From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B47B5C4332F for ; Wed, 18 May 2022 01:47:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233829AbiERBr0 (ORCPT ); Tue, 17 May 2022 21:47:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231903AbiERBrS (ORCPT ); Tue, 17 May 2022 21:47:18 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D4DC546BA for ; Tue, 17 May 2022 18:47:02 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id z39-20020a25a12a000000b0064dbcd526ffso668449ybh.15 for ; Tue, 17 May 2022 18:47:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc:content-transfer-encoding; bh=BdUc2XW5WiYZ2PyvxlGy/bO/1gRq+jLxJ6Cnbh8ZRtg=; b=qhdyQyyqKmnnf8W0m9OZi2oQ/MrcdAZ/SMOU/6RU5cNGVey0Jy/4RETmNFMqktRUkr 7gRVPaF8+cwHyZyBfbTaInVUSLGeyWxIRCaJbNT0TmcUwOWH5i6EwHDIX78bKm6jll0z sMjEwNCnVNnEOvKV1yNCNHeCz2kq+WmPXGxxfCId9UoaHhnSS0vgBj+jk0ze79ZfDXln 095FKO8g96C1bITtbSSq5b43ArRm8aENU2jqYM35EM0OOuT3QNM9jp8eAIXLWcAZIswx VJFSFevIl/MxIjSSbUloc6omWd3cZlgET2OWyas4ME80t9FXYJMnWn50msgLaE+L/PxR oHmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc:content-transfer-encoding; bh=BdUc2XW5WiYZ2PyvxlGy/bO/1gRq+jLxJ6Cnbh8ZRtg=; b=phqC22lx50WKN+oZgww37wAK4cfE5USyLwuJU1WTNkbQ7v6Cye4whNHqEQ1Ao6+rnd aHCHoWyIyEo7ZI/RgxF5TWKOApu70MwQA/l3awYTyy7qGYW2I7MJpucKqFs0L7YG+E3Q uErGyh3+Zbxd23llOI5alakh8PoWJq1FoZaVfvLzOVb6HLNY736YkWQznifgpVLI5WyV 17shAOxOsJQvFI7v3PhLYjLlZ+85Un3LxuPOCTxALhGzjh0WbYKkSY9hk9L92LxUg8zd 38tqyMm+LVOMRqKNb0t3Owi3XqatvN1B12+MtfN1XYTXvcYFs9p28nzqKR45Ekiw3CvN mR/w== X-Gm-Message-State: AOAM53383v5MoUhAkLJodt42EOywo0/TfwKqnflQjZ3DMvep86sETQks CtJbtKbI3nEM4L/L7RLoZTOrQQzODt0= X-Google-Smtp-Source: ABdhPJzi5vnU5GSPs3vkYq8/ubKvEppWjlekA5su3Hj5yutoUD7xax3AXYkTquX943inyyuVqfA7ffiBesU= X-Received: from yuzhao.bld.corp.google.com ([2620:15c:183:200:f7bc:90c9:d86e:4ea8]) (user=yuzhao job=sendgmr) by 2002:a81:25d3:0:b0:2ff:111c:a5ce with SMTP id l202-20020a8125d3000000b002ff111ca5cemr10934053ywl.372.1652838421629; Tue, 17 May 2022 18:47:01 -0700 (PDT) Date: Tue, 17 May 2022 19:46:24 -0600 In-Reply-To: <20220518014632.922072-1-yuzhao@google.com> Message-Id: <20220518014632.922072-6-yuzhao@google.com> Mime-Version: 1.0 References: <20220518014632.922072-1-yuzhao@google.com> X-Mailer: git-send-email 2.36.0.550.gb090851708-goog Subject: [PATCH v11 05/14] mm: multi-gen LRU: groundwork From: Yu Zhao To: Andrew Morton , linux-mm@kvack.org Cc: Andi Kleen , Aneesh Kumar , Catalin Marinas , Dave Hansen , Hillf Danton , Jens Axboe , Johannes Weiner , Jonathan Corbet , Linus Torvalds , Matthew Wilcox , Mel Gorman , Michael Larabel , Michal Hocko , Mike Rapoport , Peter Zijlstra , Tejun Heo , Vlastimil Babka , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, page-reclaim@google.com, Yu Zhao , Brian Geffon , Jan Alexander Steffens , Oleksandr Natalenko , Steven Barrett , Suleiman Souhlal , Daniel Byrne , Donald Carr , "=?UTF-8?q?Holger=20Hoffst=C3=A4tte?=" , Konstantin Kharlamov , Shuang Zhai , Sofia Trinh , Vaibhav Jain Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Evictable pages are divided into multiple generations for each lruvec. The youngest generation number is stored in lrugen->max_seq for both anon and file types as they are aged on an equal footing. The oldest generation numbers are stored in lrugen->min_seq[] separately for anon and file types as clean file pages can be evicted regardless of swap constraints. These three variables are monotonically increasing. Generation numbers are truncated into order_base_2(MAX_NR_GENS+1) bits in order to fit into the gen counter in folio->flags. Each truncated generation number is an index to