From patchwork Mon Mar 9 17:03:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 213179 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 425ADC10F27 for ; Mon, 9 Mar 2020 17:04:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECE582465D for ; Mon, 9 Mar 2020 17:04:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727225AbgCIREA (ORCPT ); Mon, 9 Mar 2020 13:04:00 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:59739 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727101AbgCIREA (ORCPT ); Mon, 9 Mar 2020 13:04:00 -0400 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1jBLoo-0003W9-CV; Mon, 09 Mar 2020 18:03:54 +0100 Date: Mon, 9 Mar 2020 18:03:54 +0100 From: Sebastian Andrzej Siewior To: linux-rt-users@vger.kernel.org Cc: Steven Rostedt , Thomas Gleixner , Luiz Capitulino Subject: [PATCH RT] mm: Revert the DEFINE_PER_CPU_PAGEVEC implementation Message-ID: <20200309170354.pw5drgdga5flgs36@linutronix.de> MIME-Version: 1.0 Content-Disposition: inline Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org In the v5.4-RT cycle the local-lock based locking for struct pagevec was replaced with explicit per-CPU locking of the struct pagevec. This explicit locking was used if NO_HZ_FULL was active and if was always used on -RT. Upstream wasn't too excited about this so we will probably stick with the local-lock based "fix" to deal with the required locking. This is an all-in-one change containing - a revert of the following patches: 0001-mm-page_alloc-Split-drain_local_pages.patch 0002-mm-swap-Add-static-key-dependent-pagevec-locking.patch 0003-mm-swap-Access-struct-pagevec-remotely.patch 0004-mm-swap-Enable-use_pvec_lock-nohz_full-dependent.patch mm-swap-Enable-use-pvec-lock-on-RT.patch - adding back the old patches: mm-convert-swap-to-percpu-locked.patch mm-perform-lru_add_drain_all-remotely.patch Since the v5.4 series will be maintained for a bit longer I don't want to divert the trees more than they have to and so this brings the old behaviour we had in v5.2-RT and earlier. Signed-off-by: Sebastian Andrzej Siewior --- include/linux/gfp.h | 1 - include/linux/swap.h | 2 + kernel/sched/isolation.c | 14 +- mm/compaction.c | 16 +-- mm/internal.h | 6 - mm/page_alloc.c | 35 ++--- mm/swap.c | 297 ++++++++++++--------------------------- 7 files changed, 113 insertions(+), 258 deletions(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 6ce61770ef343..61f2f6ff94673 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -580,7 +580,6 @@ extern void page_frag_free(void *addr); void page_alloc_init(void); void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp); void drain_all_pages(struct zone *zone); -void drain_cpu_pages(unsigned int cpu, struct zone *zone); void drain_local_pages(struct zone *zone); void page_alloc_init_late(void); diff --git a/include/linux/swap.h b/include/linux/swap.h index 063c0c1e112bd..1ddf6a825468e 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -12,6 +12,7 @@ #include #include #include +#include #include struct notifier_block; @@ -328,6 +329,7 @@ extern unsigned long nr_free_pagecache_pages(void); /* linux/mm/swap.c */ +DECLARE_LOCAL_IRQ_LOCK(swapvec_lock); extern void lru_cache_add(struct page *); extern void lru_cache_add_anon(struct page *page); extern void lru_cache_add_file(struct page *page); diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index a1f9c3f66304c..9fcb2a695a412 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -8,7 +8,6 @@ * */ #include "sched.h" -#include "../../mm/internal.h" DEFINE_STATIC_KEY_FALSE(housekeeping_overridden); EXPORT_SYMBOL_GPL(housekeeping_overridden); @@ -140,21 +139,10 @@ static int __init housekeeping_setup(char *str, enum hk_flags flags) static int __init housekeeping_nohz_full_setup(char *str) { unsigned int flags; - int ret; flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC; - ret = housekeeping_setup(str, flags); - - /* - * Protect struct pagevec with a lock instead using preemption disable; - * with lock protection, remote handling of events instead of queue - * work on remote cpu is default behavior. - */ - if (ret) - static_branch_enable(&use_pvec_lock); - - return ret; + return housekeeping_setup(str, flags); } __setup("nohz_full=", housekeeping_nohz_full_setup); diff --git a/mm/compaction.c b/mm/compaction.c index 03c9e335fa8b0..83cc3d1e5df7b 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -2244,16 +2244,12 @@ compact_zone(struct compact_control *cc, struct capture_control *capc) block_start_pfn(cc->migrate_pfn, cc->order); if (last_migrated_pfn < current_block_start) { - if (static_branch_likely(&use_pvec_lock)) { - cpu = raw_smp_processor_id(); - lru_add_drain_cpu(cpu); - drain_cpu_pages(cpu, cc->zone); - } else { - cpu = get_cpu(); - lru_add_drain_cpu(cpu); - drain_local_pages(cc->zone); - put_cpu(); - } + cpu = get_cpu_light(); + local_lock_irq(swapvec_lock); + lru_add_drain_cpu(cpu); + local_unlock_irq(swapvec_lock); + drain_local_pages(cc->zone); + put_cpu_light(); /* No more flushing until we migrate again */ last_migrated_pfn = 0; } diff --git a/mm/internal.h b/mm/internal.h index 874741f333cf8..7dd7fbb577a9a 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -32,12 +32,6 @@ /* Do not use these with a slab allocator */ #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK) -#ifdef CONFIG_PREEMPT_RT -extern struct static_key_true use_pvec_lock; -#else -extern struct static_key_false use_pvec_lock; -#endif - void page_writeback_init(void); vm_fault_t do_swap_page(struct vm_fault *vmf); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b9bbc72c073e1..99a51dfed59c7 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2883,14 +2883,6 @@ static void drain_pages(unsigned int cpu) } } -void drain_cpu_pages(unsigned int cpu, struct zone *zone) -{ - if (zone) - drain_pages_zone(cpu, zone); - else - drain_pages(cpu); -} - /* * Spill all of this CPU's per-cpu pages back into the buddy allocator. * @@ -2901,7 +2893,10 @@ void drain_local_pages(struct zone *zone) { int cpu = smp_processor_id(); - drain_cpu_pages(cpu, zone); + if (zone) + drain_pages_zone(cpu, zone); + else + drain_pages(cpu); } static void drain_local_pages_wq(struct work_struct *work) @@ -2988,20 +2983,15 @@ void drain_all_pages(struct zone *zone) cpumask_clear_cpu(cpu, &cpus_with_pcps); } - if (static_branch_likely(&use_pvec_lock)) { - for_each_cpu(cpu, &cpus_with_pcps) - drain_cpu_pages(cpu, zone); - } else { - for_each_cpu(cpu, &cpus_with_pcps) { - struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu); + for_each_cpu(cpu, &cpus_with_pcps) { + struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu); - drain->zone = zone; - INIT_WORK(&drain->work, drain_local_pages_wq); - queue_work_on(cpu, mm_percpu_wq, &drain->work); - } - for_each_cpu(cpu, &cpus_with_pcps) - flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work); + drain->zone = zone; + INIT_WORK(&drain->work, drain_local_pages_wq); + queue_work_on(cpu, mm_percpu_wq, &drain->work); } + for_each_cpu(cpu, &cpus_with_pcps) + flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work); mutex_unlock(&pcpu_drain_mutex); } @@ -7686,8 +7676,9 @@ void __init free_area_init(unsigned long *zones_size) static int page_alloc_cpu_dead(unsigned int cpu) { - + local_lock_irq_on(swapvec_lock, cpu); lru_add_drain_cpu(cpu); + local_unlock_irq_on(swapvec_lock, cpu); drain_pages(cpu); /* diff --git a/mm/swap.c b/mm/swap.c index 98accaf51fce8..cdb4f1fa3a483 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -44,111 +45,16 @@ /* How many pages do we try to swap or page in/out together? */ int page_cluster; -#ifdef CONFIG_PREEMPT_RT -DEFINE_STATIC_KEY_TRUE(use_pvec_lock); -#else -DEFINE_STATIC_KEY_FALSE(use_pvec_lock); -#endif - -struct swap_pagevec { - spinlock_t lock; - struct pagevec pvec; -}; - -#define DEFINE_PER_CPU_PAGEVEC(lvar) \ - DEFINE_PER_CPU(struct swap_pagevec, lvar) = { \ - .lock = __SPIN_LOCK_UNLOCKED((lvar).lock) } - -static DEFINE_PER_CPU_PAGEVEC(lru_add_pvec); -static DEFINE_PER_CPU_PAGEVEC(lru_rotate_pvecs); -static DEFINE_PER_CPU_PAGEVEC(lru_deactivate_file_pvecs); -static DEFINE_PER_CPU_PAGEVEC(lru_deactivate_pvecs); -static DEFINE_PER_CPU_PAGEVEC(lru_lazyfree_pvecs); +static DEFINE_PER_CPU(struct pagevec, lru_add_pvec); +static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); +static DEFINE_PER_CPU(struct pagevec, lru_deactivate_file_pvecs); +static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs); +static DEFINE_PER_CPU(struct pagevec, lru_lazyfree_pvecs); #ifdef CONFIG_SMP -static DEFINE_PER_CPU_PAGEVEC(activate_page_pvecs); +static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs); #endif - -static inline -struct swap_pagevec *lock_swap_pvec(struct swap_pagevec __percpu *p) -{ - struct swap_pagevec *swpvec; - - if (static_branch_likely(&use_pvec_lock)) { - swpvec = raw_cpu_ptr(p); - - spin_lock(&swpvec->lock); - } else { - swpvec = &get_cpu_var(*p); - } - return swpvec; -} - -static inline struct swap_pagevec * -lock_swap_pvec_cpu(struct swap_pagevec __percpu *p, int cpu) -{ - struct swap_pagevec *swpvec = per_cpu_ptr(p, cpu); - - if (static_branch_likely(&use_pvec_lock)) - spin_lock(&swpvec->lock); - - return swpvec; -} - -static inline struct swap_pagevec * -lock_swap_pvec_irqsave(struct swap_pagevec __percpu *p, unsigned long *flags) -{ - struct swap_pagevec *swpvec; - - if (static_branch_likely(&use_pvec_lock)) { - swpvec = raw_cpu_ptr(p); - - spin_lock_irqsave(&swpvec->lock, (*flags)); - } else { - local_irq_save(*flags); - - swpvec = this_cpu_ptr(p); - } - return swpvec; -} - -static inline struct swap_pagevec * -lock_swap_pvec_cpu_irqsave(struct swap_pagevec __percpu *p, int cpu, - unsigned long *flags) -{ - struct swap_pagevec *swpvec = per_cpu_ptr(p, cpu); - - if (static_branch_likely(&use_pvec_lock)) - spin_lock_irqsave(&swpvec->lock, *flags); - else - local_irq_save(*flags); - - return swpvec; -} - -static inline void unlock_swap_pvec(struct swap_pagevec *swpvec, - struct swap_pagevec __percpu *p) -{ - if (static_branch_likely(&use_pvec_lock)) - spin_unlock(&swpvec->lock); - else - put_cpu_var(*p); - -} - -static inline void unlock_swap_pvec_cpu(struct swap_pagevec *swpvec) -{ - if (static_branch_likely(&use_pvec_lock)) - spin_unlock(&swpvec->lock); -} - -static inline void -unlock_swap_pvec_irqrestore(struct