#include <linux/memory.h>
#include <linux/random.h>
#include <linux/sched/sysctl.h>
+#include <linux/memory-tiers.h>
#include <asm/tlbflush.h>
#endif
folio_get(folio);
- pte = pte_mkold(mk_pte(new, READ_ONCE(vma->vm_page_prot)));
+ pte = mk_pte(new, READ_ONCE(vma->vm_page_prot));
if (pte_swp_soft_dirty(*pvmw.pte))
pte = pte_mksoft_dirty(pte);
* Recheck VMA as permissions can change since migration started
*/
entry = pte_to_swp_entry(*pvmw.pte);
+ if (!is_migration_entry_young(entry))
+ pte = pte_mkold(pte);
+ if (folio_test_dirty(folio) && is_migration_entry_dirty(entry))
+ pte = pte_mkdirty(pte);
if (is_writable_migration_entry(entry))
pte = maybe_mkwrite(pte, vma);
else if (pte_swp_uffd_wp(*pvmw.pte))
* future migrations of this same page.
*/
cpupid = page_cpupid_xchg_last(&folio->page, -1);
+ /*
+ * For memory tiering mode, when migrate between slow and fast
+ * memory node, reset cpupid, because that is used to record
+ * page access time in slow memory node.
+ */
+ if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) {
+ bool f_toptier = node_is_toptier(page_to_nid(&folio->page));
+ bool t_toptier = node_is_toptier(page_to_nid(&newfolio->page));
+
+ if (f_toptier != t_toptier)
+ cpupid = -1;
+ }
page_cpupid_xchg_last(&newfolio->page, cpupid);
folio_migrate_ksm(newfolio, folio);
* Migration functions
***********************************************************/
+int migrate_folio_extra(struct address_space *mapping, struct folio *dst,
+ struct folio *src, enum migrate_mode mode, int extra_count)
+{
+ int rc;
+
+ BUG_ON(folio_test_writeback(src)); /* Writeback must be complete */
+
+ rc = folio_migrate_mapping(mapping, dst, src, extra_count);
+
+ if (rc != MIGRATEPAGE_SUCCESS)
+ return rc;
+
+ if (mode != MIGRATE_SYNC_NO_COPY)
+ folio_migrate_copy(dst, src);
+ else
+ folio_migrate_flags(dst, src);
+ return MIGRATEPAGE_SUCCESS;
+}
+
/**
* migrate_folio() - Simple folio migration.
* @mapping: The address_space containing the folio.
int migrate_folio(struct address_space *mapping, struct folio *dst,
struct folio *src, enum migrate_mode mode)
{
- int rc;
-
- BUG_ON(folio_test_writeback(src)); /* Writeback must be complete */
-
- rc = folio_migrate_mapping(mapping, dst, src, 0);
-
- if (rc != MIGRATEPAGE_SUCCESS)
- return rc;
-
- if (mode != MIGRATE_SYNC_NO_COPY)
- folio_migrate_copy(dst, src);
- else
- folio_migrate_flags(dst, src);
- return MIGRATEPAGE_SUCCESS;
+ return migrate_folio_extra(mapping, dst, src, mode, 0);
}
EXPORT_SYMBOL(migrate_folio);
return rc;
}
-static int __unmap_and_move(struct page *page, struct page *newpage,
+static int __unmap_and_move(struct folio *src, struct folio *dst,
int force, enum migrate_mode mode)
{
- struct folio *folio = page_folio(page);
- struct folio *dst = page_folio(newpage);
int rc = -EAGAIN;
bool page_was_mapped = false;
struct anon_vma *anon_vma = NULL;
- bool is_lru = !__PageMovable(page);
+ bool is_lru = !__PageMovable(&src->page);
- if (!trylock_page(page)) {
+ if (!folio_trylock(src)) {
if (!force || mode == MIGRATE_ASYNC)
goto out;
if (current->flags & PF_MEMALLOC)
goto out;
- lock_page(page);
+ folio_lock(src);
}
- if (PageWriteback(page)) {
+ if (folio_test_writeback(src)) {
/*
* Only in the case of a full synchronous migration is it
* necessary to wait for PageWriteback. In the async case,
}
if (!force)
goto out_unlock;
- wait_on_page_writeback(page);
+ folio_wait_writeback(src);
}
/*
- * By try_to_migrate(), page->mapcount goes down to 0 here. In this case,
- * we cannot notice that anon_vma is freed while we migrates a page.
+ * By try_to_migrate(), src->mapcount goes down to 0 here. In this case,
+ * we cannot notice that anon_vma is freed while we migrate a page.
* This get_anon_vma() delays freeing anon_vma pointer until the end
* of migration. File cache pages are no problem because of page_lock()
* File Caches may use write_page() or lock_page() in migration, then,
* just care Anon page here.
*
- * Only page_get_anon_vma() understands the subtleties of
+ * Only folio_get_anon_vma() understands the subtleties of
* getting a hold on an anon_vma from outside one of its mms.
* But if we cannot get anon_vma, then we won't need it anyway,
* because that implies that the anon page is no longer mapped
* (and cannot be remapped so long as we hold the page lock).
*/
- if (PageAnon(page) && !PageKsm(page))
- anon_vma = page_get_anon_vma(page);
+ if (folio_test_anon(src) && !folio_test_ksm(src))
+ anon_vma = folio_get_anon_vma(src);
/*
* Block others from accessing the new page when we get around to
* establishing additional references. We are usually the only one
- * holding a reference to newpage at this point. We used to have a BUG
- * here if trylock_page(newpage) fails, but would like to allow for
- * cases where there might be a race with the previous use of newpage.
+ * holding a reference to dst at this point. We used to have a BUG
+ * here if folio_trylock(dst) fails, but would like to allow for
+ * cases where there might be a race with the previous use of dst.
* This is much like races on refcount of oldpage: just don't BUG().
*/
- if (unlikely(!trylock_page(newpage)))
+ if (unlikely(!folio_trylock(dst)))
goto out_unlock;
if (unlikely(!is_lru)) {
- rc = move_to_new_folio(dst, folio, mode);
+ rc = move_to_new_folio(dst, src, mode);
goto out_unlock_both;
}
* Corner case handling:
* 1. When a new swap-cache page is read into, it is added to the LRU
* and treated as swapcache but it has no rmap yet.
- * Calling try_to_unmap() against a page->mapping==NULL page will
+ * Calling try_to_unmap() against a src->mapping==NULL page will
* trigger a BUG. So handle it here.
* 2. An orphaned page (see truncate_cleanup_page) might have
* fs-private metadata. The page can be picked up due to memory
* invisible to the vm, so the page can not be migrated. So try to
* free the metadata, so the page can be freed.
*/
- if (!page->mapping) {
- VM_BUG_ON_PAGE(PageAnon(page), page);
- if (page_has_private(page)) {
- try_to_free_buffers(folio);
+ if (!src->mapping) {
+ if (folio_test_private(src)) {
+ try_to_free_buffers(src);
goto out_unlock_both;
}
- } else if (page_mapped(page)) {
+ } else if (folio_mapped(src)) {
/* Establish migration ptes */
- VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma,
- page);
- try_to_migrate(folio, 0);
+ VM_BUG_ON_FOLIO(folio_test_anon(src) &&
+ !folio_test_ksm(src) && !anon_vma, src);
+ try_to_migrate(src, 0);
page_was_mapped = true;
}
- if (!page_mapped(page))
- rc = move_to_new_folio(dst, folio, mode);
+ if (!folio_mapped(src))
+ rc = move_to_new_folio(dst, src, mode);
/*
- * When successful, push newpage to LRU immediately: so that if it
+ * When successful, push dst to LRU immediately: so that if it
* turns out to be an mlocked page, remove_migration_ptes() will
- * automatically build up the correct newpage->mlock_count for it.
+ * automatically build up the correct dst->mlock_count for it.
