From: Christian Marangi Date: Mon, 22 May 2023 00:36:35 +0000 (+0200) Subject: generic: 6.1: manually refresh mglru patch with new kernel version X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=e41466edab3302b5c667341a06b9fead6eb3436a;p=openwrt%2Fstaging%2Fblogic.git generic: 6.1: manually refresh mglru patch with new kernel version Refresh mglru patch for new kernel version due to very fun backport changing name from folio to pages. Signed-off-by: Christian Marangi --- diff --git a/target/linux/generic/backport-6.1/020-v6.3-19-mm-add-vma_has_recency.patch b/target/linux/generic/backport-6.1/020-v6.3-19-mm-add-vma_has_recency.patch index d740c5bd1d51..eb0181301c54 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-19-mm-add-vma_has_recency.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-19-mm-add-vma_has_recency.patch @@ -58,9 +58,9 @@ Signed-off-by: Andrew Morton --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h -@@ -333,4 +333,13 @@ static __always_inline void del_page_fro - update_lru_size(lruvec, page_lru(page), page_zonenum(page), - -thp_nr_pages(page)); +@@ -606,5 +606,13 @@ static __always_inline void del_page_fro + make_pte_marker(PTE_MARKER_UFFD_WP)); + #endif } + +static inline bool vma_has_recency(struct vm_area_struct *vma) @@ -70,18 +70,10 @@ Signed-off-by: Andrew Morton + + return true; +} -+ + #endif --- a/mm/memory.c +++ b/mm/memory.c -@@ -41,6 +41,7 @@ - - #include - #include -+#include - #include - #include - #include @@ -1353,8 +1354,7 @@ again: force_flush = 1; set_page_dirty(page); @@ -121,10 +113,10 @@ Signed-off-by: Andrew Morton - /* - * Don't treat a reference through - * a sequentially read mapping as such. -- * If the page has been used in another mapping, +- * If the folio has been used in another mapping, - * we will catch it; if this other mapping is - * already gone, the unmap path will have set -- * PG_referenced or activated the page. +- * the referenced flag or activated the folio. - */ - if (likely(!(vma->vm_flags & VM_SEQ_READ))) - referenced++; @@ -157,10 +149,10 @@ Signed-off-by: Andrew Morton return false; @@ -876,6 +878,7 @@ int page_referenced(struct page *page, - .rmap_one = page_referenced_one, .arg = (void *)&pra, - .anon_lock = page_lock_anon_vma_read, -+ .invalid_vma = invalid_page_referenced_vma, + .anon_lock = folio_lock_anon_vma_read, + .try_lock = true, ++ .invalid_vma = invalid_folio_referenced_vma, }; *vm_flags = 0; @@ -174,10 +166,10 @@ Signed-off-by: Andrew Morton - * cgroups - */ - if (memcg) { -- rwc.invalid_vma = invalid_page_referenced_vma; +- rwc.invalid_vma = invalid_folio_referenced_vma; - } - - rmap_walk(page, &rwc); + rmap_walk(folio, &rwc); *vm_flags = pra.vm_flags; --- a/mm/vmscan.c diff --git a/target/linux/generic/backport-6.1/020-v6.3-21-mm-multi-gen-LRU-rename-lru_gen_struct-to-lru_gen_pa.patch b/target/linux/generic/backport-6.1/020-v6.3-21-mm-multi-gen-LRU-rename-lru_gen_struct-to-lru_gen_pa.patch index 4e09173681fb..960661a0e65a 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-21-mm-multi-gen-LRU-rename-lru_gen_struct-to-lru_gen_pa.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-21-mm-multi-gen-LRU-rename-lru_gen_struct-to-lru_gen_pa.patch @@ -2,7 +2,7 @@ From 348fdbada9fb3f0bf1a53651be46319105af187f Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Wed, 21 Dec 2022 21:18:59 -0700 Subject: [PATCH 21/29] mm: multi-gen LRU: rename lru_gen_struct to - lru_gen_page + lru_gen_folio Patch series "mm: multi-gen LRU: memcg LRU", v3. @@ -10,7 +10,7 @@ Overview ======== An memcg LRU is a per-node LRU of memcgs. It is also an LRU of LRUs, -since each node and memcg combination has an LRU of pages (see +since each node and memcg combination has an LRU of folios (see mem_cgroup_lruvec()). Its goal is to improve the scalability of global reclaim, which is @@ -24,7 +24,7 @@ the worst-case complexity O(n). Therefore, on average, it has a sublinear complexity in contrast to the current linear complexity. The basic structure of an memcg LRU can be understood by an analogy to -the active/inactive LRU (of pages): +the active/inactive LRU (of folios): 1. It has the young and the old (generations), i.e., the counterparts to the active and the inactive; 2. The increment of max_seq triggers promotion, i.e., the counterpart @@ -101,7 +101,7 @@ The following is a simple test to quickly verify its effectiveness. This patch (of 8): -The new name lru_gen_page will be more distinct from the coming +The new name lru_gen_folio will be more distinct from the coming lru_gen_memcg. Link: https://lkml.kernel.org/r/20221222041905.2431096-1-yuzhao@google.com @@ -125,31 +125,31 @@ Signed-off-by: Andrew Morton --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -168,7 +168,7 @@ static inline void