lrugen->lists[]. The sliding window technique is used to track at least MIN_NR_GENS and at most MAX_NR_GENS generations. The gen counter stores a value within [1, MAX_NR_GENS] while a page is on one of lrugen->lists[]. Otherwise it stores 0. There are two conceptually independent procedures: "the aging", which produces young generations, and "the eviction", which consumes old generations. They form a closed-loop system, i.e., "the page reclaim". Both procedures can be invoked from userspace for the purposes of working set estimation and proactive reclaim. These techniques are commonly used to optimize job scheduling (bin packing) in data centers [1][2]. To avoid confusion, the terms "hot" and "cold" will be applied to the multi-gen LRU, as a new convention; the terms "active" and "inactive" will be applied to the active/inactive LRU, as usual. The protection of hot pages and the selection of cold pages are based on page access channels and patterns. There are two access channels: one through page tables and the other through file descriptors. The protection of the former channel is by design stronger because: 1. The uncertainty in determining the access patterns of the former channel is higher due to the approximation of the accessed bit. 2. The cost of evicting the former channel is higher due to the TLB flushes required and the likelihood of encountering the dirty bit. 3. The penalty of underprotecting the former channel is higher because applications usually do not prepare themselves for major page faults like they do for blocked I/O. E.g., GUI applications commonly use dedicated I/O threads to avoid blocking the rendering threads. There are also two access patterns: one with temporal locality and the other without. For the reasons listed above, the former channel is assumed to follow the former pattern unless VM_SEQ_READ or VM_RAND_READ is present; the latter channel is assumed to follow the latter pattern unless outlying refaults have been observed [3][4]. The next patch will address the "outlying refaults". Three macros, i.e., LRU_REFS_WIDTH, LRU_REFS_PGOFF and LRU_REFS_MASK, used later are added in this patch to make the entire patchset less diffy. 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 eviction. The first check takes care of the accessed bit set on the initial fault; the second check makes sure this page has not been used since then. This protocol, AKA second chance, requires a minimum of two generations, hence MIN_NR_GENS. [1] https://dl.acm.org/doi/10.1145/3297858.3304053 [2] https://dl.acm.org/doi/10.1145/3503222.3507731 [3] https://lwn.net/Articles/495543/ [4] https://lwn.net/Articles/815342/ Signed-off-by: Yu Zhao Acked-by: Brian Geffon Acked-by: Jan Alexander Steffens (heftig) Acked-by: Oleksandr Natalenko Acked-by: Steven Barrett Acked-by: Suleiman Souhlal Tested-by: Daniel Byrne Tested-by: Donald Carr Tested-by: Holger Hoffst=C3=A4tte Tested-by: Konstantin Kharlamov Tested-by: Shuang Zhai Tested-by: Sofia Trinh Tested-by: Vaibhav Jain --- fs/fuse/dev.c | 3 +- include/linux/mm.h | 2 + include/linux/mm_inline.h | 180 ++++++++++++++++++++++++++++++ include/linux/mmzone.h | 98 ++++++++++++++++ include/linux/page-flags-layout.h | 13 ++- include/linux/page-flags.h | 4 +- include/linux/sched.h | 4 + kernel/bounds.c | 5 + mm/Kconfig | 8 ++ mm/huge_memory.c | 3 +- mm/memcontrol.c | 2 + mm/memory.c | 25 +++++ mm/mm_init.c | 6 +- mm/mmzone.c | 2 + mm/swap.c | 9 +- mm/vmscan.c | 75 +++++++++++++ 16 files changed, 426 insertions(+), 13 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 0e537e580dc1..5d36015071d2 