*
* We would like to do something similar for the old page, when
* unsuccessful, and other cases when a page has been temporarily
* isolated from the unevictable LRU: but this case is the easiest.
*/
if (rc == MIGRATEPAGE_SUCCESS) {
- lru_cache_add(newpage);
+ folio_add_lru(dst);
if (page_was_mapped)
lru_add_drain();
}
if (page_was_mapped)
- remove_migration_ptes(folio,
- rc == MIGRATEPAGE_SUCCESS ? dst : folio, false);
+ remove_migration_ptes(src,
+ rc == MIGRATEPAGE_SUCCESS ? dst : src, false);
out_unlock_both:
- unlock_page(newpage);
+ folio_unlock(dst);
out_unlock:
/* Drop an anon_vma reference if we took one */
if (anon_vma)
put_anon_vma(anon_vma);
- unlock_page(page);
+ folio_unlock(src);
out:
/*
- * If migration is successful, decrease refcount of the newpage,
+ * If migration is successful, decrease refcount of dst,
* which will not free the page because new page owner increased
* refcounter.
*/
if (rc == MIGRATEPAGE_SUCCESS)
- put_page(newpage);
+ folio_put(dst);
return rc;
}
enum migrate_reason reason,
struct list_head *ret)
{
+ struct folio *dst, *src = page_folio(page);
int rc = MIGRATEPAGE_SUCCESS;
struct page *newpage = NULL;
newpage = get_new_page(page, private);
if (!newpage)
return -ENOMEM;
+ dst = page_folio(newpage);
newpage->private = 0;
- rc = __unmap_and_move(page, newpage, force, mode);
+ rc = __unmap_and_move(src, dst, force, mode);
if (rc == MIGRATEPAGE_SUCCESS)
set_page_owner_migrate_reason(newpage, reason);
* tables or check whether the hugepage is pmd-based or not before
* kicking migration.
*/
- if (!hugepage_migration_supported(page_hstate(hpage))) {
- list_move_tail(&hpage->lru, ret);
+ if (!hugepage_migration_supported(page_hstate(hpage)))
return -ENOSYS;
- }
- if (page_count(hpage) == 1) {
+ if (folio_ref_count(src) == 1) {
/* page was freed from under us. So we are done. */
putback_active_hugepage(hpage);
return MIGRATEPAGE_SUCCESS;
return -ENOMEM;
dst = page_folio(new_hpage);
- if (!trylock_page(hpage)) {
+ if (!folio_trylock(src)) {
if (!force)
goto out;
switch (mode) {
default:
goto out;
}
- lock_page(hpage);
+ folio_lock(src);
}
/*
* Check for pages which are in the process of being freed. Without
- * page_mapping() set, hugetlbfs specific move page routine will not
+ * folio_mapping() set, hugetlbfs specific move page routine will not
* be called and we could leak usage counts for subpools.