lru_gen_update_size(s - int zone = page_zonenum(page); - int delta = thp_nr_pages(page); + int zone = folio_zonenum(folio); + int delta = thp_nr_folios(folio); enum lru_list lru = type * LRU_INACTIVE_FILE; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; VM_WARN_ON_ONCE(old_gen != -1 && old_gen >= MAX_NR_GENS); VM_WARN_ON_ONCE(new_gen != -1 && new_gen >= MAX_NR_GENS); -@@ -214,7 +214,7 @@ static inline bool lru_gen_add_page(stru - int gen = page_lru_gen(page); - int type = page_is_file_lru(page); - int zone = page_zonenum(page); +@@ -214,7 +214,7 @@ static inline bool lru_gen_add_folio(stru + int gen = folio_lru_gen(folio); + int type = folio_is_file_lru(folio); + int zone = folio_zonenum(folio); - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; - VM_WARN_ON_ONCE_PAGE(gen != -1, page); + VM_WARN_ON_ONCE_FOLIO(gen != -1, folio); --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -394,7 +394,7 @@ enum { - * The number of pages in each generation is eventually consistent and therefore + * The number of folios in each generation is eventually consistent and therefore * can be transiently negative when reset_batch_size() is pending. */ -struct lru_gen_struct { -+struct lru_gen_page { ++struct lru_gen_folio { /* the aging increments the youngest generation number */ unsigned long max_seq; /* the eviction increments the oldest generation numbers */ @@ -158,7 +158,7 @@ Signed-off-by: Andrew Morton /* the lruvec under reclaim */ struct lruvec *lruvec; - /* unstable max_seq from lru_gen_struct */ -+ /* unstable max_seq from lru_gen_page */ ++ /* unstable max_seq from lru_gen_folio */ unsigned long max_seq; /* the next address within an mm to scan */ unsigned long next_addr; @@ -167,7 +167,7 @@ Signed-off-by: Andrew Morton #ifdef CONFIG_LRU_GEN /* evictable pages divided into generations */ - struct lru_gen_struct lrugen; -+ struct lru_gen_page lrugen; ++ struct lru_gen_folio lrugen; /* to concurrently iterate lru_gen_mm_list */ struct lru_gen_mm_state mm_state; #endif @@ -178,7 +178,7 @@ Signed-off-by: Andrew Morton static bool __maybe_unused seq_is_valid(struct lruvec *lruvec) { - /* see the comment on lru_gen_struct */ -+ /* see the comment on lru_gen_page */ ++ /* see the comment on lru_gen_folio */ return get_nr_gens(lruvec, LRU_GEN_FILE) >= MIN_NR_GENS && get_nr_gens(lruvec, LRU_GEN_FILE) <= get_nr_gens(lruvec, LRU_GEN_ANON) && get_nr_gens(lruvec, LRU_GEN_ANON) <= MAX_NR_GENS; @@ -187,7 +187,7 @@ Signed-off-by: Andrew Morton struct ctrl_pos *pos) { - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; int hist = lru_hist_from_seq(lrugen->min_seq[type]); pos->refaulted = lrugen->avg_refaulted[type][tier] + @@ -196,25 +196,25 @@ Signed-off-by: Andrew Morton { int hist, tier; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; bool clear = carryover ? NR_HIST_GENS == 1 : NR_HIST_GENS > 1; unsigned long seq = carryover ? lrugen->min_seq[type] : lrugen->max_seq + 1; -@@ -3408,7 +3408,7 @@ static int page_update_gen(struct page * - static int page_inc_gen(struct lruvec *lruvec, struct page *page, bool reclaiming) +@@ -3408,7 +3408,7 @@ static int folio_update_gen(struct folio * + static int folio_inc_gen(struct lruvec *lruvec, struct folio *folio, bool reclaiming) { - int type = page_is_file_lru(page); + int type = folio_is_file_lru(folio); - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]); - unsigned long new_flags, old_flags = READ_ONCE(page->flags); + unsigned long new_flags, old_flags = READ_ONCE(folio->flags); @@ -3453,7 +3453,7 @@ static void update_batch_size(struct lru static void reset_batch_size(struct lruvec *lruvec, struct lru_gen_mm_walk *walk) { int gen, type, zone; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; walk->batched = 0; @@ -223,7 +223,7 @@ Signed-off-by: Andrew Morton int zone; int remaining = MAX_LRU_BATCH; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; int new_gen, old_gen = lru_gen_from_seq(lrugen->min_seq[type]); if (type == LRU_GEN_ANON && !can_swap) @@ -232,7 +232,7 @@ Signed-off-by: Andrew Morton int gen, type, zone; bool success = false; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; DEFINE_MIN_SEQ(lruvec); VM_WARN_ON_ONCE(!seq_is_valid(lruvec)); @@ -241,7 +241,7 @@ Signed-off-by: Andrew Morton } - /* see the comment on lru_gen_struct */ -+ /* see the comment on lru_gen_page */ ++ /* see the comment on lru_gen_folio */ if (can_swap) { min_seq[LRU_GEN_ANON] = min(min_seq[LRU_GEN_ANON], min_seq[LRU_GEN_FILE]); min_seq[LRU_GEN_FILE] = max(min_seq[LRU_GEN_ANON], lrugen->min_seq[LRU_GEN_FILE]); @@ -250,7 +250,7 @@ Signed-off-by: Andrew Morton int prev, next; int type, zone; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; spin_lock_irq(&lruvec->lru_lock); @@ -259,7 +259,7 @@ Signed-off-by: Andrew Morton struct