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -777,7 +777,8 @@ static int fuse_check_page(struct page *page) 1 << PG_active | 1 << PG_workingset | 1 << PG_reclaim | - 1 << PG_waiters))) { + 1 << PG_waiters | + LRU_GEN_MASK | LRU_REFS_MASK))) { dump_page(page, "fuse: trying to steal weird page"); return 1; } diff --git a/include/linux/mm.h b/include/linux/mm.h index 9f44254af8ce..894c289c2c06 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1060,6 +1060,8 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf)= ; #define ZONES_PGOFF (NODES_PGOFF - ZONES_WIDTH) #define LAST_CPUPID_PGOFF (ZONES_PGOFF - LAST_CPUPID_WIDTH) #define KASAN_TAG_PGOFF (LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH) +#define LRU_GEN_PGOFF (KASAN_TAG_PGOFF - LRU_GEN_WIDTH) +#define LRU_REFS_PGOFF (LRU_GEN_PGOFF - LRU_REFS_WIDTH) =20 /* * Define the bit shifts to access each section. For non-existent diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index 7c9c2157e9a8..98ae22bfaf12 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -38,6 +38,9 @@ static __always_inline void __update_lru_size(struct lruv= ec *lruvec, { struct pglist_data *pgdat =3D lruvec_pgdat(lruvec); =20 + lockdep_assert_held(&lruvec->lru_lock); + WARN_ON_ONCE(nr_pages !=3D (int)nr_pages); + __mod_lruvec_state(lruvec, NR_LRU_BASE + lru, nr_pages); __mod_zone_page_state(&pgdat->node_zones[zid], NR_ZONE_LRU_BASE + lru, nr_pages); @@ -99,11 +102,182 @@ static __always_inline enum lru_list folio_lru_list(s= truct folio *folio) return lru; } =20 +#ifdef CONFIG_LRU_GEN + +static inline bool lru_gen_enabled(void) +{ + return true; +} + +static inline bool lru_gen_in_fault(void) +{ + return current->in_lru_fault; +} + +static inline int lru_gen_from_seq(unsigned long seq) +{ + return seq % MAX_NR_GENS; +} + +static inline int folio_lru_gen(struct folio *folio) +{ + unsigned long flags =3D READ_ONCE(folio->flags); + + return ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1; +} + +static inline bool lru_gen_is_active(struct lruvec *lruvec, int gen) +{ + unsigned long max_seq =3D lruvec->lrugen.max_seq; + + VM_WARN_ON_ONCE(gen >=3D MAX_NR_GENS); + + /* see the comment on MIN_NR_GENS */ + return gen =3D=3D lru_gen_from_seq(max_seq) || gen =3D=3D lru_gen_from_se= q(max_seq - 1); +} + +static inline void lru_gen_update_size(struct lruvec *lruvec, struct folio= *folio, + int old_gen, int new_gen) +{ + int type =3D folio_is_file_lru(folio); + int zone =3D folio_zonenum(folio); + int delta =3D folio_nr_pages(folio); + enum lru_list lru =3D type * LRU_INACTIVE_FILE; + struct lru_gen_struct *lrugen =3D &lruvec->lrugen; + + VM_WARN_ON_ONCE(old_gen !=3D -1 && old_gen >=3D MAX_NR_GENS); + VM_WARN_ON_ONCE(new_gen !=3D -1 && new_gen >=3D MAX_NR_GENS); + VM_WARN_ON_ONCE(old_gen =3D=3D -1 && new_gen =3D=3D -1); + + if (old_gen >=3D 0) + WRITE_ONCE(lrugen->nr_pages[old_gen][type][zone], + lrugen->nr_pages[old_gen][type][zone] - delta); + if (new_gen >=3D 0) + WRITE_ONCE(lrugen->nr_pages[new_gen][type][zone], + lrugen->nr_pages[new_gen][type][zone] + delta); + + /* addition */ + if (old_gen < 0) { + if (lru_gen_is_active(lruvec, new_gen)) + lru +=3D LRU_ACTIVE; + __update_lru_size(lruvec, lru, zone, delta); + return; + } + + /* deletion */ + if (new_gen < 0) { + if (lru_gen_is_active(lruvec, old_gen)) + lru +=3D LRU_ACTIVE; + __update_lru_size(lruvec, lru, zone, -delta); + return; + } +} + +static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *= folio, bool reclaiming) +{ + unsigned long mask, flags; + int gen =3D folio_lru_gen(folio); + int type =3D folio_is_file_lru(folio); + int zone =3D folio_zonenum(folio); + struct lru_gen_struct *lrugen =3D &lruvec->lrugen; + + VM_WARN_ON_ONCE_FOLIO(gen !