*/
- if (hugetlb_page_subpool(hpage) && !page_mapping(hpage)) {
+ if (hugetlb_page_subpool(hpage) && !folio_mapping(src)) {
rc = -EBUSY;
goto out_unlock;
}
- if (PageAnon(hpage))
- anon_vma = page_get_anon_vma(hpage);
+ if (folio_test_anon(src))
+ anon_vma = folio_get_anon_vma(src);
- if (unlikely(!trylock_page(new_hpage)))
+ if (unlikely(!folio_trylock(dst)))
goto put_anon;
- if (page_mapped(hpage)) {
+ if (folio_mapped(src)) {
enum ttu_flags ttu = 0;
- if (!PageAnon(hpage)) {
+ if (!folio_test_anon(src)) {
/*
* In shared mappings, try_to_unmap could potentially
* call huge_pmd_unshare. Because of this, take
i_mmap_unlock_write(mapping);
}
- if (!page_mapped(hpage))
+ if (!folio_mapped(src))
rc = move_to_new_folio(dst, src, mode);
if (page_was_mapped)
rc == MIGRATEPAGE_SUCCESS ? dst : src, false);
unlock_put_anon:
- unlock_page(new_hpage);
+ folio_unlock(dst);
put_anon:
if (anon_vma)
}
out_unlock:
- unlock_page(hpage);
+ folio_unlock(src);
out:
if (rc == MIGRATEPAGE_SUCCESS)
putback_active_hugepage(hpage);
else if (rc != -EAGAIN)
- list_move_tail(&hpage->lru, ret);
+ list_move_tail(&src->lru, ret);
/*
* If migration was not successful and there's a freeing callback, use
return rc;
}
-static inline int try_split_thp(struct page *page, struct page **page2,
- struct list_head *from)
+static inline int try_split_thp(struct page *page, struct list_head *split_pages)
{
- int rc = 0;
+ int rc;
lock_page(page);
- rc = split_huge_page_to_list(page, from);
+ rc = split_huge_page_to_list(page, split_pages);
unlock_page(page);
if (!rc)
- list_safe_reset_next(page, *page2, lru);
+ list_move_tail(&page->lru, split_pages);
return rc;
}
int thp_retry = 1;
int nr_failed = 0;
int nr_failed_pages = 0;
+ int nr_retry_pages = 0;
int nr_succeeded = 0;
int nr_thp_succeeded = 0;
int nr_thp_failed = 0;
for (pass = 0; pass < 10 && (retry || thp_retry); pass++) {
retry = 0;
thp_retry = 0;
+ nr_retry_pages = 0;
list_for_each_entry_safe(page, page2, from, lru) {
-retry:
/*
* THP statistics is based on the source huge page.
* Capture required information that might get lost
* page will be put back
* -EAGAIN: stay on the from list
* -ENOMEM: stay on the from list
+ * -ENOSYS: stay on the from list
* Other errno: put on ret_pages list then splice to
* from list
*/
* retry on the same page with the THP split
* to base pages.
*
- * Head page is retried immediately and tail
- * pages are added to the tail of the list so
- * we encounter them after the rest of the list
- * is processed.
+ * Sub-pages are put in thp_split_pages, and
+ * we will migrate them after the rest of the
+ * list is processed.
*/
case -ENOSYS:
/* THP migration is unsupported */
if (is_thp) {
nr_thp_failed++;
- if (!try_split_thp(page, &page2, &thp_split_pages)) {
+ if (!try_split_thp(page, &thp_split_pages)) {
nr_thp_split++;
- goto retry;
+ break;
}
/* Hugetlb migration is unsupported */
} else if (!no_subpage_counting) {
}
nr_failed_pages += nr_subpages;
+ list_move_tail(&page->lru, &ret_pages);
break;
case -ENOMEM:
/*
* When memory is low, don't bother to try to migrate
* other pages, just exit.
- * THP NUMA faulting doesn't split THP to retry.
*/
- if (is_thp && !nosplit) {
+ if (is_thp) {
nr_thp_failed++;
- if (!try_split_thp(page, &page2, &thp_split_pages)) {
+ /* THP NUMA faulting doesn't split THP to retry. */
+ if (!nosplit && !try_split_thp(page, &thp_split_pages)) {
nr_thp_split++;
- goto retry;
+ break;
}
} else if (!no_subpage_counting) {
nr_failed++;
}
- nr_failed_pages += nr_subpages;
+ nr_failed_pages += nr_subpages + nr_retry_pages;
/*
* There might be some subpages of fail-to-migrate THPs
* left in thp_split_pages list. Move them back to migration
* the caller otherwise the page refcnt will be leaked.
