(memmap);
 }
 
-void sparse_remove_one_section(struct mem_section *ms, unsigned long map_offset,
-                              struct vmem_altmap *altmap)
+void sparse_remove_one_section(struct mem_section *ms, unsigned long pfn,
+               unsigned long nr_pages, unsigned long map_offset,
+               struct vmem_altmap *altmap)
 {
        struct page *memmap = NULL;
        struct mem_section_usage *usage = NULL;
@@ -849,10 +850,7 @@ void sparse_remove_one_section(struct mem_section *ms, unsigned long map_offset,
                ms->usage = NULL;
        }
 
-       clear_hwpoisoned_pages(memmap + map_offset,
-                       PAGES_PER_SECTION - map_offset);
-       free_section_usage(ms, memmap, usage,
-                       section_nr_to_pfn(__section_nr(ms)),
-                       PAGES_PER_SECTION, altmap);
+       clear_hwpoisoned_pages(memmap + map_offset, nr_pages - map_offset);
+       free_section_usage(ms, memmap, usage, pfn, nr_pages, altmap);
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */