| Message ID | 20190616023554.19316-1-richardw.yang@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/sparse: set section nid for hot-add memory | expand |
On 06/16/2019 08:05 AM, Wei Yang wrote: > section_to_node_table[] is used to record section's node id, which is > used in page_to_nid(). While for hot-add memory, this is missed. Used for NODE_NOT_IN_PAGE_FLAGS case and it is missed for hot-added memory. > > BTW, current online_pages works because it leverages nid in memory_block. It does. > But the granularity of node id should be mem_section wide. Right. > > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
On Mon, Jun 17, 2019 at 09:53:05AM +0530, Anshuman Khandual wrote: >On 06/16/2019 08:05 AM, Wei Yang wrote: >> section_to_node_table[] is used to record section's node id, which is >> used in page_to_nid(). While for hot-add memory, this is missed. > >Used for NODE_NOT_IN_PAGE_FLAGS case and it is missed for hot-added memory. > >> >> BTW, current online_pages works because it leverages nid in memory_block. > >It does. > >> But the granularity of node id should be mem_section wide. > >Right. > >> >> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> > >Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Thanks
On 16.06.19 04:35, Wei Yang wrote: > section_to_node_table[] is used to record section's node id, which is > used in page_to_nid(). While for hot-add memory, this is missed. > > BTW, current online_pages works because it leverages nid in memory_block. > But the granularity of node id should be mem_section wide. set_section_nid() is only relevant if the NID is not part of the vmemmaps. > > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> > --- > mm/sparse.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/sparse.c b/mm/sparse.c > index fd13166949b5..3ba8f843cb7a 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -735,6 +735,7 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn, > */ > page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION); > > + set_section_nid(section_nr, nid); > section_mark_present(ms); > sparse_init_one_section(ms, section_nr, memmap, usemap); > > Although I dislike basically all of the current ->nid design, this seems to be the right thing to do Reviewed-by: David Hildenbrand <david@redhat.com>
On Sun, Jun 16, 2019 at 10:35:54AM +0800, Wei Yang wrote: > section_to_node_table[] is used to record section's node id, which is > used in page_to_nid(). While for hot-add memory, this is missed. > > BTW, current online_pages works because it leverages nid in memory_block. > But the granularity of node id should be mem_section wide. > > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> While the patch is valid, I think that the changelog could be improved a bit. For example, I would point out the possible problems we can face if it is not set properly (e.g: page_to_nid() operations failing to give the right node) and when section_to_node_table[] is used (NODE_NOT_IN_PAGE_FLAGS scenario). Reviewed-by: Oscar Salvador <osalvador@suse.de> > --- > mm/sparse.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/sparse.c b/mm/sparse.c > index fd13166949b5..3ba8f843cb7a 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -735,6 +735,7 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn, > */ > page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION); > > + set_section_nid(section_nr, nid); > section_mark_present(ms); > sparse_init_one_section(ms, section_nr, memmap, usemap); > > -- > 2.19.1 >
On Mon, Jun 17, 2019 at 03:13:33PM +0200, David Hildenbrand wrote: >On 16.06.19 04:35, Wei Yang wrote: >> section_to_node_table[] is used to record section's node id, which is >> used in page_to_nid(). While for hot-add memory, this is missed. >> >> BTW, current online_pages works because it leverages nid in memory_block. >> But the granularity of node id should be mem_section wide. > >set_section_nid() is only relevant if the NID is not part of the vmemmaps. > Yep, you are right. >> >> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> >> --- >> mm/sparse.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/mm/sparse.c b/mm/sparse.c >> index fd13166949b5..3ba8f843cb7a 100644 >> --- a/mm/sparse.c >> +++ b/mm/sparse.c >> @@ -735,6 +735,7 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn, >> */ >> page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION); >> >> + set_section_nid(section_nr, nid); >> section_mark_present(ms); >> sparse_init_one_section(ms, section_nr, memmap, usemap); >> >> > >Although I dislike basically all of the current ->nid design, this seems >to be the right thing to do > >Reviewed-by: David Hildenbrand <david@redhat.com> > >-- > >Thanks, > >David / dhildenb
On Mon, Jun 17, 2019 at 05:43:25PM +0200, Oscar Salvador wrote: >On Sun, Jun 16, 2019 at 10:35:54AM +0800, Wei Yang wrote: >> section_to_node_table[] is used to record section's node id, which is >> used in page_to_nid(). While for hot-add memory, this is missed. >> >> BTW, current online_pages works because it leverages nid in memory_block. >> But the granularity of node id should be mem_section wide. >> >> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> > >While the patch is valid, I think that the changelog could be improved a bit. >For example, I would point out the possible problems we can face if it is not set >properly (e.g: page_to_nid() operations failing to give the right node) and when >section_to_node_table[] is used (NODE_NOT_IN_PAGE_FLAGS scenario). > Thanks, let me give more words on this. >Reviewed-by: Oscar Salvador <osalvador@suse.de> > >> --- >> mm/sparse.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/mm/sparse.c b/mm/sparse.c >> index fd13166949b5..3ba8f843cb7a 100644 >> --- a/mm/sparse.c >> +++ b/mm/sparse.c >> @@ -735,6 +735,7 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn, >> */ >> page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION); >> >> + set_section_nid(section_nr, nid); >> section_mark_present(ms); >> sparse_init_one_section(ms, section_nr, memmap, usemap); >> >> -- >> 2.19.1 >> > >-- >Oscar Salvador >SUSE L3
diff --git a/mm/sparse.c b/mm/sparse.c index fd13166949b5..3ba8f843cb7a 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -735,6 +735,7 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn, */ page_init_poison(memmap, sizeof(struct page) * PAGES_PER_SECTION); + set_section_nid(section_nr, nid); section_mark_present(ms); sparse_init_one_section(ms, section_nr, memmap, usemap);
section_to_node_table[] is used to record section's node id, which is used in page_to_nid(). While for hot-add memory, this is missed. BTW, current online_pages works because it leverages nid in memory_block. But the granularity of node id should be mem_section wide. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> --- mm/sparse.c | 1 + 1 file changed, 1 insertion(+)