mm/sparsemem.c: defer the ms->section_mem_map clearing

In sparse_init(), if CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER=y, system
will allocate one continuous memory chunk for mem maps on one node and
populate the relevant page tables to map memory section one by one.  If
fail to populate for a certain mem section, print warning and its
->section_mem_map will be cleared to cancel the marking of being
present.  Like this, the number of mem sections marked as present could
become less during sparse_init() execution.

Here just defer the ms->section_mem_map clearing if failed to populate
its page tables until the last for_each_present_section_nr() loop.  This
is in preparation for later optimizing the mem map allocation.

[[email protected]: remove now-unused local `ms', per Oscar]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Baoquan He <[email protected]>
Acked-by: Dave Hansen <[email protected]>
Reviewed-by: Pavel Tatashin <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Cc: Pasha Tatashin <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Pankaj Gupta <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index bd0276d5f66b17f6b6c78e503b91972c7677e599..68bb65b2d34d8929edb0743a4b8a83fb4d9b44c6 100644 (file)
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -292,18 +292,14 @@ void __init sparse_mem_maps_populate_node(struct page **map_map,
        }
 
        for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
        }
 
        for (pnum = pnum_begin; pnum < pnum_end; pnum++) {

-               struct mem_section *ms;
-

                if (!present_section_nr(pnum))
                        continue;
 
                map_map[pnum] = sparse_mem_map_populate(pnum, nodeid, NULL);
                if (map_map[pnum])
                        continue;
                if (!present_section_nr(pnum))
                        continue;
 
                map_map[pnum] = sparse_mem_map_populate(pnum, nodeid, NULL);
                if (map_map[pnum])
                        continue;

-               ms = __nr_to_section(pnum);

                pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
                       __func__);
                pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
                       __func__);

-               ms->section_mem_map = 0;

        }
 
        if (vmemmap_buf_start) {
        }
 
        if (vmemmap_buf_start) {

diff --git a/mm/sparse.c b/mm/sparse.c
index 99a6383e98bc73ecd345263308b7e25eb9849a2e..eb31274aae8b7709c34a937e3bac8dc10c194574 100644 (file)
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -446,7 +446,6 @@ void __init sparse_mem_maps_populate_node(struct page **map_map,
                ms = __nr_to_section(pnum);
                pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
                       __func__);
                ms = __nr_to_section(pnum);
                pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
                       __func__);

-               ms->section_mem_map = 0;

        }
 }
 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
        }
 }
 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */


@@ -474,7 +473,6 @@ static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum)
 
        pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
               __func__);
 
        pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
               __func__);

-       ms->section_mem_map = 0;

        return NULL;
 }
 #endif
        return NULL;
 }
 #endif


@@ -578,17 +576,23 @@ void __init sparse_init(void)
 #endif
 
        for_each_present_section_nr(0, pnum) {
 #endif
 
        for_each_present_section_nr(0, pnum) {

+               struct mem_section *ms;
+               ms = __nr_to_section(pnum);

                usemap = usemap_map[pnum];
                usemap = usemap_map[pnum];

-               if (!usemap)
+               if (!usemap) {
+                       ms->section_mem_map = 0;

                        continue;
                        continue;

+               }

 
 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
                map = map_map[pnum];
 #else
                map = sparse_early_mem_map_alloc(pnum);
 #endif
 
 #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
                map = map_map[pnum];
 #else
                map = sparse_early_mem_map_alloc(pnum);
 #endif

-               if (!map)
+               if (!map) {
+                       ms->section_mem_map = 0;

                        continue;
                        continue;

+               }

 
                sparse_init_one_section(__nr_to_section(pnum), pnum, map,
                                                                usemap);
 
                sparse_init_one_section(__nr_to_section(pnum), pnum, map,
                                                                usemap);