swap_pagevec *swpvec, unsigned long flags) -{ - if (static_branch_likely(&use_pvec_lock)) - spin_unlock_irqrestore(&swpvec->lock, flags); - else - local_irq_restore(flags); -} +static DEFINE_LOCAL_IRQ_LOCK(rotate_lock); +DEFINE_LOCAL_IRQ_LOCK(swapvec_lock); /* * This path almost never happens for VM activity - pages are normally @@ -347,17 +253,15 @@ void rotate_reclaimable_page(struct page *page) { if (!PageLocked(page) && !PageDirty(page) && !PageUnevictable(page) && PageLRU(page)) { - struct swap_pagevec *swpvec; struct pagevec *pvec; unsigned long flags; get_page(page); - - swpvec = lock_swap_pvec_irqsave(&lru_rotate_pvecs, &flags); - pvec = &swpvec->pvec; + local_lock_irqsave(rotate_lock, flags); + pvec = this_cpu_ptr(&lru_rotate_pvecs); if (!pagevec_add(pvec, page) || PageCompound(page)) pagevec_move_tail(pvec); - unlock_swap_pvec_irqrestore(swpvec, flags); + local_unlock_irqrestore(rotate_lock, flags); } } @@ -392,32 +296,28 @@ static void __activate_page(struct page *page, struct lruvec *lruvec, #ifdef CONFIG_SMP static void activate_page_drain(int cpu) { - struct swap_pagevec *swpvec = lock_swap_pvec_cpu(&activate_page_pvecs, cpu); - struct pagevec *pvec = &swpvec->pvec; + struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu); if (pagevec_count(pvec)) pagevec_lru_move_fn(pvec, __activate_page, NULL); - unlock_swap_pvec_cpu(swpvec); } static bool need_activate_page_drain(int cpu) { - return pagevec_count(per_cpu_ptr(&activate_page_pvecs.pvec, cpu)) != 0; + return pagevec_count(&per_cpu(activate_page_pvecs, cpu)) != 0; } void activate_page(struct page *page) { page = compound_head(page); if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { - struct swap_pagevec *swpvec; - struct pagevec *pvec; + struct pagevec *pvec = &get_locked_var(swapvec_lock, + activate_page_pvecs); get_page(page); - swpvec = lock_swap_pvec(&activate_page_pvecs); - pvec = &swpvec->pvec; if (!pagevec_add(pvec, page) || PageCompound(page)) pagevec_lru_move_fn(pvec, __activate_page, NULL); - unlock_swap_pvec(swpvec, &activate_page_pvecs); + put_locked_var(swapvec_lock, activate_page_pvecs); } } @@ -439,8 +339,7 @@ void activate_page(struct page *page) static void __lru_cache_activate_page(struct page *page) { - struct swap_pagevec *swpvec = lock_swap_pvec(&lru_add_pvec); - struct pagevec *pvec = &swpvec->pvec; + struct pagevec *pvec = &get_locked_var(swapvec_lock, lru_add_pvec); int i; /* @@ -462,7 +361,7 @@ static void __lru_cache_activate_page(struct page *page) } } - unlock_swap_pvec(swpvec, &lru_add_pvec); + put_locked_var(swapvec_lock, lru_add_pvec); } /* @@ -504,13 +403,12 @@ EXPORT_SYMBOL(mark_page_accessed); static void __lru_cache_add(struct page *page) { - struct swap_pagevec *swpvec = lock_swap_pvec(&lru_add_pvec); - struct pagevec *pvec = &swpvec->pvec; + struct pagevec *pvec = &get_locked_var(swapvec_lock, lru_add_pvec); get_page(page); if (!pagevec_add(pvec, page) || PageCompound(page)) __pagevec_lru_add(pvec); - unlock_swap_pvec(swpvec, &lru_add_pvec); + put_locked_var(swapvec_lock, lru_add_pvec); } /** @@ -694,40 +592,38 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec, */ void lru_add_drain_cpu(int cpu) { - struct swap_pagevec *swpvec = lock_swap_pvec_cpu(&lru_add_pvec, cpu); - struct pagevec *pvec = &swpvec->pvec; - unsigned long flags; + struct pagevec *pvec = &per_cpu(lru_add_pvec, cpu); if (pagevec_count(pvec)) __pagevec_lru_add(pvec); - unlock_swap_pvec_cpu(swpvec); - swpvec = lock_swap_pvec_cpu_irqsave(&lru_rotate_pvecs, cpu, &flags); - pvec = &swpvec->pvec; + pvec = &per_cpu(lru_rotate_pvecs, cpu); if (pagevec_count(pvec)) { + unsigned long flags; /* No harm done if a racing interrupt already did this */ +#ifdef CONFIG_PREEMPT_RT + local_lock_irqsave_on(rotate_lock, flags, cpu); pagevec_move_tail(pvec); + local_unlock_irqrestore_on(rotate_lock, flags, cpu); +#else + local_lock_irqsave(rotate_lock, flags); + pagevec_move_tail(pvec); + local_unlock_irqrestore(rotate_lock, flags); +#endif } - unlock_swap_pvec_irqrestore(swpvec, flags); - swpvec = lock_swap_pvec_cpu(&lru_deactivate_file_pvecs, cpu); - pvec = &swpvec->pvec; + pvec = &per_cpu(lru_deactivate_file_pvecs, cpu); if (pagevec_count(pvec)) pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL); - unlock_swap_pvec_cpu(swpvec); - swpvec = lock_swap_pvec_cpu(&lru_deactivate_pvecs, cpu); - pvec = &swpvec->pvec; + pvec = &per_cpu(lru_deactivate_pvecs, cpu); if (pagevec_count(pvec)) pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); - unlock_swap_pvec_cpu(swpvec); - swpvec = lock_swap_pvec_cpu(&lru_lazyfree_pvecs, cpu); - pvec = &swpvec->pvec; + pvec = &per_cpu(lru_lazyfree_pvecs, cpu); if (pagevec_count(pvec)) pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL); - unlock_swap_pvec_cpu(swpvec); activate_page_drain(cpu); } @@ -742,9 +638,6 @@ void lru_add_drain_cpu(int cpu) */ void deactivate_file_page(struct page *page) { - struct swap_pagevec *swpvec; - struct pagevec *pvec; - /* * In a workload with many unevictable page such as mprotect, * unevictable page deactivation for accelerating reclaim is pointless. @@ -753,12 +646,12 @@ void deactivate_file_page(struct page *page) return; if (likely(get_page_unless_zero(page))) { - swpvec = lock_swap_pvec(&lru_deactivate_file_pvecs); - pvec = &swpvec->pvec; + struct pagevec *pvec = &get_locked_var(swapvec_lock, + lru_deactivate_file_pvecs); if (!pagevec_add(pvec, page) || PageCompound(page)) pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL); - unlock_swap_pvec(swpvec, &lru_deactivate_file_pvecs); + put_locked_var(swapvec_lock, lru_deactivate_file_pvecs); } } @@ -773,16 +666,12 @@ void deactivate_file_page(struct page *page) void deactivate_page(struct page *page) { if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) { - struct swap_pagevec *swpvec; - struct pagevec *pvec; - - swpvec = lock_swap_pvec(&lru_deactivate_pvecs); - pvec = &swpvec->pvec; + struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs); get_page(page); if (!pagevec_add(pvec, page) || PageCompound(page)) pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); - unlock_swap_pvec(swpvec, &lru_deactivate_pvecs); + put_cpu_var(lru_deactivate_pvecs); } } @@ -795,33 +684,36 @@ void deactivate_page(struct page *page) */ void mark_page_lazyfree(struct page *page) { - struct swap_pagevec *swpvec; - struct pagevec *pvec; - if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page) && !PageUnevictable(page)) { - swpvec = lock_swap_pvec(&lru_lazyfree_pvecs); - pvec = &swpvec->pvec; + struct pagevec *pvec = &get_locked_var(swapvec_lock, + lru_lazyfree_pvecs); get_page(page); if (!pagevec_add(pvec, page) || PageCompound(page)) pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL); - unlock_swap_pvec(swpvec, &lru_lazyfree_pvecs); + put_locked_var(swapvec_lock, lru_lazyfree_pvecs); } } void lru_add_drain(void) { - if (static_branch_likely(&use_pvec_lock)) { - lru_add_drain_cpu(raw_smp_processor_id()); - } else { - lru_add_drain_cpu(get_cpu()); - put_cpu(); - } + lru_add_drain_cpu(local_lock_cpu(swapvec_lock)); + local_unlock_cpu(swapvec_lock); } #ifdef CONFIG_SMP +#ifdef CONFIG_PREEMPT_RT +static inline void remote_lru_add_drain(int cpu, struct cpumask *has_work) +{ + local_lock_on(swapvec_lock, cpu); + lru_add_drain_cpu(cpu); + local_unlock_on(swapvec_lock, cpu); +} + +#else + static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work); static void lru_add_drain_per_cpu(struct work_struct *dummy) @@ -829,6 +721,16 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy) lru_add_drain(); } +static inline void remote_lru_add_drain(int cpu, struct cpumask *has_work) +{ + struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); + + INIT_WORK(work, lru_add_drain_per_cpu); + queue_work_on(cpu, mm_percpu_wq, work); + cpumask_set_cpu(cpu, has_work); +} +#endif + /* * Doesn't need any cpu hotplug locking because we do rely on per-cpu * kworkers being shut down before our page_alloc_cpu_dead callback is @@ -838,54 +740,37 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy) */ void lru_add_drain_all(void) { - if (static_branch_likely(&use_pvec_lock)) { - int cpu; + static DEFINE_MUTEX(lock); + static struct cpumask has_work; + int cpu; - for_each_online_cpu(cpu) { - if (pagevec_count(&per_cpu(lru_add_pvec.pvec, cpu)) || - pagevec_count(&per_cpu(lru_rotate_pvecs.pvec, cpu)) || - pagevec_count(&per_cpu(lru_deactivate_file_pvecs.pvec, cpu)) || - pagevec_count(&per_cpu(lru_deactivate_pvecs.pvec, cpu)) || - pagevec_count(&per_cpu(lru_lazyfree_pvecs.pvec, cpu)) || - need_activate_page_drain(cpu)) { - lru_add_drain_cpu(cpu); - } - } - } else { - static DEFINE_MUTEX(lock); - static struct cpumask has_work; - int cpu; + /* + * Make sure nobody triggers this path before mm_percpu_wq is fully + * initialized. + */ + if (WARN_ON(!mm_percpu_wq)) + return; - /* - * Make sure nobody triggers this path before mm_percpu_wq - * is fully initialized. - */ - if (WARN_ON(!mm_percpu_wq)) - return; + mutex_lock(&lock); + cpumask_clear(&has_work); - mutex_lock(&lock); - cpumask_clear(&has_work); + for_each_online_cpu(cpu) { - for_each_online_cpu(cpu) { - struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); - - if (pagevec_count(&per_cpu(lru_add_pvec.pvec, cpu)) || - pagevec_count(&per_cpu(lru_rotate_pvecs.pvec, cpu)) || - pagevec_count(&per_cpu(lru_deactivate_file_pvecs.pvec, cpu)) || - pagevec_count(&per_cpu(lru_deactivate_pvecs.pvec, cpu)) || - pagevec_count(&per_cpu(lru_lazyfree_pvecs.pvec, cpu)) || - need_activate_page_drain(cpu)) { - INIT_WORK(work, lru_add_drain_per_cpu); - queue_work_on(cpu, mm_percpu_wq, work); - cpumask_set_cpu(cpu, &has_work); - } - } - - for_each_cpu(cpu, &has_work) - flush_work(&per_cpu(lru_add_drain_work, cpu)); - - mutex_unlock(&lock); + if (pagevec_count(&per_cpu(lru_add_pvec, cpu)) || + pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) || + pagevec_count(&per_cpu(lru_deactivate_file_pvecs, cpu)) || + pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) || + pagevec_count(&per_cpu(lru_lazyfree_pvecs, cpu)) || + need_activate_page_drain(cpu)) + remote_lru_add_drain(cpu, &has_work); } + +#ifndef CONFIG_PREEMPT_RT + for_each_cpu(cpu, &has_work) + flush_work(&per_cpu(lru_add_drain_work, cpu)); +#endif + + mutex_unlock(&lock); } #else void lru_add_drain_all(void)