=3D -1, folio); + + if (folio_test_unevictable(folio)) + return false; + /* + * There are three common cases for this page: + * 1. If it's hot, e.g., freshly faulted in or previously hot and + * migrated, add it to the youngest generation. + * 2. If it's cold but can't be evicted immediately, i.e., an anon page + * not in swapcache or a dirty page pending writeback, add it to the + * second oldest generation. + * 3. Everything else (clean, cold) is added to the oldest generation. + */ + if (folio_test_active(folio)) + gen =3D lru_gen_from_seq(lrugen->max_seq); + else if ((type =3D=3D LRU_GEN_ANON && !folio_test_swapcache(folio)) || + (folio_test_reclaim(folio) && + (folio_test_dirty(folio) || folio_test_writeback(folio)))) + gen =3D lru_gen_from_seq(lrugen->min_seq[type] + 1); + else + gen =3D lru_gen_from_seq(lrugen->min_seq[type]); + + /* see the comment on MIN_NR_GENS */ + mask =3D LRU_GEN_MASK | BIT(PG_active); + flags =3D (gen + 1UL) << LRU_GEN_PGOFF; + set_mask_bits(&folio->flags, mask, flags); + + lru_gen_update_size(lruvec, folio, -1, gen); + /* for folio_rotate_reclaimable() */ + if (reclaiming) + list_add_tail(&folio->lru, &lrugen->lists[gen][type][zone]); + else + list_add(&folio->lru, &lrugen->lists[gen][type][zone]); + + return true; +} + +static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *= folio, bool reclaiming) +{ + unsigned long mask, flags; + int gen =3D folio_lru_gen(folio); + + if (gen < 0) + return false; + + VM_WARN_ON_ONCE_FOLIO(folio_test_active(folio), folio); + VM_WARN_ON_ONCE_FOLIO(folio_test_unevictable(folio), folio); + + mask =3D LRU_GEN_MASK; + flags =3D 0; + /* for shrink_page_list() or folio_migrate_flags() */ + if (reclaiming) + mask |=3D BIT(PG_referenced) | BIT(PG_reclaim); + else if (lru_gen_is_active(lruvec, gen)) + flags |=3D BIT(PG_active); + + flags =3D set_mask_bits(&folio->flags, mask, flags); + gen =3D ((flags & LRU_GEN_MASK) >> LRU_GEN_PGOFF) - 1; + + lru_gen_update_size(lruvec, folio, gen, -1); + list_del(&folio->lru); + + return true; +} + +#else + +static inline bool lru_gen_enabled(void) +{ + return false; +} + +static inline bool lru_gen_in_fault(void) +{ + return false; +} + +static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *= folio, bool reclaiming) +{ + return false; +} + +static inline bool lru_gen_del_folio(struct lruvec *lruvec, struct folio *= folio, bool reclaiming) +{ + return false; +} + +#endif /* CONFIG_LRU_GEN */ + static __always_inline void lruvec_add_folio(struct lruvec *lruvec, struct folio *folio) { enum lru_list lru =3D folio_lru_list(folio); =20 + if (lru_gen_add_folio(lruvec, folio, false)) + return; + update_lru_size(lruvec, lru, folio_zonenum(folio), folio_nr_pages(folio)); if (lru !=3D LRU_UNEVICTABLE) @@ -121,6 +295,9 @@ void lruvec_add_folio_tail(struct lruvec *lruvec, struc= t folio *folio) { enum lru_list lru =3D folio_lru_list(folio); =20 + if (lru_gen_add_folio(lruvec, folio, true)) + return; + update_lru_size(lruvec, lru, folio_zonenum(folio), folio_nr_pages(folio)); /* This is not expected to be used on LRU_UNEVICTABLE */ @@ -138,6 +315,9 @@ void lruvec_del_folio(struct lruvec *lruvec, struct fol= io *folio) { enum lru_list lru =3D folio_lru_list(folio); =20 + if (lru_gen_del_folio(lruvec, folio, false)) + return; + if (lru !=3D LRU_UNEVICTABLE) list_del(&folio->lru); update_lru_size(lruvec, lru, folio_zonenum(folio), diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 46ffab808f03..6994acef63cb 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -317,6 +317,100 @@ enum lruvec_flags { */ }; =20 +#endif /* !