Provide a mechanism to opt private nodes into userland numa management. Add node_allows_user_numa() to encapsulate whether a node supports userland NUMA controls (always true for normal nodes).
Placement - setting mempolicy via: - mbind() - set_mempolicy() - set_mempolicy_home_node() For mempolicy, enforcement lives in one place: mpol_set_nodemask() Private nodes are not N_MEMORY, so they are trimmed from a nodemask like a cpuset-trimmed node. All-private nodemasks without a valid node collapse to empty and the mempolicy fails. home_node is not special-cased - it is only a preferred-nid hint, and placement is governed by the bind nodemask, so a home node pointed at an invalid node simply falls back via the normal fallback zonelists. (All the same behavior as a node/mask not intersecting cpuset.mems). Migration - relocation of pages to/from a private node: - mbind(MPOL_MF_MOVE) - move_pages() - migrate_pages() mbind(MPOL_MF_MOVE) is a migration, so mempolicy and migration share a single opt-in control. The migration interfaces all check node eligibility and use ALLOC_ZONELIST_PRIVATE to allow eligible migration requests to move a folio to a private node.. alloc_migration_target() carries mtc->zlsel into the allocator via __folio_alloc_zonelist(). Signed-off-by: Gregory Price <[email protected]> --- include/linux/node_private.h | 33 +++++++++++++++++++++++++++++++++ mm/internal.h | 1 + mm/mempolicy.c | 27 ++++++++++++++++++++------- mm/migrate.c | 19 ++++++++++++++----- 4 files changed, 68 insertions(+), 12 deletions(-) diff --git a/include/linux/node_private.h b/include/linux/node_private.h index f7cbae1309904..655fe9ec5cb61 100644 --- a/include/linux/node_private.h +++ b/include/linux/node_private.h @@ -13,6 +13,7 @@ struct page; * to let specific services operate on its node. */ #define NODE_PRIVATE_CAP_RECLAIM (1UL << 0) /* allow mm reclaim */ +#define NODE_PRIVATE_CAP_USER_NUMA (1UL << 1) /* allow mempolicy */ /** * struct node_private - Per-node container for N_MEMORY_PRIVATE nodes @@ -69,6 +70,33 @@ static inline bool node_allows_reclaim(int nid) return ret; } +/** + * node_allows_user_numa - may userspace place or migrate memory here? + * @nid: the node to test + * + * Gate all userspace-directed memory operations on a private node. + * - mbind()/set_mempolicy() + * - move_pages()/migrate_pages() + * + * return: true for N_MEMORY and N_MEMORY_PRIVATE with CAP_USER_NUMA. + * false for memoryless or opted-out private node. + */ +static inline bool node_allows_user_numa(int nid) +{ + struct node_private *np; + bool ret; + + if (node_state(nid, N_MEMORY)) + return true; + if (!node_state(nid, N_MEMORY_PRIVATE)) + return false; + rcu_read_lock(); + np = rcu_dereference(NODE_DATA(nid)->node_private); + ret = np && (np->caps & NODE_PRIVATE_CAP_USER_NUMA); + rcu_read_unlock(); + return ret; +} + #else /* !CONFIG_NUMA */ static inline bool folio_is_private_node(struct folio *folio) @@ -91,6 +119,11 @@ static inline bool node_allows_reclaim(int nid) return true; } +static inline bool node_allows_user_numa(int nid) +{ + return true; +} + #endif /* CONFIG_NUMA */ #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG) diff --git a/mm/internal.h b/mm/internal.h index 8329034ae561f..62e68acae08a3 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1250,6 +1250,7 @@ struct migration_target_control { nodemask_t *nmask; gfp_t gfp_mask; enum migrate_reason reason; + unsigned int alloc_flags; }; /* diff --git a/mm/mempolicy.c b/mm/mempolicy.c index a3ffb09897489..fe42a510590a2 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -434,13 +434,14 @@ static int mpol_set_nodemask(struct mempolicy *pol, /* * Private nodes are not in cpuset.mems, so they're always stripped. - * Driver-allocated policies will already have MPOL_F_PRIVATE set, - * if that's the case, add back in the requested set of private nodes. + * Driver-allocated policies (MPOL_F_PRIVATE) and CAP_USER_NUMA private + * nodes should be added back into the nodemask. */ for_each_node_mask(nid, *nodes) { if (!node_is_private(nid)) continue; - if (pol->flags & MPOL_F_PRIVATE) + if ((pol->flags & MPOL_F_PRIVATE) || + node_allows_user_numa(nid)) node_set(nid, nsc->mask2); } @@ -696,7 +697,7 @@ static void queue_folios_pmd(pmd_t *pmd, struct mm_walk *walk) } if (!queue_folio_required(folio, qp)) return; - if (folio_is_private_node(folio)) + if (!node_allows_user_numa(folio_nid(folio))) return; if (!