[mm PATCH v7 3/4] mm: Implement new zone specific memblock iterator

From: Alexander Duyck
Date: Fri Apr 05 2019 - 18:12:31 EST


From: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>

Introduce a new iterator for_each_free_mem_pfn_range_in_zone.

This iterator will take care of making sure a given memory range provided
is in fact contained within a zone. It takes are of all the bounds checking
we were doing in deferred_grow_zone, and deferred_init_memmap. In addition
it should help to speed up the search a bit by iterating until the end of a
range is greater than the start of the zone pfn range, and will exit
completely if the start is beyond the end of the zone.

Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
---
include/linux/memblock.h | 25 ++++++++++++++++++
mm/memblock.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++
mm/page_alloc.c | 31 +++++++++-------------
3 files changed, 101 insertions(+), 19 deletions(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 294d5d80e150..f8b78892b977 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -240,6 +240,31 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
i >= 0; __next_mem_pfn_range(&i, nid, p_start, p_end, p_nid))
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */

+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+void __next_mem_pfn_range_in_zone(u64 *idx, struct zone *zone,
+ unsigned long *out_spfn,
+ unsigned long *out_epfn);
+/**
+ * for_each_free_mem_range_in_zone - iterate through zone specific free
+ * memblock areas
+ * @i: u64 used as loop variable
+ * @zone: zone in which all of the memory blocks reside
+ * @p_start: ptr to phys_addr_t for start address of the range, can be %NULL
+ * @p_end: ptr to phys_addr_t for end address of the range, can be %NULL
+ *
+ * Walks over free (memory && !reserved) areas of memblock in a specific
+ * zone. Available once memblock and an empty zone is initialized. The main
+ * assumption is that the zone start, end, and pgdat have been associated.
+ * This way we can use the zone to determine NUMA node, and if a given part
+ * of the memblock is valid for the zone.
+ */
+#define for_each_free_mem_pfn_range_in_zone(i, zone, p_start, p_end) \
+ for (i = 0, \
+ __next_mem_pfn_range_in_zone(&i, zone, p_start, p_end); \
+ i != U64_MAX; \
+ __next_mem_pfn_range_in_zone(&i, zone, p_start, p_end))
+#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
+
/**
* for_each_free_mem_range - iterate through free memblock areas
* @i: u64 used as loop variable
diff --git a/mm/memblock.c b/mm/memblock.c
index e7665cf914b1..28fa8926d9f8 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1255,6 +1255,70 @@ int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size,
return 0;
}
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+/**
+ * __next_mem_pfn_range_in_zone - iterator for for_each_*_range_in_zone()
+ *
+ * @idx: pointer to u64 loop variable
+ * @zone: zone in which all of the memory blocks reside
+ * @out_spfn: ptr to ulong for start pfn of the range, can be %NULL
+ * @out_epfn: ptr to ulong for end pfn of the range, can be %NULL
+ *
+ * This function is meant to be a zone/pfn specific wrapper for the
+ * for_each_mem_range type iterators. Specifically they are used in the
+ * deferred memory init routines and as such we were duplicating much of
+ * this logic throughout the code. So instead of having it in multiple
+ * locations it seemed like it would make more sense to centralize this to
+ * one new iterator that does everything they need.
+ */
+void __init_memblock
+__next_mem_pfn_range_in_zone(u64 *idx, struct zone *zone,
+ unsigned long *out_spfn, unsigned long *out_epfn)
+{
+ int zone_nid = zone_to_nid(zone);
+ phys_addr_t spa, epa;
+ int nid;
+
+ __next_mem_range(idx, zone_nid, MEMBLOCK_NONE,
+ &memblock.memory, &memblock.reserved,
+ &spa, &epa, &nid);
+
+ while (*idx != U64_MAX) {
+ unsigned long epfn = PFN_DOWN(epa);
+ unsigned long spfn = PFN_UP(spa);
+
+ /*
+ * Verify the end is at least past the start of the zone and
+ * that we have at least one PFN to initialize.
+ */
+ if (zone->zone_start_pfn < epfn && spfn < epfn) {
+ /* if we went too far just stop searching */
+ if (zone_end_pfn(zone) <= spfn) {
+ *idx = U64_MAX;
+ break;
+ }
+
+ if (out_spfn)
+ *out_spfn = max(zone->zone_start_pfn, spfn);
+ if (out_epfn)
+ *out_epfn = min(zone_end_pfn(zone), epfn);
+
+ return;
+ }
+
+ __next_mem_range(idx, zone_nid, MEMBLOCK_NONE,
+ &memblock.memory, &memblock.reserved,
+ &spa, &epa, &nid);
+ }
+
+ /* signal end of iteration */
+ if (out_spfn)
+ *out_spfn = ULONG_MAX;
+ if (out_epfn)
+ *out_epfn = 0;
+}
+
+#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */

/**
* memblock_alloc_range_nid - allocate boot memory block
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2d2bca9803d2..61467e28c966 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1613,11 +1613,9 @@ static unsigned long __init deferred_init_pages(struct zone *zone,
static int __init deferred_init_memmap(void *data)
{
pg_data_t *pgdat = data;
- int nid = pgdat->node_id;
unsigned long start = jiffies;
unsigned long nr_pages = 0;
unsigned long spfn, epfn, first_init_pfn, flags;
- phys_addr_t spa, epa;
int zid;
struct zone *zone;
const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
@@ -1654,14 +1652,12 @@ static int __init deferred_init_memmap(void *data)
* freeing pages we can access pages that are ahead (computing buddy
* page in __free_one_page()).
*/
- for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &spa, &epa, NULL) {
- spfn = max_t(unsigned long, first_init_pfn, PFN_UP(spa));
- epfn = min_t(unsigned long, zone_end_pfn(zone), PFN_DOWN(epa));
+ for_each_free_mem_pfn_range_in_zone(i, zone, &spfn, &epfn) {
+ spfn = max_t(unsigned long, first_init_pfn, spfn);
nr_pages += deferred_init_pages(zone, spfn, epfn);
}
- for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &spa, &epa, NULL) {
- spfn = max_t(unsigned long, first_init_pfn, PFN_UP(spa));
- epfn = min_t(unsigned long, zone_end_pfn(zone), PFN_DOWN(epa));
+ for_each_free_mem_pfn_range_in_zone(i, zone, &spfn, &epfn) {
+ spfn = max_t(unsigned long, first_init_pfn, spfn);
deferred_free_pages(spfn, epfn);
}
pgdat_resize_unlock(pgdat, &flags);
@@ -1669,8 +1665,8 @@ static int __init deferred_init_memmap(void *data)
/* Sanity check that the next zone really is unpopulated */
WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));

- pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages,
- jiffies_to_msecs(jiffies - start));
+ pr_info("node %d initialised, %lu pages in %ums\n",
+ pgdat->node_id, nr_pages, jiffies_to_msecs(jiffies - start));

pgdat_init_report_one_done();
return 0;
@@ -1694,13 +1690,11 @@ static int __init deferred_init_memmap(void *data)
static noinline bool __init
deferred_grow_zone(struct zone *zone, unsigned int order)
{
- int nid = zone_to_nid(zone);
- pg_data_t *pgdat = NODE_DATA(nid);
unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
+ pg_data_t *pgdat = zone->zone_pgdat;
unsigned long nr_pages = 0;
unsigned long first_init_pfn, spfn, epfn, t, flags;
unsigned long first_deferred_pfn = pgdat->first_deferred_pfn;
- phys_addr_t spa, epa;
u64 i;

/* Only the last zone may have deferred pages */
@@ -1736,9 +1730,8 @@ static int __init deferred_init_memmap(void *data)
return false;
}

- for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &spa, &epa, NULL) {
- spfn = max_t(unsigned long, first_init_pfn, PFN_UP(spa));
- epfn = min_t(unsigned long, zone_end_pfn(zone), PFN_DOWN(epa));
+ for_each_free_mem_pfn_range_in_zone(i, zone, &spfn, &epfn) {
+ spfn = max_t(unsigned long, first_init_pfn, spfn);

while (spfn < epfn && nr_pages < nr_pages_needed) {
t = ALIGN(spfn + PAGES_PER_SECTION, PAGES_PER_SECTION);
@@ -1752,9 +1745,9 @@ static int __init deferred_init_memmap(void *data)
break;
}

- for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &spa, &epa, NULL) {
- spfn = max_t(unsigned long, first_init_pfn, PFN_UP(spa));
- epfn = min_t(unsigned long, first_deferred_pfn, PFN_DOWN(epa));
+ for_each_free_mem_pfn_range_in_zone(i, zone, &spfn, &epfn) {
+ spfn = max_t(unsigned long, first_init_pfn, spfn);
+ epfn = min_t(unsigned long, first_deferred_pfn, epfn);
deferred_free_pages(spfn, epfn);

if (first_deferred_pfn == epfn)