| Message ID | 155977187919.2443951.8925592545929008845.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: Sub-section memory hotplug support | expand |
On Wed, Jun 05, 2019 at 02:57:59PM -0700, Dan Williams wrote: > Prepare for hot{plug,remove} of sub-ranges of a section by tracking a > sub-section active bitmask, each bit representing a PMD_SIZE span of the > architecture's memory hotplug section size. > > The implications of a partially populated section is that pfn_valid() > needs to go beyond a valid_section() check and read the sub-section > active ranges from the bitmask. The expectation is that the bitmask > (subsection_map) fits in the same cacheline as the valid_section() data, > so the incremental performance overhead to pfn_valid() should be > negligible. > > Cc: Michal Hocko <mhocko@suse.com> > Cc: Vlastimil Babka <vbabka@suse.cz> > Cc: Logan Gunthorpe <logang@deltatee.com> > Cc: Oscar Salvador <osalvador@suse.de> > Cc: Pavel Tatashin <pasha.tatashin@soleen.com> > Tested-by: Jane Chu <jane.chu@oracle.com> > Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de>
On Wed, Jun 05, 2019 at 02:57:59PM -0700, Dan Williams wrote: >Prepare for hot{plug,remove} of sub-ranges of a section by tracking a >sub-section active bitmask, each bit representing a PMD_SIZE span of the >architecture's memory hotplug section size. > >The implications of a partially populated section is that pfn_valid() >needs to go beyond a valid_section() check and read the sub-section >active ranges from the bitmask. The expectation is that the bitmask >(subsection_map) fits in the same cacheline as the valid_section() data, >so the incremental performance overhead to pfn_valid() should be >negligible. > >Cc: Michal Hocko <mhocko@suse.com> >Cc: Vlastimil Babka <vbabka@suse.cz> >Cc: Logan Gunthorpe <logang@deltatee.com> >Cc: Oscar Salvador <osalvador@suse.de> >Cc: Pavel Tatashin <pasha.tatashin@soleen.com> >Tested-by: Jane Chu <jane.chu@oracle.com> >Signed-off-by: Dan Williams <dan.j.williams@intel.com> >--- > include/linux/mmzone.h | 29 ++++++++++++++++++++++++++++- > mm/page_alloc.c | 4 +++- > mm/sparse.c | 35 +++++++++++++++++++++++++++++++++++ > 3 files changed, 66 insertions(+), 2 deletions(-) > >diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h >index ac163f2f274f..6dd52d544857 100644 >--- a/include/linux/mmzone.h >+++ b/include/linux/mmzone.h >@@ -1199,6 +1199,8 @@ struct mem_section_usage { > unsigned long pageblock_flags[0]; > }; > >+void subsection_map_init(unsigned long pfn, unsigned long nr_pages); >+ > struct page; > struct page_ext; > struct mem_section { >@@ -1336,12 +1338,36 @@ static inline struct mem_section *__pfn_to_section(unsigned long pfn) > > extern int __highest_present_section_nr; > >+static inline int subsection_map_index(unsigned long pfn) >+{ >+ return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION; >+} >+ >+#ifdef CONFIG_SPARSEMEM_VMEMMAP >+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) >+{ >+ int idx = subsection_map_index(pfn); >+ >+ return test_bit(idx, ms->usage->subsection_map); >+} >+#else >+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) >+{ >+ return 1; >+} >+#endif >+ > #ifndef CONFIG_HAVE_ARCH_PFN_VALID > static inline int pfn_valid(unsigned long pfn) > { >+ struct mem_section *ms; >+ > if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > return 0; >- return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); >+ ms = __nr_to_section(pfn_to_section_nr(pfn)); >+ if (!valid_section(ms)) >+ return 0; >+ return pfn_section_valid(ms, pfn); > } > #endif > >@@ -1373,6 +1399,7 @@ void sparse_init(void); > #define sparse_init() do {} while (0) > #define sparse_index_init(_sec, _nid) do {} while (0) > #define pfn_present pfn_valid >+#define subsection_map_init(_pfn, _nr_pages) do {} while (0) > #endif /* CONFIG_SPARSEMEM */ > > /* >diff --git a/mm/page_alloc.c b/mm/page_alloc.c >index c6d8224d792e..bd773efe5b82 100644 >--- a/mm/page_alloc.c >+++ b/mm/page_alloc.c >@@ -7292,10 +7292,12 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) > > /* Print out the early node map */ > pr_info("Early memory node ranges\n"); >- for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) >+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { > pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid, > (u64)start_pfn << PAGE_SHIFT, > ((u64)end_pfn << PAGE_SHIFT) - 1); >+ subsection_map_init(start_pfn, end_pfn - start_pfn); >+ } Just curious about why we set subsection here? Function free_area_init_nodes() mostly handles pgdat, if I am correct. Setup subsection here looks like touching some lower level system data structure. > > /* Initialise every node */ > mminit_verify_pageflags_layout(); >diff --git a/mm/sparse.c b/mm/sparse.c >index 71da15cc7432..0baa2e55cfdd 100644 >--- a/mm/sparse.c >+++ b/mm/sparse.c >@@ -210,6 +210,41 @@ static inline unsigned long first_present_section_nr(void) > return next_present_section_nr(-1); > } > >+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 subsection_map_init(unsigned long pfn, unsigned long nr_pages) >+{ >+ int end_sec = pfn_to_section_nr(pfn + nr_pages - 1); >+ int i, start_sec = pfn_to_section_nr(pfn); >+ >+ if (!nr_pages) >+ return; >+ >+ for (i = start_sec; i <= end_sec; i++) { >+ struct mem_section *ms; >+ unsigned long pfns; >+ >+ pfns = min(nr_pages, PAGES_PER_SECTION >+ - (pfn & ~PAGE_SECTION_MASK)); >+ ms = __nr_to_section(i); >+ subsection_mask_set(ms->usage->subsection_map, pfn, pfns); >+ >+ pr_debug("%s: sec: %d pfns: %ld set(%d, %d)\n", __func__, i, >+ 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) > {
On Mon, Jun 17, 2019 at 3:22 PM Wei Yang <richard.weiyang@gmail.com> wrote: > > On Wed, Jun 05, 2019 at 02:57:59PM -0700, Dan Williams wrote: > >Prepare for hot{plug,remove} of sub-ranges of a section by tracking a > >sub-section active bitmask, each bit representing a PMD_SIZE span of the > >architecture's memory hotplug section size. > > > >The implications of a partially populated section is that pfn_valid() > >needs to go beyond a valid_section() check and read the sub-section > >active ranges from the bitmask. The expectation is that the bitmask > >(subsection_map) fits in the same cacheline as the valid_section() data, > >so the incremental performance overhead to pfn_valid() should be > >negligible. > > > >Cc: Michal Hocko <mhocko@suse.com> > >Cc: Vlastimil Babka <vbabka@suse.cz> > >Cc: Logan Gunthorpe <logang@deltatee.com> > >Cc: Oscar Salvador <osalvador@suse.de> > >Cc: Pavel Tatashin <pasha.tatashin@soleen.com> > >Tested-by: Jane Chu <jane.chu@oracle.com> > >Signed-off-by: Dan Williams <dan.j.williams@intel.com> > >--- > > include/linux/mmzone.h | 29 ++++++++++++++++++++++++++++- > > mm/page_alloc.c | 4 +++- > > mm/sparse.c | 35 +++++++++++++++++++++++++++++++++++ > > 3 files changed, 66 insertions(+), 2 deletions(-) > > > >diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > >index ac163f2f274f..6dd52d544857 100644 > >--- a/include/linux/mmzone.h > >+++ b/include/linux/mmzone.h > >@@ -1199,6 +1199,8 @@ struct mem_section_usage { > > unsigned long pageblock_flags[0]; > > }; > > > >+void subsection_map_init(unsigned long pfn, unsigned long nr_pages); > >+ > > struct page; > > struct page_ext; > > struct mem_section { > >@@ -1336,12 +1338,36 @@ static inline struct mem_section *__pfn_to_section(unsigned long pfn) > > > > extern int __highest_present_section_nr; > > > >+static inline int subsection_map_index(unsigned long pfn) > >+{ > >+ return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION; > >+} > >+ > >+#ifdef