From 58730ab6c7cab4e8525b7492ac369ccbfff5093a Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Wed, 31 Aug 2022 11:19:51 +0800 Subject: [PATCH] ksm: convert to use common struct mm_slot Convert to use common struct mm_slot, no functional change. Link: https://lkml.kernel.org/r/20220831031951.43152-8-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Mike Rapoport Cc: Minchan Kim Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/ksm.c | 132 +++++++++++++++++++++++-------------------------------- 1 file changed, 56 insertions(+), 76 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index 9300e7a48e88..c3edb5836a44 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -42,6 +42,7 @@ #include #include "internal.h" +#include "mm_slot.h" #ifdef CONFIG_NUMA #define NUMA(x) (x) @@ -113,16 +114,12 @@ /** * struct ksm_mm_slot - ksm information per mm that is being scanned - * @hash: link to the mm_slots hash list - * @mm_node: link into the mm_slots list, rooted in ksm_mm_head + * @slot: hash lookup from mm to mm_slot * @rmap_list: head for this mm_slot's singly-linked list of rmap_items - * @mm: the mm that this information is valid for */ struct ksm_mm_slot { - struct hlist_node hash; - struct list_head mm_node; + struct mm_slot slot; struct ksm_rmap_item *rmap_list; - struct mm_struct *mm; }; /** @@ -231,7 +228,7 @@ static LIST_HEAD(migrate_nodes); static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); static struct ksm_mm_slot ksm_mm_head = { - .mm_node = LIST_HEAD_INIT(ksm_mm_head.mm_node), + .slot.mm_node = LIST_HEAD_INIT(ksm_mm_head.slot.mm_node), }; static struct ksm_scan ksm_scan = { .mm_slot = &ksm_mm_head, @@ -409,36 +406,6 @@ static inline void free_stable_node(struct ksm_stable_node *stable_node) kmem_cache_free(stable_node_cache, stable_node); } -static inline struct ksm_mm_slot *alloc_mm_slot(void) -{ - if (!mm_slot_cache) /* initialization failed */ - return NULL; - return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); -} - -static inline void free_mm_slot(struct ksm_mm_slot *mm_slot) -{ - kmem_cache_free(mm_slot_cache, mm_slot); -} - -static struct ksm_mm_slot *get_mm_slot(struct mm_struct *mm) -{ - struct ksm_mm_slot *slot; - - hash_for_each_possible(mm_slots_hash, slot, hash, (unsigned long)mm) - if (slot->mm == mm) - return slot; - - return NULL; -} - -static void insert_to_mm_slots_hash(struct mm_struct *mm, - struct ksm_mm_slot *mm_slot) -{ - mm_slot->mm = mm; - hash_add(mm_slots_hash, &mm_slot->hash, (unsigned long)mm); -} - /* * ksmd, and unmerge_and_remove_all_rmap_items(), must not touch an mm's * page tables after it has passed through ksm_exit() - which, if necessary, @@ -976,20 +943,22 @@ static int remove_all_stable_nodes(void) static int unmerge_and_remove_all_rmap_items(void) { struct ksm_mm_slot *mm_slot; + struct mm_slot *slot; struct mm_struct *mm; struct vm_area_struct *vma; int err = 0; spin_lock(&ksm_mmlist_lock); - ksm_scan.mm_slot = list_entry(ksm_mm_head.mm_node.next, - struct ksm_mm_slot, mm_node); + slot = list_entry(ksm_mm_head.slot.mm_node.next, + struct mm_slot, mm_node); + ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot); spin_unlock(&ksm_mmlist_lock); for (mm_slot = ksm_scan.mm_slot; mm_slot != &ksm_mm_head; mm_slot = ksm_scan.mm_slot) { - VMA_ITERATOR(vmi, mm_slot->mm, 