lru_gen_mm_walk *walk; struct mm_struct *mm = NULL; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; VM_WARN_ON_ONCE(max_seq > READ_ONCE(lrugen->max_seq)); @@ -268,25 +268,25 @@ Signed-off-by: Andrew Morton unsigned long young = 0; unsigned long total = 0; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; struct mem_cgroup *memcg = lruvec_memcg(lruvec); for (type = !can_swap; type < ANON_AND_FILE; type++) { -@@ -4466,7 +4466,7 @@ static bool sort_page(struct lruvec *lru - int delta = thp_nr_pages(page); - int refs = page_lru_refs(page); +@@ -4466,7 +4466,7 @@ static bool sort_folio(struct lruvec *lru + int delta = thp_nr_folios(folio); + int refs = folio_lru_refs(folio); int tier = lru_tier_from_refs(refs); - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; - VM_WARN_ON_ONCE_PAGE(gen >= MAX_NR_GENS, page); + VM_WARN_ON_ONCE_folio(gen >= MAX_NR_GENS, folio); -@@ -4566,7 +4566,7 @@ static int scan_pages(struct lruvec *lru +@@ -4566,7 +4566,7 @@ static int scan_folios(struct lruvec *lru int scanned = 0; int isolated = 0; int remaining = MAX_LRU_BATCH; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; struct mem_cgroup *memcg = lruvec_memcg(lruvec); VM_WARN_ON_ONCE(!list_empty(list)); @@ -295,7 +295,7 @@ Signed-off-by: Andrew Morton static bool __maybe_unused state_is_valid(struct lruvec *lruvec) { - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; if (lrugen->enabled) { enum lru_list lru; @@ -304,7 +304,7 @@ Signed-off-by: Andrew Morton int type, tier; int hist = lru_hist_from_seq(seq); - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; for (tier = 0; tier < MAX_NR_TIERS; tier++) { seq_printf(m, " %10d", tier); @@ -313,7 +313,7 @@ Signed-off-by: Andrew Morton bool full = !debugfs_real_fops(m->file)->write; struct lruvec *lruvec = v; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; int nid = lruvec_pgdat(lruvec)->node_id; struct mem_cgroup *memcg = lruvec_memcg(lruvec); DEFINE_MAX_SEQ(lruvec); @@ -322,7 +322,7 @@ Signed-off-by: Andrew Morton int i; int gen, type, zone; - struct lru_gen_struct *lrugen = &lruvec->lrugen; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; lrugen->max_seq = MIN_NR_GENS + 1; lrugen->enabled = lru_gen_enabled(); @@ -333,16 +333,16 @@ Signed-off-by: Andrew Morton unsigned long min_seq; struct lruvec *lruvec; - struct lru_gen_struct *lrugen; -+ struct lru_gen_page *lrugen; - int type = page_is_file_lru(page); - int delta = thp_nr_pages(page); - int refs = page_lru_refs(page); -@@ -252,7 +252,7 @@ static void lru_gen_refault(struct page ++ struct lru_gen_folio *lrugen; + int type = folio_is_file_lru(folio); + int delta = thp_nr_folios(folio); + int refs = folio_lru_refs(folio); +@@ -252,7 +252,7 @@ static void lru_gen_refault(struct folio unsigned long token; unsigned long min_seq; struct lruvec *lruvec; - struct lru_gen_struct *lrugen; -+ struct lru_gen_page *lrugen; ++ struct lru_gen_folio *lrugen; struct mem_cgroup *memcg; struct pglist_data *pgdat; - int type = page_is_file_lru(page); + int type = folio_is_file_lru(folio); diff --git a/target/linux/generic/backport-6.1/020-v6.3-22-mm-multi-gen-LRU-rename-lrugen-lists-to-lrugen-pages.patch b/target/linux/generic/backport-6.1/020-v6.3-22-mm-multi-gen-LRU-rename-lrugen-lists-to-lrugen-pages.patch index b548c1c8b3de..32b7b39f69a4 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-22-mm-multi-gen-LRU-rename-lrugen-lists-to-lrugen-pages.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-22-mm-multi-gen-LRU-rename-lrugen-lists-to-lrugen-pages.patch @@ -2,9 +2,9 @@ From afd37e73db04c7e6b47411120ac5f6a7eca51fec Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Wed, 21 Dec 2022 21:19:00 -0700 Subject: [PATCH 22/29] mm: multi-gen LRU: rename lrugen->lists[] to - lrugen->pages[] + lrugen->folios[] -lru_gen_page will be chained into per-node lists by the coming +lru_gen_folio will be chained into per-node lists by the coming lrugen->list. Link: https://lkml.kernel.org/r/20221222041905.2431096-3-yuzhao@google.com @@ -25,15 +25,15 @@ Signed-off-by: Andrew Morton --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h -@@ -246,9 +246,9 @@ static inline bool lru_gen_add_page(stru - lru_gen_update_size(lruvec, page, -1, gen); - /* for rotate_reclaimable_page() */ +@@ -246,9 +246,9 @@ static inline bool lru_gen_add_folio(stru + lru_gen_update_size(lruvec, folio, -1, gen); + /* for rotate_reclaimable_folio() */ if (reclaiming) -- list_add_tail(&page->lru, &lrugen->lists[gen][type][zone]); -+ list_add_tail(&page->lru, &lrugen->pages[gen][type][zone]); +- list_add_tail(&folio->lru, &lrugen->lists[gen][type][zone]); ++ list_add_tail(&folio->lru, &lrugen->folios[gen][type][zone]); else -- list_add(&page->lru, &lrugen->lists[gen][type][zone]); -+ list_add(&page->lru, &lrugen->pages[gen][type][zone]); +- list_add(&folio->lru, &lrugen->lists[gen][type][zone]); ++ list_add(&folio->lru, &lrugen->folios[gen][type][zone]); return true; } @@ -42,31 +42,31 @@ Signed-off-by: Andrew Morton @@ -302,7 +302,7 @@ enum lruvec_flags { * They form a sliding window of a variable size [MIN_NR_GENS, MAX_NR_GENS]. An * offset within MAX_NR_GENS, i.e., gen, indexes the LRU list of the - * corresponding generation. The gen counter in page->flags stores gen+1 while + * corresponding generation. The gen counter in folio->flags stores gen+1 while - * a page is on one of lrugen->lists[]. Otherwise it stores 0. -+ * a page is on one of lrugen->pages[]. Otherwise it stores 0. ++ * a page is on one of lrugen->folios[]. Otherwise it stores 0. * - * A page is added to the youngest generation on faulting. The aging needs to - * check the accessed bit at least twice before handing this page over to the + * A folio is added to the youngest generation on faulting. The aging needs to + * check the accessed bit at least twice before handing this folio over to the @@ -314,8 +314,8 @@ enum lruvec_flags { * rest of generations, if they exist, are considered inactive. See * lru_gen_is_active(). * - * PG_active is always cleared while a page is on one of lrugen->lists[] so that - * the aging needs not to worry about it. And it's set again when a page -+ * PG_active is always cleared while a page is on one of lrugen->pages[] so ++ * PG_active is always cleared while a page is on one of lrugen->folios[] so + * that the aging needs not to worry about it. And it's set again when a page * considered active is isolated for non-reclaiming purposes, e.g., migration. - * See lru_gen_add_page() and lru_gen_del_page(). + * See lru_gen_add_folio() and lru_gen_del_folio(). * -@@ -402,7 +402,7 @@ struct lru_gen_page { +@@ -402,7 +402,7 @@ struct lru_gen_folio { /* the birth time of each generation in jiffies */ unsigned long timestamps[MAX_NR_GENS]; /* the multi-gen LRU lists, lazily sorted on eviction */ - struct list_head lists[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES]; -+ struct list_head pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES]; ++ struct list_head folios[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES]; /* the multi-gen LRU sizes, eventually consistent */ - long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES]; + long nr_folios[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES]; /* the exponential moving average of refaulted */ --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -75,16 +75,16 @@ Signed-off-by: Andrew Morton /* prevent cold/hot inversion if force_scan is true */ for (zone = 0; zone < MAX_NR_ZONES; zone++) { - struct list_head *head = &lrugen->lists[old_gen][type][zone]; -+ struct list_head *head = &lrugen->pages[old_gen][type][zone]; ++ struct list_head *head = &lrugen->folios[old_gen][type][zone]; while (!list_empty(head)) { - struct page *page = lru_to_page(head); + struct folio *folio = lru_to_folio(head); @@ -3998,7 +3998,7 @@ static bool inc_min_seq(struct lruvec *l - VM_WARN_ON_ONCE_PAGE(page_zonenum(page) != zone, page); + VM_WARN_ON_ONCE_folio(folio_zonenum(folio) != zone, folio); - new_gen = page_inc_gen(lruvec, page, false); -- list_move_tail(&page->lru, &lrugen->lists[new_gen][type][zone]); -+ list_move_tail(&page->lru, &lrugen->pages[new_gen][type][zone]); + new_gen = folio_inc_gen(lruvec, folio, false); +- list_move_tail(&folio->lru, &lrugen->lists[new_gen][type][zone]); ++ list_move_tail(&folio->lru, &lrugen->folios[new_gen][type][zone]); if (!--remaining) return false; @@ -93,52 +93,52 @@ Signed-off-by: Andrew Morton for (zone = 0; zone < MAX_NR_ZONES; zone++) { - if (!list_empty(&lrugen->lists[gen][type][zone])) -+ if (!list_empty(&lrugen->pages[gen][type][zone])) ++ if (!list_empty(&lrugen->folios[gen][type][zone])) goto next; } -@@ -4491,7 +4491,7 @@ static bool sort_page(struct lruvec *lru +@@ -4491,7 +4491,7 @@ static bool sort_folio(struct lruvec *lru /* promoted */ if (gen != lru_gen_from_seq(lrugen->min_seq[type])) { -- list_move(&page->lru, &lrugen->lists[gen][type][zone]); -+ list_move(&page->lru, &lrugen->pages[gen][type][zone]); +- list_move(&folio->lru, &lrugen->lists[gen][type][zone]); ++ list_move(&folio->lru, &lrugen->folios[gen][type][zone]); return true; } -@@ -4500,7 +4500,7 @@ static bool sort_page(struct lruvec *lru +@@ -4500,7 +4500,7 @@ static bool sort_folio(struct lruvec *lru int hist = lru_hist_from_seq(lrugen->min_seq[type]); - gen = page_inc_gen(lruvec, page, false); -- list_move_tail(&page->lru, &lrugen->lists[gen][type][zone]); -+ list_move_tail(&page->lru, &lrugen->pages[gen][type][zone]); + gen = folio_inc_gen(lruvec, folio, false); +- list_move_tail(&folio->lru, &lrugen->lists[gen][type][zone]); ++ list_move_tail(&folio->lru, &lrugen->folios[gen][type][zone]); WRITE_ONCE(lrugen->protected[hist][type][tier - 1], lrugen->protected[hist][type][tier - 1] + delta); -@@ -4512,7 +4512,7 @@ static bool sort_page(struct lruvec *lru - if (PageLocked(page) || PageWriteback(page) || - (type == LRU_GEN_FILE && PageDirty(page))) { - gen = page_inc_gen(lruvec, page, true); -- list_move(&page->lru, &lrugen->lists[gen][type][zone]); -+ list_move(&page->lru, &lrugen->pages[gen][type][zone]); +@@ -4512,7 +4512,7 @@ static bool sort_folio(struct lruvec *lru + if (folioLocked(folio) || folioWriteback(folio) || + (type == LRU_GEN_FILE && folioDirty(folio))) { + gen = folio_inc_gen(lruvec, folio, true); +- list_move(&folio->lru, &lrugen->lists[gen][type][zone]); ++ list_move(&folio->lru, &lrugen->folios[gen][type][zone]); return true; } -@@ -4579,7 +4579,7 @@ static int scan_pages(struct lruvec *lru +@@ -4579,7 +4579,7 @@ static int scan_folios(struct lruvec *lru for (zone = sc->reclaim_idx; zone >= 0; zone--) { LIST_HEAD(moved); int skipped = 0; - struct list_head *head = &lrugen->lists[gen][type][zone]; -+ struct list_head *head = &lrugen->pages[gen][type][zone]; ++ struct list_head *head = &lrugen->folios[gen][type][zone]; while (!list_empty(head)) { - struct page *page = lru_to_page(head); + struct folio *folio = lru_to_folio(head); @@ -4980,7 +4980,7 @@ static bool __maybe_unused state_is_vali int gen, type, zone; for_each_gen_type_zone(gen, type, zone) { - if (!list_empty(&lrugen->lists[gen][type][zone])) -+ if (!list_empty(&lrugen->pages[gen][type][zone])) ++ if (!list_empty(&lrugen->folios[gen][type][zone])) return false; } } @@ -147,7 +147,7 @@ Signed-off-by: Andrew Morton for_each_gen_type_zone(gen, type, zone) { - struct list_head *head = &lruvec->lrugen.lists[gen][type][zone]; -+ struct list_head *head = &lruvec->lrugen.pages[gen][type][zone]; ++ struct list_head *head = &lruvec->lrugen.folios[gen][type][zone]; while (!list_empty(head)) { bool success; @@ -156,7 +156,7 @@ Signed-off-by: Andrew Morton for_each_gen_type_zone(gen, type, zone) - INIT_LIST_HEAD(&lrugen->lists[gen][type][zone]); -+ INIT_LIST_HEAD(&lrugen->pages[gen][type][zone]); ++ INIT_LIST_HEAD(&lrugen->folios[gen][type][zone]); lruvec->mm_state.seq = MIN_NR_GENS; init_waitqueue_head(&lruvec->mm_state.wait); diff --git a/target/linux/generic/backport-6.1/020-v6.3-23-mm-multi-gen-LRU-remove-eviction-fairness-safeguard.patch b/target/linux/generic/backport-6.1/020-v6.3-23-mm-multi-gen-LRU-remove-eviction-fairness-safeguard.patch index 2bb6e12a5ae1..01babfecb1e5 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-23-mm-multi-gen-LRU-remove-eviction-fairness-safeguard.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-23-mm-multi-gen-LRU-remove-eviction-fairness-safeguard.patch @@ -4,7 +4,7 @@ Date: Wed, 21 Dec 2022 21:19:01 -0700 Subject: [PATCH 23/29] mm: multi-gen LRU: remove eviction fairness safeguard Recall that the eviction consumes the oldest generation: first it -bucket-sorts pages whose gen counters were updated by the aging and +bucket-sorts folios whose gen counters were updated by the aging and reclaims the rest; then it increments lrugen->min_seq. The current eviction fairness safeguard for global reclaim has a @@ -61,13 +61,13 @@ Signed-off-by: Andrew Morton static bool writeback_throttling_sane(struct scan_control *sc) { return true; -@@ -4722,8 +4732,7 @@ static int isolate_pages(struct lruvec * +@@ -4722,8 +4732,7 @@ static int isolate_folios(struct lruvec * return scanned; } --static int evict_pages(struct lruvec *lruvec, struct scan_control *sc, int swappiness, -- bool *need_swapping) -+static int evict_pages(struct lruvec *lruvec, struct scan_control *sc, int swappiness) +-static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swappiness, +- bool *need_swapping) ++static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swappiness) { int type; int scanned; @@ -81,7 +81,7 @@ Signed-off-by: Andrew Morton return scanned; } -@@ -4853,68 +4859,26 @@ done: +@@ -4853,67 +4859,26 @@ done: return min_seq[!can_swap] + MIN_NR_GENS <= max_seq ? nr_to_scan : 0; } @@ -93,7 +93,7 @@ Signed-off-by: Andrew Morton - DEFINE_MAX_SEQ(lruvec); - - if (!current_is_kswapd()) { -- /* age each memcg once to ensure fairness */ +- /* age each memcg at most once to ensure fairness */ - if (max_seq - seq > 1) - return true; - @@ -118,10 +118,9 @@ Signed-off-by: Andrew Morton - - /* - * A minimum amount of work was done under global memory pressure. For -- * kswapd, it may be overshooting. For direct reclaim, the target isn't -- * met, and yet the allocation may still succeed, since kswapd may have -- * caught up. In either case, it's better to stop now, and restart if -- * necessary. +- * kswapd, it