(qp->flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) || !vma_migratable(walk->vma) || @@ -752,7 +753,8 @@ static int queue_folios_pte_range(pmd_t *pmd, unsigned long addr, continue; } folio = vm_normal_folio(vma, addr, ptent); - if (!folio || folio_is_private_managed(folio)) + if (!folio || folio_is_zone_device(folio) || + !node_allows_user_numa(folio_nid(folio))) continue; if (folio_test_large(folio) && max_nr != 1) nr = folio_pte_batch(folio, pte, ptent, max_nr); @@ -827,7 +829,7 @@ static int queue_folios_hugetlb(pte_t *pte, unsigned long hmask, folio = pfn_folio(pte_pfn(ptep)); if (!queue_folio_required(folio, qp)) goto unlock; - if (folio_is_private_node(folio)) + if (!node_allows_user_numa(folio_nid(folio))) goto unlock; if (!(flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) || !vma_migratable(walk->vma)) { @@ -1412,6 +1414,8 @@ static long migrate_to_node(struct mm_struct *mm, int source, int dest, .nid = dest, .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, .reason = MR_SYSCALL, + .alloc_flags = node_is_private(dest) ? + ALLOC_ZONELIST_PRIVATE : ALLOC_DEFAULT, }; nodes_clear(nmask); @@ -1985,9 +1989,10 @@ static int kernel_migrate_pages(pid_t pid, unsigned long maxnode, struct mm_struct *mm = NULL; struct task_struct *task; nodemask_t task_nodes; - int err; + nodemask_t priv_ok; nodemask_t *old; nodemask_t *new; + int err, nid; NODEMASK_SCRATCH(scratch); if (!scratch) @@ -2027,7 +2032,14 @@ static int kernel_migrate_pages(pid_t pid, unsigned long maxnode, } rcu_read_unlock(); + /* Private nodes are stripped by cpuset checks. Allow eligible ones. */ + nodes_clear(priv_ok); + for_each_node_mask(nid, *new) + if (node_is_private(nid) && node_allows_user_numa(nid)) + node_set(nid, priv_ok); + task_nodes = cpuset_mems_allowed(task); + nodes_or(task_nodes, task_nodes, priv_ok); /* Is the user allowed to access the target nodes? */ if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) { err = -EPERM; @@ -2035,6 +2047,7 @@ static int kernel_migrate_pages(pid_t pid, unsigned long maxnode, } task_nodes = cpuset_mems_allowed(current); + nodes_or(task_nodes, task_nodes, priv_ok); if (!nodes_and(*new, *new, task_nodes)) goto out_put; diff --git a/mm/migrate.c b/mm/migrate.c index d20674c07b947..b548d79352a38 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2231,7 +2231,8 @@ struct folio *alloc_migration_target(struct folio *src, unsigned long private) if (is_highmem_idx(zidx) || zidx == ZONE_MOVABLE) gfp_mask |= __GFP_HIGHMEM; - return __folio_alloc(gfp_mask, order, nid, mtc->nmask, ALLOC_DEFAULT); + return __folio_alloc(gfp_mask, order, nid, mtc->nmask, + mtc->alloc_flags); } #ifdef CONFIG_NUMA_MIGRATION @@ -2253,6 +2254,8 @@ static int do_move_pages_to_node(struct list_head *pagelist, int node) .nid = node, .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, .reason = MR_SYSCALL, + .alloc_flags = node_is_private(node) ? + ALLOC_ZONELIST_PRIVATE : ALLOC_DEFAULT, }; err = migrate_pages(pagelist, alloc_migration_target, NULL, @@ -2268,7 +2271,8 @@ static int __add_folio_for_migration(struct folio *folio, int node, if (is_zero_folio(folio) || is_huge_zero_folio(folio)) return -EFAULT; - if (folio_is_private_managed(folio)) + if (folio_is_zone_device(folio) || + !node_allows_user_numa(folio_nid(folio))) return -ENOENT; if (folio_nid(folio) == node) @@ -2392,11 +2396,14 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, err = -ENODEV; if (node < 0 || node >= MAX_NUMNODES) goto out_flush; - if (!node_state(node, N_MEMORY)) + + if (!node_allows_user_numa(node)) goto out_flush; err = -EACCES; - if (!node_isset(node, task_nodes)) + /* Private nodes are not partitioned by cpuset.mem */ + if (!node_is_private(node) && + !node_isset(node, task_nodes)) goto out_flush; if (current_node == NUMA_NO_NODE) { @@ -2477,7 +2484,9 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, if (folio) { if (is_zero_folio(folio) || is_huge_zero_folio(folio)) err = -EFAULT; - else if (folio_is_private_managed(folio)) + else if (folio_is_zone_device(folio) || + (folio_is_private_node(folio) && + !node_allows_user_numa(folio_nid(folio)))) err = -ENOENT; else err = folio_nid(folio); -- 2.53.0-Meta