CONFIG_SPARSEMEM_VMEMMAP > >+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) > >+{ > >+ int idx = subsection_map_index(pfn); > >+ > >+ return test_bit(idx, ms->usage->subsection_map); > >+} > >+#else > >+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) > >+{ > >+ return 1; > >+} > >+#endif > >+ > > #ifndef CONFIG_HAVE_ARCH_PFN_VALID > > static inline int pfn_valid(unsigned long pfn) > > { > >+ struct mem_section *ms; > >+ > > if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > > return 0; > >- return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); > >+ ms = __nr_to_section(pfn_to_section_nr(pfn)); > >+ if (!valid_section(ms)) > >+ return 0; > >+ return pfn_section_valid(ms, pfn); > > } > > #endif > > > >@@ -1373,6 +1399,7 @@ void sparse_init(void); > > #define sparse_init() do {} while (0) > > #define sparse_index_init(_sec, _nid) do {} while (0) > > #define pfn_present pfn_valid > >+#define subsection_map_init(_pfn, _nr_pages) do {} while (0) > > #endif /* CONFIG_SPARSEMEM */ > > > > /* > >diff --git a/mm/page_alloc.c b/mm/page_alloc.c > >index c6d8224d792e..bd773efe5b82 100644 > >--- a/mm/page_alloc.c > >+++ b/mm/page_alloc.c > >@@ -7292,10 +7292,12 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) > > > > /* Print out the early node map */ > > pr_info("Early memory node ranges\n"); > >- for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) > >+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { > > pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid, > > (u64)start_pfn << PAGE_SHIFT, > > ((u64)end_pfn << PAGE_SHIFT) - 1); > >+ subsection_map_init(start_pfn, end_pfn - start_pfn); > >+ } > > Just curious about why we set subsection here? > > Function free_area_init_nodes() mostly handles pgdat, if I am correct. Setup > subsection here looks like touching some lower level system data structure. Correct, I'm not sure how it ended up there, but it was the source of a bug that was fixed with this change: https://lore.kernel.org/lkml/CAPcyv4hjvBPDYKpp2Gns3-cc2AQ0AVS1nLk-K3fwXeRUvvzQLg@mail.gmail.com/
On Mon, Jun 17, 2019 at 03:32:45PM -0700, Dan Williams wrote: >On Mon, Jun 17, 2019 at 3:22 PM Wei Yang <richard.weiyang@gmail.com> wrote: >> >> On Wed, Jun 05, 2019 at 02:57:59PM -0700, Dan Williams wrote: >> >Prepare for hot{plug,remove} of sub-ranges of a section by tracking a >> >sub-section active bitmask, each bit representing a PMD_SIZE span of the >> >architecture's memory hotplug section size. >> > >> >The implications of a partially populated section is that pfn_valid() >> >needs to go beyond a valid_section() check and read the sub-section >> >active ranges from the bitmask. The expectation is that the bitmask >> >(subsection_map) fits in the same cacheline as the valid_section() data, >> >so the incremental performance overhead to pfn_valid() should be >> >negligible. >> > >> >Cc: Michal Hocko <mhocko@suse.com> >> >Cc: Vlastimil Babka <vbabka@suse.cz> >> >Cc: Logan Gunthorpe <logang@deltatee.com> >> >Cc: Oscar Salvador <osalvador@suse.de> >> >Cc: Pavel Tatashin <pasha.tatashin@soleen.com> >> >Tested-by: Jane Chu <jane.chu@oracle.com> >> >Signed-off-by: Dan Williams <dan.j.williams@intel.com> >> >--- >> > include/linux/mmzone.h | 29 ++++++++++++++++++++++++++++- >> > mm/page_alloc.c | 4 +++- >> > mm/sparse.c | 35 +++++++++++++++++++++++++++++++++++ >> > 3 files changed, 66 insertions(+), 2 deletions(-) >> > >> >diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h >> >index ac163f2f274f..6dd52d544857 100644 >> >--- a/include/linux/mmzone.h >> >+++ b/include/linux/mmzone.h >> >@@ -1199,6 +1199,8 @@ struct mem_section_usage { >> > unsigned long pageblock_flags[0]; >> > }; >> > >> >+void subsection_map_init(unsigned long pfn, unsigned long nr_pages); >> >+ >> > struct page; >> > struct