*/
list_splice_init(&thp_split_pages, from);
+ /* nr_failed isn't updated for not used */
nr_thp_failed += thp_retry;
goto out;
case -EAGAIN:
if (is_thp)
thp_retry++;
- else
+ else if (!no_subpage_counting)
retry++;
+ nr_retry_pages += nr_subpages;
break;
case MIGRATEPAGE_SUCCESS:
nr_succeeded += nr_subpages;
}
nr_failed += retry;
nr_thp_failed += thp_retry;
+ nr_failed_pages += nr_retry_pages;
/*
* Try to migrate subpages of fail-to-migrate THPs, no nr_failed
* counting in this round, since all subpages of a THP is counted
goto out;
err = -ENOENT;
- if (!page || is_zone_device_page(page))
+ if (!page)
goto out;
+ if (is_zone_device_page(page))
+ goto out_putpage;
+
err = 0;
if (page_to_nid(page) == node)
goto out_putpage;
* well.
*/
if (err > 0)
- err += nr_pages - i - 1;
+ err += nr_pages - i;
return err;
}
return store_status(status, start, node, i - start);
err = move_pages_and_store_status(mm, current_node, &pagelist,
status, start, i, nr_pages);
- if (err)
+ if (err) {
+ /* We have accounted for page i */
+ if (err > 0)
+ err--;
goto out;
+ }
current_node = NUMA_NO_NODE;
}
out_flush:
for (i = 0; i < nr_pages; i++) {
unsigned long addr = (unsigned long)(*pages);
+ unsigned int foll_flags = FOLL_DUMP;
struct vm_area_struct *vma;
struct page *page;
int err = -EFAULT;
if (!vma)
goto set_status;
+ /* Not all huge page follow APIs support 'FOLL_GET' */
+ if (!is_vm_hugetlb_page(vma))
+ foll_flags |= FOLL_GET;
+
/* FOLL_DUMP to ignore special (like zero) pages */
- page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP);
+ page = follow_page(vma, addr, foll_flags);
err = PTR_ERR(page);
if (IS_ERR(page))
goto set_status;
- if (page && !is_zone_device_page(page)) {
+ err = -ENOENT;
+ if (!page)
+ goto set_status;
+
+ if (!is_zone_device_page(page))
err = page_to_nid(page);
+
+ if (foll_flags & FOLL_GET)
put_page(page);
- } else {
- err = -ENOENT;
- }
set_status:
*status = err;
return 0;
}
#endif /* CONFIG_NUMA_BALANCING */
-
-/*
- * node_demotion[] example:
- *
- * Consider a system with two sockets. Each socket has
- * three classes of memory attached: fast, medium and slow.
- * Each memory class is placed in its own NUMA node. The
- * CPUs are placed in the node with the "fast" memory. The
- * 6 NUMA nodes (0-5) might be split among the sockets like
- * this:
- *
- * Socket A: 0, 1, 2
- * Socket B: 3, 4, 5
- *
- * When Node 0 fills up, its memory should be migrated to
- * Node 1. When Node 1 fills up, it should be migrated to
- * Node 2. The migration path start on the nodes with the
- * processors (since allocations default to this node) and
- * fast memory, progress through medium and end with the
- * slow memory:
- *
- * 0 -> 1 -> 2 -> stop
- * 3 -> 4 -> 5 -> stop
- *
- * This is represented in the node_demotion[] like this:
- *
- * { nr=1, nodes[0]=1 }, // Node 0 migrates to 1
- * { nr=1, nodes[0]=2 }, // Node 1 migrates to 2
- * { nr=0, nodes[0]=-1 }, // Node 2 does not migrate
- * { nr=1, nodes[0]=4 }, // Node 3 migrates to 4
- * { nr=1, nodes[0]=5 }, // Node 4 migrates to 5
- * { nr=0, nodes[0]=-1 }, // Node 5 does not migrate
- *
- * Moreover some systems may have multiple slow memory nodes.
- * Suppose a system has one socket with 3 memory nodes, node 0
- * is fast memory type, and node 1/2 both are slow memory
- * type, and the distance between fast memory node and slow
- * memory node is same. So the migration path should be:
- *
- * 0 -> 1/2 -> stop
- *
- * This is represented in the node_demotion[] like this:
- * { nr=2, {nodes[0]=1, nodes[1]=2} }, // Node 0 migrates to node 1 and node 2
- * { nr=0, nodes[0]=-1, }, // Node 1 dose not migrate
- * { nr=0, nodes[0]=-1, }, // Node 2 does not migrate
- */
-
-/*
- * Writes to this array occur without locking. Cycles are
- * not allowed: Node X demotes to Y which demotes to X...
