Messages in this thread Patch in this message | | | Date | Tue, 09 May 2006 15:28:03 +0100 | From | Andy Whitcroft <> | Subject | Re: [PATCH] SPARSEMEM + NUMA can't handle unaligned memory regions? |
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Andy Whitcroft wrote:
> We see to have a few options: > > 1) default the nid to something -- right now most of the non powerpc > architectures return 0 when the nid cannot be found thus avoiding this > panic. > > 2) nid search -- we can do pretty much what is in this patch probabally > with some optimisations like trying the first and last pfn in the > section first. > > 3) record the nid -- when we record the memory present in the system we > are passed the nid. > > Somehow the last of these seems the most logical given we have the > correct information at the time we record that we need to instantiate > the section. So I had a quick go at something which seems to have come > out pretty clean. Attached is a completly untested patch to show what I > am proposing.
Ok. Attached is a version which builds and boots. The patch looks pretty simple. Michael could you give it a spin on the broken machine for me.
-apw sparsemem record nid during memory present
Record the node id as we mark sections for instantiation. Use this nid during instantiation to direct allocations.
Signed-off-by: Andy Whitcroft <apw@shadowen.org> --- sparse.c | 22 ++++++++++++++++++++-- 1 files changed, 20 insertions(+), 2 deletions(-) diff -upN reference/mm/sparse.c current/mm/sparse.c --- reference/mm/sparse.c +++ current/mm/sparse.c @@ -102,6 +102,22 @@ int __section_nr(struct mem_section* ms) return (root_nr * SECTIONS_PER_ROOT) + (ms - root); } +/* + * During early boot we need to record the nid from which we will + * later allocate the section mem_map. Encode this into the section + * pointer. Overload the section_mem_map with this information. + */ +static inline unsigned long sparse_encode_early_nid(int nid) +{ + return (nid << SECTION_MAP_LAST_BIT); +} + +static inline int sparse_early_nid(struct mem_section *section) +{ + unsigned long nid = section->section_mem_map; + return (nid >> SECTION_MAP_LAST_BIT); +} + /* Record a memory area against a node. */ void memory_present(int nid, unsigned long start, unsigned long end) { @@ -116,7 +132,8 @@ void memory_present(int nid, unsigned lo ms = __nr_to_section(section); if (!ms->section_mem_map) - ms->section_mem_map = SECTION_MARKED_PRESENT; + ms->section_mem_map = sparse_encode_early_nid(nid) | + SECTION_MARKED_PRESENT; } } @@ -167,6 +184,7 @@ static int sparse_init_one_section(struc if (!valid_section(ms)) return -EINVAL; + ms->section_mem_map &= ~SECTION_MAP_MASK; ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum); return 1; @@ -175,8 +193,8 @@ static int sparse_init_one_section(struc static struct page *sparse_early_mem_map_alloc(unsigned long pnum) { struct page *map; - int nid = early_pfn_to_nid(section_nr_to_pfn(pnum)); struct mem_section *ms = __nr_to_section(pnum); + int nid = sparse_early_nid(ms); map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION); if (map) | |