0); + VMA_ITERATOR(vmi, mm_slot->slot.mm, 0); - mm = mm_slot->mm; + mm = mm_slot->slot.mm; mmap_read_lock(mm); for_each_vma(vmi, vma) { if (ksm_test_exit(mm)) @@ -1006,14 +975,15 @@ static int unmerge_and_remove_all_rmap_items(void) mmap_read_unlock(mm); spin_lock(&ksm_mmlist_lock); - ksm_scan.mm_slot = list_entry(mm_slot->mm_node.next, - struct ksm_mm_slot, mm_node); + slot = list_entry(mm_slot->slot.mm_node.next, + struct mm_slot, mm_node); + ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot); if (ksm_test_exit(mm)) { - hash_del(&mm_slot->hash); - list_del(&mm_slot->mm_node); + hash_del(&mm_slot->slot.hash); + list_del(&mm_slot->slot.mm_node); spin_unlock(&ksm_mmlist_lock); - free_mm_slot(mm_slot); + mm_slot_free(mm_slot_cache, mm_slot); clear_bit(MMF_VM_MERGEABLE, &mm->flags); mmdrop(mm); } else @@ -2235,7 +2205,7 @@ static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, rmap_item = alloc_rmap_item(); if (rmap_item) { /* It has already been zeroed */ - rmap_item->mm = mm_slot->mm; + rmap_item->mm = mm_slot->slot.mm; rmap_item->mm->ksm_rmap_items++; rmap_item->address = addr; rmap_item->rmap_list = *rmap_list; @@ -2247,17 +2217,18 @@ static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) { struct mm_struct *mm; - struct ksm_mm_slot *slot; + struct ksm_mm_slot *mm_slot; + struct mm_slot *slot; struct vm_area_struct *vma; struct ksm_rmap_item *rmap_item; struct vma_iterator vmi; int nid; - if (list_empty(&ksm_mm_head.mm_node)) + if (list_empty(&ksm_mm_head.slot.mm_node)) return NULL; - slot = ksm_scan.mm_slot; - if (slot == &ksm_mm_head) { + mm_slot = ksm_scan.mm_slot; + if (mm_slot == &ksm_mm_head) { /* * A number of pages can hang around indefinitely on per-cpu * pagevecs, raised page count preventing write_protect_page @@ -2294,20 +2265,23 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) root_unstable_tree[nid] = RB_ROOT; spin_lock(&ksm_mmlist_lock); - slot = list_entry(slot->mm_node.next, struct ksm_mm_slot, mm_node); - ksm_scan.mm_slot = slot; + slot = list_entry(mm_slot->slot.mm_node.next, + struct mm_slot, mm_node); + mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot); + ksm_scan.mm_slot = mm_slot; spin_unlock(&ksm_mmlist_lock); /* * Although we tested list_empty() above, a racing __ksm_exit * of the last mm on the list may have removed it since then. */ - if (slot == &ksm_mm_head) + if (mm_slot == &ksm_mm_head) return NULL; next_mm: ksm_scan.address = 0; - ksm_scan.rmap_list = &slot->rmap_list; + ksm_scan.rmap_list = &mm_slot->rmap_list; } + slot = &mm_slot->slot; mm = slot->mm; vma_iter_init(&vmi, mm, ksm_scan.address); @@ -2337,7 +2311,7 @@ next_mm: if (PageAnon(*page)) { flush_anon_page(vma, *page, ksm_scan.address); flush_dcache_page(*page); - rmap_item = get_next_rmap_item(slot, + rmap_item = get_next_rmap_item(mm_slot, ksm_scan.rmap_list, ksm_scan.address); if (rmap_item) { ksm_scan.rmap_list = @@ -2358,7 +2332,7 @@ next_page: if (ksm_test_exit(mm)) { no_vmas: ksm_scan.address = 0; - ksm_scan.rmap_list = &slot->rmap_list; + ksm_scan.rmap_list = &mm_slot->rmap_list; } /* * Nuke all the rmap_items that are above this current rmap: @@ -2367,8 +2341,9 @@ no_vmas: remove_trailing_rmap_items(ksm_scan.rmap_list); spin_lock(&ksm_mmlist_lock); - ksm_scan.mm_slot = list_entry(slot->mm_node.next, - struct ksm_mm_slot, mm_node); + slot = list_entry(mm_slot->slot.mm_node.next, + struct mm_slot, mm_node); + ksm_scan.mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot); if (ksm_scan.address == 0) { /* * We've completed a full scan of all vmas, holding mmap_lock @@ -2379,11 +2354,11 @@ no_vmas: * or when all VM_MERGEABLE areas have been unmapped (and * mmap_lock then protects against race with MADV_MERGEABLE). */ - hash_del(&slot->hash); - list_del(&slot->mm_node); + hash_del(&mm_slot->slot.hash); + list_del(&mm_slot->slot.mm_node); spin_unlock(&ksm_mmlist_lock); - free_mm_slot(slot); + mm_slot_free(mm_slot_cache, mm_slot); clear_bit(MMF_VM_MERGEABLE, &mm->flags); mmap_read_unlock(mm); mmdrop(mm); @@ -2400,8 +2375,8 @@ no_vmas: } /* Repeat until we've completed scanning the whole list */ - slot = ksm_scan.mm_slot; - if (slot != &ksm_mm_head) + mm_slot = ksm_scan.mm_slot; + if (mm_slot != &ksm_mm_head) goto next_mm; ksm_scan.seqnr++; @@ -2429,7 +2404,7 @@ static void ksm_do_scan(unsigned int scan_npages) static int ksmd_should_run(void) { - return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.mm_node); + return (ksm_run & KSM_RUN_MERGE) && !list_empty(&ksm_mm_head.slot.mm_node); } static int ksm_scan_thread(void *nothing) @@ -2519,17 +2494,20 @@ EXPORT_SYMBOL_GPL(ksm_madvise); int __ksm_enter(struct mm_struct *mm) { struct ksm_mm_slot *mm_slot; + struct mm_slot *slot; int needs_wakeup; - mm_slot = alloc_mm_slot(); + mm_slot = mm_slot_alloc(mm_slot_cache); if (!mm_slot) return -ENOMEM; + slot = &mm_slot->slot; + /* Check ksm_run too? Would need tighter locking */ - needs_wakeup = list_empty(&ksm_mm_head.mm_node); + needs_wakeup = list_empty(&ksm_mm_head.slot.mm_node); spin_lock(&ksm_mmlist_lock); - insert_to_mm_slots_hash(mm, mm_slot); + mm_slot_insert(mm_slots_hash, mm, slot); /* * When KSM_RUN_MERGE (or KSM_RUN_STOP), * insert just behind the scanning cursor, to let the area settle @@ -2541,9 +2519,9 @@ int __ksm_enter(struct mm_struct *mm) * missed: then we might as well insert at the end of the list. */ if (ksm_run & KSM_RUN_UNMERGE) - list_add_tail(&mm_slot->mm_node, &ksm_mm_head.mm_node); + list_add_tail(&slot->mm_node, &ksm_mm_head.slot.mm_node); else - list_add_tail(&mm_slot->mm_node, &ksm_scan.mm_slot->mm_node); + list_add_tail(&slot->mm_node, &ksm_scan.mm_slot->slot.mm_node); spin_unlock(&ksm_mmlist_lock); set_bit(MMF_VM_MERGEABLE, &mm->flags); @@ -2558,6 +2536,7 @@ int __ksm_enter(struct mm_struct *mm) void __ksm_exit(struct mm_struct *mm) { struct ksm_mm_slot *mm_slot; + struct mm_slot *slot; int easy_to_free = 0; /* @@ -2570,21 +2549,22 @@ void __ksm_exit(struct mm_struct *mm) */ spin_lock(&ksm_mmlist_lock); - mm_slot = get_mm_slot(mm); + slot = mm_slot_lookup(mm_slots_hash, mm); + mm_slot = mm_slot_entry(slot, struct ksm_mm_slot, slot); if (mm_slot && ksm_scan.mm_slot != mm_slot) { if (!mm_slot->rmap_list) { - hash_del(&mm_slot->hash); - list_del(&mm_slot->mm_node); + hash_del(&slot->hash); + list_del(&slot->mm_node); easy_to_free = 1; } else { - list_move(&mm_slot->mm_node, - &ksm_scan.mm_slot->mm_node); + list_move(&slot->mm_node, + &ksm_scan.mm_slot->slot.mm_node); } } spin_unlock(&ksm_mmlist_lock); if (easy_to_free) { - free_mm_slot(mm_slot); + mm_slot_free(mm_slot_cache, mm_slot); clear_bit(MMF_VM_MERGEABLE, &mm->flags); mmdrop(mm); } else if (mm_slot) {