- *
- * If multiple reads are performed, a single rcu_read_lock()
- * must be held over all reads to ensure that no cycles are
- * observed.
- */
-#define DEFAULT_DEMOTION_TARGET_NODES 15
-
-#if MAX_NUMNODES < DEFAULT_DEMOTION_TARGET_NODES
-#define DEMOTION_TARGET_NODES (MAX_NUMNODES - 1)
-#else
-#define DEMOTION_TARGET_NODES DEFAULT_DEMOTION_TARGET_NODES
-#endif
-
-struct demotion_nodes {
- unsigned short nr;
- short nodes[DEMOTION_TARGET_NODES];
-};
-
-static struct demotion_nodes *node_demotion __read_mostly;
-
-/**
- * next_demotion_node() - Get the next node in the demotion path
- * @node: The starting node to lookup the next node
- *
- * Return: node id for next memory node in the demotion path hierarchy
- * from @node; NUMA_NO_NODE if @node is terminal. This does not keep
- * @node online or guarantee that it *continues* to be the next demotion
- * target.
- */
-int next_demotion_node(int node)
-{
- struct demotion_nodes *nd;
- unsigned short target_nr, index;
- int target;
-
- if (!node_demotion)
- return NUMA_NO_NODE;
-
- nd = &node_demotion[node];
-
- /*
- * node_demotion[] is updated without excluding this
- * function from running. RCU doesn't provide any
- * compiler barriers, so the READ_ONCE() is required
- * to avoid compiler reordering or read merging.
- *
- * Make sure to use RCU over entire code blocks if
- * node_demotion[] reads need to be consistent.
- */
- rcu_read_lock();
- target_nr = READ_ONCE(nd->nr);
-
- switch (target_nr) {
- case 0:
- target = NUMA_NO_NODE;
- goto out;
- case 1:
- index = 0;
- break;
- default:
- /*
- * If there are multiple target nodes, just select one
- * target node randomly.
- *
- * In addition, we can also use round-robin to select
- * target node, but we should introduce another variable
- * for node_demotion[] to record last selected target node,
- * that may cause cache ping-pong due to the changing of
- * last target node. Or introducing per-cpu data to avoid
- * caching issue, which seems more complicated. So selecting
- * target node randomly seems better until now.
- */
- index = get_random_int() % target_nr;
- break;
- }
-
- target = READ_ONCE(nd->nodes[index]);
-
-out:
- rcu_read_unlock();
- return target;
-}
-
-/* Disable reclaim-based migration. */
-static void __disable_all_migrate_targets(void)
-{
- int node, i;
-
- if (!node_demotion)
- return;
-
- for_each_online_node(node) {
- node_demotion[node].nr = 0;
- for (i = 0; i < DEMOTION_TARGET_NODES; i++)
- node_demotion[node].nodes[i] = NUMA_NO_NODE;
- }
-}
-
-static void disable_all_migrate_targets(void)
-{
- __disable_all_migrate_targets();
-
- /*
- * Ensure that the "disable" is visible across the system.
- * Readers will see either a combination of before+disable
- * state or disable+after. They will never see before and
- * after state together.
- *
- * The before+after state together might have cycles and
- * could cause readers to do things like loop until this
- * function finishes. This ensures they can only see a
- * single "bad" read and would, for instance, only loop
- * once.
- */
- synchronize_rcu();
-}
-
-/*
- * Find an automatic demotion target for 'node'.
- * Failing here is OK. It might just indicate
- * being at the end of a chain.