__GENERATING_BOUNDS_H */ + +/* + * Evictable pages are divided into multiple generations. The youngest and= the + * oldest generation numbers, max_seq and min_seq, are monotonically incre= asing. + * 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 folio->flags stores gen+1 = while + * a page is on one of lrugen->lists[]. 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 + * eviction. The first check takes care of the accessed bit set on the ini= tial + * fault; the second check makes sure this page hasn't been used since the= n. + * This process, AKA second chance, requires a minimum of two generations, + * hence MIN_NR_GENS. And to maintain ABI compatibility with the active/in= active + * LRU, e.g., /proc/vmstat, these two generations are considered active; t= he + * 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 considered active is isolated for non-reclaiming purp= oses, + * e.g., migration. See lru_gen_add_folio() and lru_gen_del_folio(). + * + * MAX_NR_GENS is set to 4 so that the multi-gen LRU can support twice the + * number of categories of the active/inactive LRU when keeping track of + * accesses through page tables. It requires order_base_2(MAX_NR_GENS+1) b= its in + * folio->flags (LRU_GEN_MASK). + */ +#define MIN_NR_GENS 2U +#define MAX_NR_GENS 4U + +#ifndef __GENERATING_BOUNDS_H + +struct lruvec; + +#define LRU_GEN_MASK ((BIT(LRU_GEN_WIDTH) - 1) << LRU_GEN_PGOFF) +#define LRU_REFS_MASK ((BIT(LRU_REFS_WIDTH) - 1) << LRU_REFS_PGOFF) + +#ifdef CONFIG_LRU_GEN + +enum { + LRU_GEN_ANON, + LRU_GEN_FILE, +}; + +/* + * The youngest generation number is stored in max_seq for both anon and f= ile + * types as they are aged on an equal footing. The oldest generation numbe= rs are + * stored in min_seq[] separately for anon and file types as clean file pa= ges + * can be evicted regardless of swap constraints. + * + * Normally anon and file min_seq are in sync. But if swapping is constrai= ned, + * e.g., out of swap space, file min_seq is allowed to advance and leave a= non + * min_seq behind. + * + * nr_pages[] are eventually consistent and therefore can be transiently + * negative. + */ +struct lru_gen_struct { + /* the aging increments the youngest generation number */ + unsigned long max_seq; + /* the eviction increments the oldest generation numbers */ + unsigned long min_seq[ANON_AND_FILE]; + /* the multi-gen LRU lists */ + struct list_head lists[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES]; + /* the sizes of the above lists */ + long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES]; +}; + +void lru_gen_init_lruvec(struct lruvec *lruvec); + +#ifdef CONFIG_MEMCG +void lru_gen_init_memcg(struct mem_cgroup *memcg); +void lru_gen_exit_memcg(struct mem_cgroup *memcg); +#endif + +#else /* !CONFIG_LRU_GEN */ + +static inline void lru_gen_init_lruvec(struct lruvec *lruvec) +{ +} + +#ifdef CONFIG_MEMCG +static inline void lru_gen_init_memcg(struct mem_cgroup *memcg) +{ +} + +static inline void lru_gen_exit_memcg(struct mem_cgroup *memcg) +{ +} +#endif + +#endif /* CONFIG_LRU_GEN */ + struct lruvec { struct list_head lists[NR_LRU_LISTS]; /* per lruvec lru_lock for memcg */ @@ -334,6 +428,10 @@ struct lruvec { unsigned long refaults[ANON_AND_FILE]; /* Various lruvec state flags (enum lruvec_flags) */ unsigned long flags; +#ifdef CONFIG_LRU_GEN + /* evictable pages divided into generations */ + struct lru_gen_struct lrugen; +#endif #ifdef CONFIG_MEMCG struct pglist_data *pgdat; #endif diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-l= ayout.h index ef1e3e736e14..240905407a18 100644 --- a/include/linux/page-flags-layout.h +++ b/include/linux/page-flags-layout.h @@ -55,7 +55,8 @@ #define SECTIONS_WIDTH 0 #endif =20 -#if ZONES_WIDTH + SECTIONS_WIDTH + NODES_SHIFT <=3D BITS_PER_LONG - NR_PAG= EFLAGS +#if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_SHIFT \ + <=3D BITS_PER_LONG - NR_PAGEFLAGS #define NODES_WIDTH NODES_SHIFT #elif defined(CONFIG_SPARSEMEM_VMEMMAP) #error "Vmemmap: No space for nodes field in page flags" @@ -89,8 +90,8 @@ #define LAST_CPUPID_SHIFT 0 #endif =20 -#if ZONES_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + KASAN_TAG_WIDTH + LAST_CP= UPID_SHIFT \ - <=3D BITS_PER_LONG - NR_PAGEFLAGS +#if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \ + KASAN_TAG_WIDTH + LAST_CPUPID_SHIFT <=3D BITS_PER_LONG - NR_PAGEFLAGS #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT #else #define LAST_CPUPID_WIDTH 0 @@ -100,10 +101,12 @@ #define LAST_CPUPID_NOT_IN_PAGE_FLAGS #endif =20 -#if ZONES_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + KASAN_TAG_WIDTH + LAST_CP= UPID_WIDTH \ - > BITS_PER_LONG - NR_PAGEFLAGS +#if ZONES_WIDTH + LRU_GEN_WIDTH + SECTIONS_WIDTH + NODES_WIDTH + \ + KASAN_TAG_WIDTH + LAST_CPUPID_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS #error "Not enough bits in page flags" #endif =20 +#define LRU_REFS_WIDTH 0 + #endif #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 9d8eeaa67d05..5cbde013ce66 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -1017,7 +1017,7 @@ PAGEFLAG(Isolated, isolated, PF_ANY); 1UL << PG_private | 1UL << PG_private_2 | \ 1UL << PG_writeback | 1UL << PG_reserved | \ 1UL << PG_slab | 1UL << PG_active | \ - 1UL << PG_unevictable | __PG_MLOCKED) + 1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK) =20 /* * Flags checked when a page is prepped for return by the page allocator. @@ -1028,7 +1028,7 @@ PAGEFLAG(Isolated, isolated, PF_ANY); * alloc-free cycle to prevent from reusing the page. */ #define PAGE_FLAGS_CHECK_AT_PREP \ - (PAGEFLAGS_MASK & ~__PG_HWPOISON) + ((PAGEFLAGS_MASK & ~__PG_HWPOISON) | LRU_GEN_MASK | LRU_REFS_MASK) =20 #define PAGE_FLAGS_PRIVATE \ (1UL << PG_private | 1UL << PG_private_2) diff --git a/include/linux/sched.h b/include/linux/sched.h index a8911b1f35aa..448e75a5acc5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -914,6 +914,10 @@ struct task_struct { #ifdef CONFIG_MEMCG unsigned in_user_fault:1; #endif +#ifdef CONFIG_LRU_GEN + /* whether the LRU algorithm may apply to this access */ + unsigned in_lru_fault:1; +#endif #ifdef CONFIG_COMPAT_BRK unsigned brk_randomized:1; #endif diff --git a/kernel/bounds.c b/kernel/bounds.c index 9795d75b09b2..5ee60777d8e4 100644 --- a/kernel/bounds.c +++ b/kernel/bounds.c @@ -22,6 +22,11 @@ int main(void) DEFINE(NR_CPUS_BITS, ilog2(CONFIG_NR_CPUS)); #endif DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t)); +#ifdef CONFIG_LRU_GEN + DEFINE(LRU_GEN_WIDTH, order_base_2(MAX_NR_GENS + 1)); +#else + DEFINE(LRU_GEN_WIDTH, 0); +#endif /* End of constants */ =20 return 0; diff --git a/mm/Kconfig b/mm/Kconfig index 034d87953600..e62bd501082b 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -909,6 +909,14 @@ config ANON_VMA_NAME area from being merged with adjacent virtual memory areas due to the difference in their name. =20 +config LRU_GEN + bool "Multi-Gen LRU" + depends on MMU + # make sure folio->flags has enough spare bits + depends on 64BIT || !SPARSEMEM || SPARSEMEM_VMEMMAP + help + A high performance LRU implementation to overcommit memory. + source "mm/damon/Kconfig" =20 endmenu diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 910a138e9859..a090514f2bf3 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2320,7 +2320,8 @@ static void __split_huge_page_tail(struct page *head,= int tail, #ifdef CONFIG_64BIT (1L << PG_arch_2) | #endif - (1L << PG_dirty))); + (1L << PG_dirty) | + LRU_GEN_MASK | LRU_REFS_MASK)); =20 /* ->mapping in first tail page is compound_mapcount */ VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping !=3D TAIL_MAPPING, diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 598fece89e2b..2ee074f80e72 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5072,6 +5072,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memc= g) =20 static void mem_cgroup_free(struct mem_cgroup *memcg) { + lru_gen_exit_memcg(memcg); memcg_wb_domain_exit(memcg); __mem_cgroup_free(memcg); } @@ -5130,6 +5131,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void) memcg->deferred_split_queue.split_queue_len =3D 0; #endif idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); + lru_gen_init_memcg(memcg); return memcg; fail: mem_cgroup_id_remove(memcg); diff --git a/mm/memory.c b/mm/memory.c index 44a1ec7a2cac..6df27b84c5aa 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4812,6 +4812,27 @@ static inline void mm_account_fault(struct pt_regs *= regs, perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, address); } =20 +#ifdef CONFIG_LRU_GEN +static void lru_gen_enter_fault(struct vm_area_struct *vma) +{ + /* the LRU algorithm doesn't apply to sequential or random reads */ + current->in_lru_fault =3D !(vma->vm_flags & (VM_SEQ_READ | VM_RAND_READ))= ; +} + +static void lru_gen_exit_fault(void) +{ + current->in_lru_fault =3D false; +} +#else +static void lru_gen_enter_fault(struct vm_area_struct *vma) +{ +} + +static void lru_gen_exit_fault(void) +{ +} +#endif /* CONFIG_LRU_GEN */ + /* * By the time we get here, we already hold the mm semaphore * @@ -4843,11 +4864,15 @@ vm_fault_t handle_mm_fault(struct vm_area_struct *v= ma, unsigned long address, if (flags & FAULT_FLAG_USER) mem_cgroup_enter_user_fault(); =20 + lru_gen_enter_fault(vma); + if (unlikely(is_vm_hugetlb_page(vma))) ret =3D hugetlb_fault(vma->vm_mm, vma, address, flags); else ret =3D __handle_mm_fault(vma, address, flags); =20 + lru_gen_exit_fault(); + if (flags & FAULT_FLAG_USER) { mem_cgroup_exit_user_fault(); /* diff --git a/mm/mm_init.c b/mm/mm_init.c index 9ddaf0e1b0ab..0d7b2bd2454a 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -65,14 +65,16 @@ void __init mminit_verify_pageflags_layout(void) =20 shift =3D 8 * sizeof(unsigned long); width =3D shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH - - LAST_CPUPID_SHIFT - KASAN_TAG_WIDTH; + - LAST_CPUPID_SHIFT - KASAN_TAG_WIDTH - LRU_GEN_WIDTH - LRU_REFS_WIDTH; mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths", - "Section %d Node %d Zone %d Lastcpupid %d Kasantag %d Flags %d\n", + "Section %d Node %d Zone %d Lastcpupid %d Kasantag %d Gen %d Tier %d Fla= gs %d\n", SECTIONS_WIDTH, NODES_WIDTH, ZONES_WIDTH, LAST_CPUPID_WIDTH, KASAN_TAG_WIDTH, + LRU_GEN_WIDTH, + LRU_REFS_WIDTH, NR_PAGEFLAGS); mminit_dprintk(MMINIT_TRACE, "pageflags_layout_shifts", "Section %d Node %d Zone %d Lastcpupid %d Kasantag %d\n", diff --git a/mm/mmzone.c b/mm/mmzone.c index 0ae7571e35ab..68e1511be12d 100644 --- a/mm/mmzone.c +++ b/mm/mmzone.c @@ -88,6 +88,8 @@ void lruvec_init(struct lruvec *lruvec) * Poison its list head, so that any operations on it would crash. */ list_del(&lruvec->lists[LRU_UNEVICTABLE]); + + lru_gen_init_lruvec(lruvec); } =20 #if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLA= GS) diff --git a/mm/swap.c b/mm/swap.c index 7e320ec08c6a..a6870ba0bd83 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -460,6 +460,11 @@ void folio_add_lru(struct folio *folio) VM_BUG_ON_FOLIO(folio_test_active(folio) && folio_test_unevictable(folio)= , folio); VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); =20 + /* see the comment in lru_gen_add_folio() */ + if (lru_gen_enabled() && !folio_test_unevictable(folio) && + lru_gen_in_fault() && !