page_ext; >> > struct mem_section { >> >@@ -1336,12 +1338,36 @@ static inline struct mem_section *__pfn_to_section(unsigned long pfn) >> > >> > extern int __highest_present_section_nr; >> > >> >+static inline int subsection_map_index(unsigned long pfn) >> >+{ >> >+ return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION; >> >+} >> >+ >> >+#ifdef CONFIG_SPARSEMEM_VMEMMAP >> >+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) >> >+{ >> >+ int idx = subsection_map_index(pfn); >> >+ >> >+ return test_bit(idx, ms->usage->subsection_map); >> >+} >> >+#else >> >+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) >> >+{ >> >+ return 1; >> >+} >> >+#endif >> >+ >> > #ifndef CONFIG_HAVE_ARCH_PFN_VALID >> > static inline int pfn_valid(unsigned long pfn) >> > { >> >+ struct mem_section *ms; >> >+ >> > if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) >> > return 0; >> >- return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); >> >+ ms = __nr_to_section(pfn_to_section_nr(pfn)); >> >+ if (!valid_section(ms)) >> >+ return 0; >> >+ return pfn_section_valid(ms, pfn); >> > } >> > #endif >> > >> >@@ -1373,6 +1399,7 @@ void sparse_init(void); >> > #define sparse_init() do {} while (0) >> > #define sparse_index_init(_sec, _nid) do {} while (0) >> > #define pfn_present pfn_valid >> >+#define subsection_map_init(_pfn, _nr_pages) do {} while (0) >> > #endif /* CONFIG_SPARSEMEM */ >> > >> > /* >> >diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> >index c6d8224d792e..bd773efe5b82 100644 >> >--- a/mm/page_alloc.c >> >+++ b/mm/page_alloc.c >> >@@ -7292,10 +7292,12 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) >> > >> > /* Print out the early node map */ >> > pr_info("Early memory node ranges\n"); >> >- for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) >> >+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { >> > pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid, >> > (u64)start_pfn << PAGE_SHIFT, >> > ((u64)end_pfn << PAGE_SHIFT) - 1); >> >+ subsection_map_init(start_pfn, end_pfn - start_pfn); >> >+ } >> >> Just curious about why we set subsection here? >> >> Function free_area_init_nodes() mostly handles pgdat, if I am correct. Setup >> subsection here looks like touching some lower level system data structure. > >Correct, I'm not sure how it ended up there, but it was the source of >a bug that was fixed with this change: > >https://lore.kernel.org/lkml/CAPcyv4hjvBPDYKpp2Gns3-cc2AQ0AVS1nLk-K3fwXeRUvvzQLg@mail.gmail.com/ So this one is moved to sparse_init_nid(). The bug is strange, while the code now is more reasonable to me. Thanks :-) >_______________________________________________ >Linux-nvdimm mailing list >Linux-nvdimm@lists.01.org >https://lists.01.org/mailman/listinfo/linux-nvdimm
On Mon, Jun 17, 2019 at 3:32 PM Dan Williams <dan.j.williams@intel.com> wrote: > > On Mon, Jun 17, 2019 at 3:22 PM Wei Yang <richard.weiyang@gmail.com> wrote: > > > > On Wed, Jun 05, 2019 at 02:57:59PM -0700, Dan Williams wrote: > > >Prepare for hot{plug,remove} of sub-ranges of a section by tracking a > > >sub-section active bitmask, each bit representing a PMD_SIZE span of the > > >architecture's memory hotplug section size. > > > > > >The implications of a partially populated section is that pfn_valid() > > >needs to go beyond a valid_section() check and read the sub-section > > >active ranges from the bitmask. The expectation is that the bitmask > > >(subsection_map) fits in the same cacheline as the valid_section() data, > > >so the incremental performance overhead to pfn_valid() should be > > >negligible. > > > > > >Cc: Michal Hocko <mhocko@suse.com> > > >Cc: Vlastimil Babka <vbabka@suse.cz> > > >Cc: Logan Gunthorpe <logang@deltatee.com> > > >Cc: Oscar Salvador <osalvador@suse.de> > > >Cc: Pavel Tatashin <pasha.tatashin@soleen.com> > > >Tested-by: Jane Chu <jane.chu@oracle.com> > > >Signed-off-by: Dan Williams <dan.j.williams@intel.com> > > >--- > > > include/linux/mmzone.h | 29 ++++++++++++++++++++++++++++- > > > mm/page_alloc.c | 4 +++- > > > mm/sparse.c | 35 +++++++++++++++++++++++++++++++++++ > > > 3 files changed, 66 insertions(+), 2 deletions(-) > > > > > >diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > > >index ac163f2f274f..6dd52d544857 100644 > > >--- a/include/linux/mmzone.h > > >+++ b/include/linux/mmzone.h > > >@@ -1199,6 +1199,8 @@ struct mem_section_usage { > > > unsigned long pageblock_flags[0]; > > > }; > > > > > >+void subsection_map_init(unsigned long pfn, unsigned long nr_pages); > > >+ > > > struct page; > > > struct page_ext; > > > struct mem_section { > > >@@ -1336,12 +1338,36 @@ static inline struct mem_section *__pfn_to_section(unsigned long pfn) > > > > > > extern int __highest_present_section_nr; > > > > > >+static inline int subsection_map_index(unsigned long pfn) > > >+{ > > >+ return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION; > > >+} > > >+ > > >+#ifdef CONFIG_SPARSEMEM_VMEMMAP > > >+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) > > >+{ > > >+ int idx = subsection_map_index(pfn); > > >+ > > >+ return test_bit(idx, ms->usage->subsection_map); > > >+} > > >+#else > > >+static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) > > >+{ > > >+ return 1; > > >+} > > >+#endif > > >+ > > > #ifndef CONFIG_HAVE_ARCH_PFN_VALID > > > static inline int pfn_valid(unsigned long pfn) > > > { > > >+ struct mem_section *ms; > > >+ > > > if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > > > return 0; > > >- return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); > > >+ ms = __nr_to_section(pfn_to_section_nr(pfn)); > > >+ if (!valid_section(ms)) > > >+ return 0; > > >+ return pfn_section_valid(ms, pfn); > > > } > > > #endif > > > > > >@@ -1373,6 +1399,7 @@ void sparse_init(void); > > > #define sparse_init() do {} while (0) > > > #define sparse_index_init(_sec, _nid) do {} while (0) > > > #define pfn_present pfn_valid > > >+#define subsection_map_init(_pfn, _nr_pages) do {} while (0) > > > #endif /* CONFIG_SPARSEMEM */ > > > > > > /* > > >diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > >index c6d8224d792e..bd773efe5b82 100644 > > >--- a/mm/page_alloc.c > > >+++ b/mm/page_alloc.c > > >@@ -7292,10 +7292,12 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) > > > > > > /* Print out the early node map */ > > > pr_info("Early memory node ranges\n"); > > >- for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) > > >+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { > > > pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid, > > > (u64)start_pfn << PAGE_SHIFT, > > > ((u64)end_pfn << PAGE_SHIFT) - 1); > > >+ subsection_map_init(start_pfn, end_pfn - start_pfn); > > >+ } > > > > Just curious about why we set subsection here? > > > > Function free_area_init_nodes() mostly handles pgdat, if I am correct. Setup > > subsection here looks like touching some lower level system data structure. > > Correct, I'm not sure how it ended up there, but it was the source of > a bug that was fixed with this change: > > https://lore.kernel.org/lkml/CAPcyv4hjvBPDYKpp2Gns3-cc2AQ0AVS1nLk-K3fwXeRUvvzQLg@mail.gmail.com/ On second thought I'm going to keep subsection_map_init() in free_area_init_nodes(), but instead teach pfn_valid() to return true for all "early" sections. There are code paths that use pfn_valid() as a coarse check before validating against pgdat for real validity of online memory. It is sufficient and safe for those to assume that all early sections are fully pfn_valid, while ZONE_DEVICE hotplug can see the more precise subsection_map.