- */
-static int establish_migrate_target(int node, nodemask_t *used,
- int best_distance)
-{
- int migration_target, index, val;
- struct demotion_nodes *nd;
-
- if (!node_demotion)
- return NUMA_NO_NODE;
-
- nd = &node_demotion[node];
-
- migration_target = find_next_best_node(node, used);
- if (migration_target == NUMA_NO_NODE)
- return NUMA_NO_NODE;
-
- /*
- * If the node has been set a migration target node before,
- * which means it's the best distance between them. Still
- * check if this node can be demoted to other target nodes
- * if they have a same best distance.
- */
- if (best_distance != -1) {
- val = node_distance(node, migration_target);
- if (val > best_distance)
- goto out_clear;
- }
-
- index = nd->nr;
- if (WARN_ONCE(index >= DEMOTION_TARGET_NODES,
- "Exceeds maximum demotion target nodes\n"))
- goto out_clear;
-
- nd->nodes[index] = migration_target;
- nd->nr++;
-
- return migration_target;
-out_clear:
- node_clear(migration_target, *used);
- return NUMA_NO_NODE;
-}
-
-/*
- * When memory fills up on a node, memory contents can be
- * automatically migrated to another node instead of
- * discarded at reclaim.
- *
- * Establish a "migration path" which will start at nodes
- * with CPUs and will follow the priorities used to build the
- * page allocator zonelists.
- *
- * The difference here is that cycles must be avoided. If
- * node0 migrates to node1, then neither node1, nor anything
- * node1 migrates to can migrate to node0. Also one node can
- * be migrated to multiple nodes if the target nodes all have
- * a same best-distance against the source node.
- *
- * This function can run simultaneously with readers of
- * node_demotion[]. However, it can not run simultaneously
- * with itself. Exclusion is provided by memory hotplug events
- * being single-threaded.
- */
-static void __set_migration_target_nodes(void)
-{
- nodemask_t next_pass;
- nodemask_t this_pass;
- nodemask_t used_targets = NODE_MASK_NONE;
- int node, best_distance;
-
- /*
- * Avoid any oddities like cycles that could occur
- * from changes in the topology. This will leave
- * a momentary gap when migration is disabled.
- */
- disable_all_migrate_targets();
-
- /*
- * Allocations go close to CPUs, first. Assume that
- * the migration path starts at the nodes with CPUs.
- */
- next_pass = node_states[N_CPU];
-again:
- this_pass = next_pass;
- next_pass = NODE_MASK_NONE;
- /*
- * To avoid cycles in the migration "graph", ensure
- * that migration sources are not future targets by
- * setting them in 'used_targets'. Do this only
- * once per pass so that multiple source nodes can
- * share a target node.
- *
- * 'used_targets' will become unavailable in future
- * passes. This limits some opportunities for
- * multiple source nodes to share a destination.
- */
- nodes_or(used_targets, used_targets, this_pass);
-
- for_each_node_mask(node, this_pass) {
- best_distance = -1;
-
- /*
- * Try to set up the migration path for the node, and the target
- * migration nodes can be multiple, so doing a loop to find all
- * the target nodes if they all have a best node distance.
- */
- do {
- int target_node =
- establish_migrate_target(node, &used_targets,
- best_distance);
-
- if (target_node == NUMA_NO_NODE)
- break;
-
- if (best_distance == -1)
- best_distance = node_distance(node, target_node);
-
- /*
- * Visit targets from this pass in the next pass.
- * Eventually, every node will have been part of
- * a pass, and will become set in 'used_targets'.
- */
- node_set(target_node, next_pass);
- } while (1);
- }
- /*
- * 'next_pass' contains nodes which became migration
- * targets in this pass. Make additional passes until
- * no more migrations targets are available.
- */
- if (!nodes_empty(next_pass))
- goto again;
-}
-
-/*
- * For callers that do not hold get_online_mems() already.
- */
-void set_migration_target_nodes(void)
-{
- get_online_mems();
- __set_migration_target_nodes();
- put_online_mems();
-}
-
-/*
- * This leaves migrate-on-reclaim transiently disabled between
- * the MEM_GOING_OFFLINE and MEM_OFFLINE events. This runs
- * whether reclaim-based migration is enabled or not, which
- * ensures that the user can turn reclaim-based migration at
- * any time without needing to recalculate migration targets.