may be overshooting. For direct reclaim, the allocation +- * may succeed if all suitable zones are somewhat safe. In either case, +- * it's better to stop now, and restart later if necessary. - */ - for (i = 0; i <= sc->reclaim_idx; i++) { - unsigned long wmark; @@ -163,8 +162,8 @@ Signed-off-by: Andrew Morton if (!nr_to_scan) goto done; -- delta = evict_pages(lruvec, sc, swappiness, &need_swapping); -+ delta = evict_pages(lruvec, sc, swappiness); +- delta = evict_folios(lruvec, sc, swappiness, &need_swapping); ++ delta = evict_folios(lruvec, sc, swappiness); if (!delta) goto done; @@ -181,8 +180,8 @@ Signed-off-by: Andrew Morton if (sc->nr_reclaimed >= nr_to_reclaim) return 0; -- if (!evict_pages(lruvec, sc, swappiness, NULL)) -+ if (!evict_pages(lruvec, sc, swappiness)) +- if (!evict_folios(lruvec, sc, swappiness, NULL)) ++ if (!evict_folios(lruvec, sc, swappiness)) return 0; cond_resched(); diff --git a/target/linux/generic/backport-6.1/020-v6.3-24-mm-multi-gen-LRU-remove-aging-fairness-safeguard.patch b/target/linux/generic/backport-6.1/020-v6.3-24-mm-multi-gen-LRU-remove-aging-fairness-safeguard.patch index 316217ed028d..2f4fb911f5b5 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-24-mm-multi-gen-LRU-remove-aging-fairness-safeguard.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-24-mm-multi-gen-LRU-remove-aging-fairness-safeguard.patch @@ -4,13 +4,13 @@ Date: Wed, 21 Dec 2022 21:19:02 -0700 Subject: [PATCH 24/29] mm: multi-gen LRU: remove aging fairness safeguard Recall that the aging produces the youngest generation: first it scans -for accessed pages and updates their gen counters; then it increments +for accessed folios and updates their gen counters; then it increments lrugen->max_seq. The current aging fairness safeguard for kswapd uses two passes to ensure the fairness to multiple eligible memcgs. On the first pass, which is shared with the eviction, it checks whether all eligible -memcgs are low on cold pages. If so, it requires a second pass, on +memcgs are low on cold folios. If so, it requires a second pass, on which it ages all those memcgs at the same time. With memcg LRU, the aging, while ensuring eventual fairness, will run @@ -56,11 +56,11 @@ Signed-off-by: Andrew Morton int gen, type, zone; @@ -4193,6 +4192,13 @@ static bool should_run_aging(struct lruv unsigned long total = 0; - struct lru_gen_page *lrugen = &lruvec->lrugen; + struct lru_gen_folio *lrugen = &lruvec->lrugen; struct mem_cgroup *memcg = lruvec_memcg(lruvec); + DEFINE_MIN_SEQ(lruvec); + -+ /* whether this lruvec is completely out of cold pages */ ++ /* whether this lruvec is completely out of cold folios */ + if (min_seq[!can_swap] + MIN_NR_GENS > max_seq) { + *nr_to_scan = 0; + return true; @@ -90,7 +90,7 @@ Signed-off-by: Andrew Morton + int gen, type, zone; + unsigned long total = 0; + bool can_swap = get_swappiness(lruvec, sc); -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; struct mem_cgroup *memcg = lruvec_memcg(lruvec); DEFINE_MAX_SEQ(lruvec); DEFINE_MIN_SEQ(lruvec); @@ -134,7 +134,7 @@ Signed-off-by: Andrew Morton - if (!nr_to_scan && sc->priority != DEF_PRIORITY) - return false; - } -+ /* see the comment on lru_gen_page */ ++ /* see the comment on lru_gen_folio */ + gen = lru_gen_from_seq(min_seq[LRU_GEN_FILE]); + birth = READ_ONCE(lruvec->lrugen.timestamps[gen]); @@ -242,7 +242,7 @@ Signed-off-by: Andrew Morton - return nr_to_scan; -done: - return min_seq[!can_swap] + MIN_NR_GENS <= max_seq ? nr_to_scan : 0; -+ /* skip this lruvec as it's low on cold pages */ ++ /* skip this lruvec as it's low on cold folios */ + return 0; } @@ -267,7 +267,7 @@ Signed-off-by: Andrew Morton - goto done; + break; - delta = evict_pages(lruvec, sc, swappiness); + delta = evict_folios(lruvec, sc, swappiness); if (!delta) - goto done; + break; diff --git a/target/linux/generic/backport-6.1/020-v6.3-25-mm-multi-gen-LRU-shuffle-should_run_aging.patch b/target/linux/generic/backport-6.1/020-v6.3-25-mm-multi-gen-LRU-shuffle-should_run_aging.patch index 391ee6e67cea..2e6b8b9c9b25 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-25-mm-multi-gen-LRU-shuffle-should_run_aging.