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index ac163f2f274f..6dd52d544857 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1199,6 +1199,8 @@ struct mem_section_usage { unsigned long pageblock_flags[0]; }; +void subsection_map_init(unsigned long pfn, unsigned long nr_pages); + struct page; struct page_ext; struct mem_section { @@ -1336,12 +1338,36 @@ static inline struct mem_section *__pfn_to_section(unsigned long pfn) extern int __highest_present_section_nr; +static inline int subsection_map_index(unsigned long pfn) +{ + return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION; +} + +#ifdef CONFIG_SPARSEMEM_VMEMMAP +static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) +{ + int idx = subsection_map_index(pfn); + + return test_bit(idx, ms->usage->subsection_map); +} +#else +static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) +{ + return 1; +} +#endif + #ifndef CONFIG_HAVE_ARCH_PFN_VALID static inline int pfn_valid(unsigned long pfn) { + struct mem_section *ms; + if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) return 0; - return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); + ms = __nr_to_section(pfn_to_section_nr(pfn)); + if (!valid_section(ms)) + return 0; + return pfn_section_valid(ms, pfn); } #endif @@ -1373,6 +1399,7 @@ void sparse_init(void); #define sparse_init() do {} while (0) #define sparse_index_init(_sec, _nid) do {} while (0) #define pfn_present pfn_valid +#define subsection_map_init(_pfn, _nr_pages) do {} while (0) #endif /* CONFIG_SPARSEMEM */ /* diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c6d8224d792e..bd773efe5b82 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7292,10 +7292,12 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn) /* Print out the early node map */ pr_info("Early memory node ranges\n"); - for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) + for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid, (u64)start_pfn << PAGE_SHIFT, ((u64)end_pfn << PAGE_SHIFT) - 1); + subsection_map_init(start_pfn, end_pfn - start_pfn); + } /* Initialise every node */ mminit_verify_pageflags_layout(); diff --git a/mm/sparse.c b/mm/sparse.c index 71da15cc7432..0baa2e55cfdd 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -210,6 +210,41 @@ static inline unsigned long first_present_section_nr(void) return next_present_section_nr(-1); } +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 subsection_map_init(unsigned long pfn, unsigned long nr_pages) +{ + int end_sec = pfn_to_section_nr(pfn + nr_pages - 1); + int i, start_sec = pfn_to_section_nr(pfn); + + if (!nr_pages) + return; + + for (i = start_sec; i <= end_sec; i++) { + struct mem_section *ms; + unsigned long pfns; + + pfns = min(nr_pages, PAGES_PER_SECTION + - (pfn & ~PAGE_SECTION_MASK)); + ms = __nr_to_section(i); + subsection_mask_set(ms->usage->subsection_map, pfn, pfns); + + pr_debug("%s: sec: %d pfns: %ld set(%d, %d)\n", __func__, i, + 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) {
Prepare for hot{plug,remove} of sub-ranges of a section by tracking a sub-section active bitmask, each bit representing a PMD_SIZE span of the architecture's memory hotplug section size. The implications of a partially populated section is that pfn_valid() needs to go beyond a valid_section() check and read the sub-section active ranges from the bitmask. The expectation is that the bitmask (subsection_map) fits in the same cacheline as the valid_section() data, so the incremental performance overhead to pfn_valid() should be negligible. Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Tested-by: Jane Chu <jane.chu@oracle.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- include/linux/mmzone.h | 29 ++++++++++++++++++++++++++++- mm/page_alloc.c | 4 +++- mm/sparse.c | 35 +++++++++++++++++++++++++++++++++++ 3 files changed, 66 insertions(+), 2 deletions(-)