- *
- * These callbacks already hold get_online_mems(). That is why
- * __set_migration_target_nodes() can be used as opposed to
- * set_migration_target_nodes().
- */
-#ifdef CONFIG_MEMORY_HOTPLUG
-static int __meminit migrate_on_reclaim_callback(struct notifier_block *self,
- unsigned long action, void *_arg)
-{
- struct memory_notify *arg = _arg;
-
- /*
- * Only update the node migration order when a node is
- * changing status, like online->offline. This avoids
- * the overhead of synchronize_rcu() in most cases.
- */
- if (arg->status_change_nid < 0)
- return notifier_from_errno(0);
-
- switch (action) {
- case MEM_GOING_OFFLINE:
- /*
- * Make sure there are not transient states where
- * an offline node is a migration target. This
- * will leave migration disabled until the offline
- * completes and the MEM_OFFLINE case below runs.
- */
- disable_all_migrate_targets();
- break;
- case MEM_OFFLINE:
- case MEM_ONLINE:
- /*
- * Recalculate the target nodes once the node
- * reaches its final state (online or offline).
- */
- __set_migration_target_nodes();
- break;
- case MEM_CANCEL_OFFLINE:
- /*
- * MEM_GOING_OFFLINE disabled all the migration
- * targets. Reenable them.
- */
- __set_migration_target_nodes();
- break;
- case MEM_GOING_ONLINE:
- case MEM_CANCEL_ONLINE:
- break;
- }
-
- return notifier_from_errno(0);
-}
-#endif
-
-void __init migrate_on_reclaim_init(void)
-{
- node_demotion = kcalloc(nr_node_ids,
- sizeof(struct demotion_nodes),
- GFP_KERNEL);
- WARN_ON(!node_demotion);
-#ifdef CONFIG_MEMORY_HOTPLUG
- hotplug_memory_notifier(migrate_on_reclaim_callback, 100);
-#endif
- /*
- * At this point, all numa nodes with memory/CPus have their state
- * properly set, so we can build the demotion order now.
- * Let us hold the cpu_hotplug lock just, as we could possibily have
- * CPU hotplug events during boot.
- */
- cpus_read_lock();
- set_migration_target_nodes();
- cpus_read_unlock();
-}
-
-bool numa_demotion_enabled = false;
-
-#ifdef CONFIG_SYSFS
-static ssize_t numa_demotion_enabled_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
-{
- return sysfs_emit(buf, "%s\n",
- numa_demotion_enabled ? "true" : "false");
-}
-
-static ssize_t numa_demotion_enabled_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- ssize_t ret;
-
- ret = kstrtobool(buf, &numa_demotion_enabled);
- if (ret)
- return ret;
-
- return count;
-}
-
-static struct kobj_attribute numa_demotion_enabled_attr =
- __ATTR(demotion_enabled, 0644, numa_demotion_enabled_show,
- numa_demotion_enabled_store);
-
-static struct attribute *numa_attrs[] = {
- &numa_demotion_enabled_attr.attr,
- NULL,
-};
-
-static const struct attribute_group numa_attr_group = {
- .attrs = numa_attrs,
-};
-
-static int __init numa_init_sysfs(void)
-{
- int err;
- struct kobject *numa_kobj;
-
- numa_kobj = kobject_create_and_add("numa", mm_kobj);
- if (!numa_kobj) {
- pr_err("failed to create numa kobject\n");
- return -ENOMEM;
- }
- err = sysfs_create_group(numa_kobj, &numa_attr_group);
- if (err) {
- pr_err("failed to register numa group\n");
- goto delete_obj;
- }
- return 0;
-
-delete_obj:
- kobject_put(numa_kobj);
- return err;
-}
-subsys_initcall(numa_init_sysfs);
-#endif /* CONFIG_SYSFS */
#endif /* CONFIG_NUMA */
projects / platform / kernel / linux-starfive.git / blobdiff