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-25-mm-multi-gen-LRU-shuffle-should_run_aging.patch @@ -32,11 +32,11 @@ Signed-off-by: Andrew Morton - unsigned long old = 0; - unsigned long young = 0; - unsigned long total = 0; -- struct lru_gen_page *lrugen = &lruvec->lrugen; +- struct lru_gen_folio *lrugen = &lruvec->lrugen; - struct mem_cgroup *memcg = lruvec_memcg(lruvec); - DEFINE_MIN_SEQ(lruvec); - -- /* whether this lruvec is completely out of cold pages */ +- /* whether this lruvec is completely out of cold folios */ - if (min_seq[!can_swap] + MIN_NR_GENS > max_seq) { - *nr_to_scan = 0; - return true; @@ -101,11 +101,11 @@ Signed-off-by: Andrew Morton + unsigned long old = 0; + unsigned long young = 0; + unsigned long total = 0; -+ struct lru_gen_page *lrugen = &lruvec->lrugen; ++ struct lru_gen_folio *lrugen = &lruvec->lrugen; + struct mem_cgroup *memcg = lruvec_memcg(lruvec); + DEFINE_MIN_SEQ(lruvec); + -+ /* whether this lruvec is completely out of cold pages */ ++ /* whether this lruvec is completely out of cold folios */ + if (min_seq[!can_swap] + MIN_NR_GENS > max_seq) { + *nr_to_scan = 0; + return true; diff --git a/target/linux/generic/backport-6.1/020-v6.3-26-mm-multi-gen-LRU-per-node-lru_gen_page-lists.patch b/target/linux/generic/backport-6.1/020-v6.3-26-mm-multi-gen-LRU-per-node-lru_gen_page-lists.patch index f54e828de106..5aa7473c21b2 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-26-mm-multi-gen-LRU-per-node-lru_gen_page-lists.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-26-mm-multi-gen-LRU-per-node-lru_gen_page-lists.patch @@ -1,7 +1,7 @@ From fa6363828d314e837c5f79e97ea5e8c0d2f7f062 Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Wed, 21 Dec 2022 21:19:04 -0700 -Subject: [PATCH 26/29] mm: multi-gen LRU: per-node lru_gen_page lists +Subject: [PATCH 26/29] mm: multi-gen LRU: per-node lru_gen_folio lists For each node, memcgs are divided into two generations: the old and the young. For each generation, memcgs are randomly sharded into @@ -63,7 +63,7 @@ Signed-off-by: Andrew Morton include/linux/mm_inline.h | 17 ++ include/linux/mmzone.h | 117 +++++++++++- mm/memcontrol.c | 16 ++ - mm/page_alloc.c | 1 + + mm/folio_alloc.c | 1 + mm/vmscan.c | 373 +++++++++++++++++++++++++++++++++---- 6 files changed, 499 insertions(+), 35 deletions(-) @@ -123,7 +123,7 @@ Signed-off-by: Andrew Morton + return 0; +} + - static inline bool lru_gen_add_page(struct lruvec *lruvec, struct page *page, bool reclaiming) + static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio, bool reclaiming) { return false; --- a/include/linux/mmzone.h @@ -136,7 +136,7 @@ Signed-off-by: Andrew Morton #include #include #include -@@ -357,6 +358,15 @@ struct page_vma_mapped_walk; +@@ -357,6 +358,15 @@ struct folio_vma_mapped_walk; #define LRU_GEN_MASK ((BIT(LRU_GEN_WIDTH) - 1) << LRU_GEN_PGOFF) #define LRU_REFS_MASK ((BIT(LRU_REFS_WIDTH) - 1) << LRU_REFS_PGOFF) @@ -152,16 +152,16 @@ Signed-off-by: Andrew Morton #ifdef CONFIG_LRU_GEN enum { -@@ -416,6 +426,14 @@ struct lru_gen_page { +@@ -416,6 +426,14 @@ struct lru_gen_folio { atomic_long_t refaulted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS]; /* whether the multi-gen LRU is enabled */ bool enabled; +#ifdef CONFIG_MEMCG -+ /* the memcg generation this lru_gen_page belongs to */ ++ /* the memcg generation this lru_gen_folio belongs to */ + u8 gen; -+ /* the list segment this lru_gen_page belongs to */ ++ /* the list segment this lru_gen_folio belongs to */ + u8 seg; -+ /* per-node lru_gen_page list for global reclaim */ ++ /* per-node lru_gen_folio list for global reclaim */ + struct hlist_nulls_node list; +#endif }; @@ -216,9 +216,9 @@ Signed-off-by: Andrew Morton +struct lru_gen_memcg { + /* the per-node memcg generation counter */ + unsigned long seq; -+ /* each memcg has one lru_gen_page per node */ ++ /* each memcg has one lru_gen_folio per node */ + unsigned long nr_memcgs[MEMCG_NR_GENS]; -+ /* per-node lru_gen_page list for global reclaim */ ++ /* per-node lru_gen_folio list for global reclaim */ + struct hlist_nulls_head fifo[MEMCG_NR_GENS][MEMCG_NR_BINS]; + /* protects the above */ + spinlock_t lock; @@ -294,7 +294,7 @@ Signed-off-by: Andrew Morton #ifdef CONFIG_LRU_GEN /* kswap mm walk data */ struct lru_gen_mm_walk mm_walk; -+ /* lru_gen_page list */ ++ /* lru_gen_folio list */ + struct lru_gen_memcg memcg_lru; #endif @@ -306,7 +306,7 @@ Signed-off-by: Andrew Morton struct mem_cgroup_tree_per_node *mctz; + if (lru_gen_enabled()) { -+ struct lruvec *lruvec = &mem_cgroup_page_nodeinfo(memcg, page)->lruvec; ++ struct lruvec *lruvec = &memcg->nodeinfo[nid]->lruvec; + + /* see the comment on MEMCG_NR_GENS */ + if (soft_limit_excess(memcg) && lru_gen_memcg_seg(lruvec) != MEMCG_LRU_HEAD) @@ -315,7 +315,7 @@ Signed-off-by: Andrew Morton + return; + } + - mctz = soft_limit_tree_from_page(page); + mctz = soft_limit_tree.rb_tree_per_node[nid]; if (!mctz) return; @@ -3433,6 +3443,9 @@ unsigned long mem_cgroup_soft_limit_recl @@ -430,7 +430,7 @@ Signed-off-by: Andrew Morton - try_to_inc_max_seq(lruvec, max_seq, sc, can_swap, false); - - /* skip this lruvec as it's low on cold pages */ + /* skip this lruvec as it's low on cold folios */ - return 0; + return try_to_inc_max_seq(lruvec, max_seq, sc, can_swap, false) ? -1 : 0; } @@ -476,7 +476,7 @@ Signed-off-by: Andrew Morton + if (nr_to_scan <= 0) break; - delta = evict_pages(lruvec, sc, swappiness); + delta = evict_folios(lruvec, sc, swappiness); @@ -4912,10 +4895,250 @@ static void lru_gen_shrink_lruvec(struct cond_resched(); } @@ -532,7 +532,7 @@ Signed-off-by: Andrew Morton + int bin; + int first_bin; + struct lruvec *lruvec; -+ struct lru_gen_page *lrugen; ++ struct lru_gen_folio *lrugen; + const struct hlist_nulls_node *pos; + int op = 0; + struct mem_cgroup *memcg = NULL; diff --git a/target/linux/generic/backport-6.1/020-v6.3-27-mm-multi-gen-LRU-clarify-scan_control-flags.patch b/target/linux/generic/backport-6.1/020-v6.3-27-mm-multi-gen-LRU-clarify-scan_control-flags.patch index 882f29e98922..029141b2d3e1 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-27-mm-multi-gen-LRU-clarify-scan_control-flags.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-27-mm-multi-gen-LRU-clarify-scan_control-flags.patch @@ -10,10 +10,10 @@ Among the flags in scan_control: opportunistically skip the aging path, since it is considered less latency sensitive. 3. !(sc->gfp_mask & __GFP_IO), which indicates IO constraint, lowers - swappiness to prioritize file LRU, since clean file pages are more + swappiness to prioritize file LRU, since clean file folios are more likely to exist. -4. sc->may_writepage and sc->may_unmap, which indicates opportunistic - reclaim, are rejected, since unmapped clean pages are already +4. sc->may_writefolio and sc->may_unmap, which indicates opportunistic + reclaim, are rejected, since unmapped clean folios are already prioritized. Scanning for more of them is likely futile and can cause high reclaim latency when there is a large number of memcgs. @@ -43,7 +43,7 @@ Signed-off-by: Andrew Morton + return 0; + if (!can_demote(pgdat->node_id, sc) && - mem_cgroup_get_nr_swap_pages(memcg) < MIN_LRU_BATCH) + mem_cgroup_get_nr_swap_folios(memcg) < MIN_LRU_BATCH) return 0; @@ -3952,7 +3955,7 @@ static void walk_mm(struct lruvec *lruve } while (err == -EAGAIN); @@ -78,24 +78,24 @@ Signed-off-by: Andrew Morton - VM_WARN_ON_ONCE(sc->memcg_low_reclaim); - - /* see the comment on lru_gen_page */ + /* see the comment on lru_gen_folio */ gen = lru_gen_from_seq(min_seq[LRU_GEN_FILE]); birth = READ_ONCE(lruvec->lrugen.timestamps[gen]); -@@ -4472,12 +4473,8 @@ static bool isolate_page(struct lruvec * +@@ -4472,12 +4473,8 @@ static bool isolate_folio(struct lruvec * { bool success; - /* unmapping inhibited */ -- if (!sc->may_unmap && page_mapped(page)) +- if (!sc->may_unmap && folio_mapped(folio)) - return false; - /* swapping inhibited */ - if (!(sc->may_writepage && (sc->gfp_mask & __GFP_IO)) && + if (!(sc->gfp_mask & __GFP_IO) && - (PageDirty(page) || - (PageAnon(page) && !PageSwapCache(page)))) + (folio_test_dirty(folio) || + (folio_test_anon(folio) && !folio_test_swapcache(folio)))) return false; -@@ -4574,9 +4571,8 @@ static int scan_pages(struct lruvec *lru +@@ -4574,9 +4571,8 @@ static int scan_folios(struct lruvec *lru __count_vm_events(PGSCAN_ANON + type, isolated); /* @@ -123,7 +123,7 @@ Signed-off-by: Andrew Morton unsigned long nr_to_reclaim = get_nr_to_reclaim(sc); + int swappiness = get_swappiness(lruvec, sc); + -+ /* clean file pages are more likely to exist */ ++ /* clean file folios are more likely to exist */ + if (swappiness && !(sc->gfp_mask & __GFP_IO)) + swappiness = 1; @@ -151,7 +151,7 @@ Signed-off-by: Andrew Morton blk_start_plug(&plug); - set_mm_walk(lruvec_pgdat(lruvec)); -+ set_mm_walk(NULL, false); ++ set_mm_walk(NULL, sc->proactive); if (try_to_shrink_lruvec(lruvec, sc)) lru_gen_rotate_memcg(lruvec, MEMCG_LRU_YOUNG); @@ -160,7 +160,7 @@ Signed-off-by: Andrew Morton VM_WARN_ON_ONCE(!global_reclaim(sc)); + /* -+ * Unmapped clean pages are already prioritized. Scanning for more of ++ * Unmapped clean folios are already prioritized. Scanning for more of + * them is likely futile and can cause high reclaim latency when there + * is a large number of memcgs. + */ @@ -172,7 +172,7 @@ Signed-off-by: Andrew Morton blk_start_plug(&plug); - set_mm_walk(pgdat); -+ set_mm_walk(pgdat, false); ++ set_mm_walk(NULL, sc->proactive); set_initial_priority(pgdat, sc); diff --git a/target/linux/generic/backport-6.1/020-v6.3-29-mm-multi-gen-LRU-avoid-futile-retries.patch b/target/linux/generic/backport-6.1/020-v6.3-29-mm-multi-gen-LRU-avoid-futile-retries.patch index 2d19d0d7da18..62904e165535 100644 --- a/target/linux/generic/backport-6.1/020-v6.3-29-mm-multi-gen-LRU-avoid-futile-retries.patch +++ b/target/linux/generic/backport-6.1/020-v6.3-29-mm-multi-gen-LRU-avoid-futile-retries.patch @@ -34,7 +34,7 @@ Signed-off-by: Andrew Morton int bin; int first_bin; struct lruvec *lruvec; - struct lru_gen_page *lrugen; + struct lru_gen_folio *lrugen; + struct mem_cgroup *memcg; const struct hlist_nulls_node *pos; - int op = 0;