(current->flags & PF_MEMALLOC)) + folio_set_active(folio); + folio_get(folio); local_lock(&lru_pvecs.lock); pvec =3D this_cpu_ptr(&lru_pvecs.lru_add); @@ -551,7 +556,7 @@ static void lru_deactivate_file_fn(struct page *page, s= truct lruvec *lruvec) =20 static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec) { - if (PageActive(page) && !PageUnevictable(page)) { + if (!PageUnevictable(page) && (PageActive(page) || lru_gen_enabled())) { int nr_pages =3D thp_nr_pages(page); =20 del_page_from_lru_list(page, lruvec); @@ -666,7 +671,7 @@ void deactivate_file_folio(struct folio *folio) */ void deactivate_page(struct page *page) { - if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) { + if (PageLRU(page) && !PageUnevictable(page) && (PageActive(page) || lru_g= en_enabled())) { struct pagevec *pvec; =20 local_lock(&lru_pvecs.lock); diff --git a/mm/vmscan.c b/mm/vmscan.c index 2232cb55af41..b41ff9765cc7 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2968,6 +2968,81 @@ static bool can_age_anon_pages(struct pglist_data *p= gdat, return can_demote(pgdat->node_id, sc); } =20 +#ifdef CONFIG_LRU_GEN + +/*************************************************************************= ***** + * shorthand helpers + *************************************************************************= *****/ + +#define for_each_gen_type_zone(gen, type, zone) \ + for ((gen) =3D 0; (gen) < MAX_NR_GENS; (gen)++) \ + for ((type) =3D 0; (type) < ANON_AND_FILE; (type)++) \ + for ((zone) =3D 0; (zone) < MAX_NR_ZONES; (zone)++) + +static struct lruvec __maybe_unused *get_lruvec(struct mem_cgroup *memcg, = int nid) +{ + struct pglist_data *pgdat =3D NODE_DATA(nid); + +#ifdef CONFIG_MEMCG + if (memcg) { + struct lruvec *lruvec =3D &memcg->nodeinfo[nid]->lruvec; + + /* for hotadd_new_pgdat() */ + if (!lruvec->pgdat) + lruvec->pgdat =3D pgdat; + + return lruvec; + } +#endif + VM_WARN_ON_ONCE(!mem_cgroup_disabled()); + + return pgdat ? &pgdat->__lruvec : NULL; +} + +/*************************************************************************= ***** + * initialization + *************************************************************************= *****/ + +void lru_gen_init_lruvec(struct lruvec *lruvec) +{ + int gen, type, zone; + struct lru_gen_struct *lrugen =3D &lruvec->lrugen; + + lrugen->max_seq =3D MIN_NR_GENS + 1; + + for_each_gen_type_zone(gen, type, zone) + INIT_LIST_HEAD(&lrugen->lists[gen][type][zone]); +} + +#ifdef CONFIG_MEMCG +void lru_gen_init_memcg(struct mem_cgroup *memcg) +{ +} + +void lru_gen_exit_memcg(struct mem_cgroup *memcg) +{ + int nid; + + for_each_node(nid) { + struct lruvec *lruvec =3D get_lruvec(memcg, nid); + + VM_WARN_ON_ONCE(memchr_inv(lruvec->lrugen.nr_pages, 0, + sizeof(lruvec->lrugen.nr_pages))); + } +} +#endif + +static int __init init_lru_gen(void) +{ + BUILD_BUG_ON(MIN_NR_GENS + 1 >=3D MAX_NR_GENS); + BUILD_BUG_ON(BIT(LRU_GEN_WIDTH) <=3D MAX_NR_GENS); + + return 0; +}; +late_initcall(init_lru_gen); + +#endif /* CONFIG_LRU_GEN */ + static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) { unsigned long nr[NR_LRU_LISTS]; --=20 2.36.0.550.gb090851708-goog