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Howlett" To: maple-tree@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Andrew Morton , Song Liu , Davidlohr Bueso , "Paul E . McKenney" , Matthew Wilcox , Jerome Glisse , David Rientjes , Axel Rasmussen , Suren Baghdasaryan , Vlastimil Babka Subject: [PATCH 19/28] mm: Remove vmacache Date: Thu, 10 Dec 2020 12:03:53 -0500 Message-Id: <20201210170402.3468568-20-Liam.Howlett@Oracle.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201210170402.3468568-1-Liam.Howlett@Oracle.com> References: <20201210170402.3468568-1-Liam.Howlett@Oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9830 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 suspectscore=0 bulkscore=0 malwarescore=0 phishscore=0 mlxscore=0 spamscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012100106 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9830 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxlogscore=999 clxscore=1015 malwarescore=0 priorityscore=1501 adultscore=0 lowpriorityscore=0 phishscore=0 spamscore=0 impostorscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012100106 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The maple tree is able to find a VMA quick enough to no longer need the vma cache. Remove the vmacache to reduce work in keeping it up to date and code complexity. Signed-off-by: Liam R. Howlett --- fs/exec.c | 3 - fs/proc/task_mmu.c | 1 - include/linux/mm_types.h | 1 - include/linux/mm_types_task.h | 5 -- include/linux/sched.h | 1 - include/linux/vmacache.h | 28 -------- kernel/debug/debug_core.c | 12 ---- kernel/fork.c | 5 -- mm/Makefile | 2 +- mm/debug.c | 4 +- mm/mmap.c | 20 ------ mm/vmacache.c | 117 ---------------------------------- 12 files changed, 3 insertions(+), 196 deletions(-) delete mode 100644 include/linux/vmacache.h delete mode 100644 mm/vmacache.c diff --git a/fs/exec.c b/fs/exec.c index 547a2390baf54..aa466921d6a97 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -28,7 +28,6 @@ #include #include #include -#include #include #include #include @@ -1019,8 +1018,6 @@ static int exec_mmap(struct mm_struct *mm) activate_mm(active_mm, mm); if (IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM)) local_irq_enable(); - tsk->mm->vmacache_seqnum = 0; - vmacache_flush(tsk); task_unlock(tsk); if (old_mm) { mmap_read_unlock(old_mm); diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 217aa2705d5df..5161d8ea2d729 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1,6 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 #include -#include #include #include #include diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index fa3cf29f01f21..5a85b76bb9b9a 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -380,7 +380,6 @@ struct mm_struct { struct { struct vm_area_struct *mmap; /* list of VMAs */ struct maple_tree mm_mt; - u64 vmacache_seqnum; /* per-thread vmacache */ #ifdef CONFIG_MMU unsigned long (*get_unmapped_area) (struct file *filp, unsigned long addr, unsigned long len, diff --git a/include/linux/mm_types_task.h b/include/linux/mm_types_task.h index c1bc6731125cb..33c9fa4d4f66a 100644 --- a/include/linux/mm_types_task.h +++ b/include/linux/mm_types_task.h @@ -31,11 +31,6 @@ #define VMACACHE_SIZE (1U << VMACACHE_BITS) #define VMACACHE_MASK (VMACACHE_SIZE - 1) -struct vmacache { - u64 seqnum; - struct vm_area_struct *vmas[VMACACHE_SIZE]; -}; - /* * When updating this, please also update struct resident_page_types[] in * kernel/fork.c diff --git a/include/linux/sched.h b/include/linux/sched.h index 063cd120b4593..6e4cb78e5d1ab 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -750,7 +750,6 @@ struct task_struct { struct mm_struct *active_mm; /* Per-thread vma caching: */ - struct vmacache vmacache; #ifdef SPLIT_RSS_COUNTING struct task_rss_stat rss_stat; diff --git a/include/linux/vmacache.h b/include/linux/vmacache.h deleted file mode 100644 index 6fce268a4588e..0000000000000 --- a/include/linux/vmacache.h +++ /dev/null @@ -1,28 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef __LINUX_VMACACHE_H -#define __LINUX_VMACACHE_H - -#include -#include - -static inline void vmacache_flush(struct task_struct *tsk) -{ - memset(tsk->vmacache.vmas, 0, sizeof(tsk->vmacache.vmas)); -} - -extern void vmacache_update(unsigned long addr, struct vm_area_struct *newvma); -extern struct vm_area_struct *vmacache_find(struct mm_struct *mm, - unsigned long addr); - -#ifndef CONFIG_MMU -extern struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm, - unsigned long start, - unsigned long end); -#endif - -static inline void vmacache_invalidate(struct mm_struct *mm) -{ - mm->vmacache_seqnum++; -} - -#endif /* __LINUX_VMACACHE_H */ diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 1e75a8923a8d1..f6e7156088ea7 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -53,7 +53,6 @@ #include #include #include -#include #include #include @@ -286,17 +285,6 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) if (!CACHE_FLUSH_IS_SAFE) return; - if (current->mm) { - int i; - - for (i = 0; i < VMACACHE_SIZE; i++) { - if (!current->vmacache.vmas[i]) - continue; - flush_cache_range(current->vmacache.vmas[i], - addr, addr + BREAK_INSTR_SIZE); - } - } - /* Force flush instruction cache if it was outside the mm */ flush_icache_range(addr, addr + BREAK_INSTR_SIZE); } diff --git a/kernel/fork.c b/kernel/fork.c index 5e4de4b860439..52ff974dac511 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -42,7 +42,6 @@ #include #include #include -#include #include #include #include @@ -1011,7 +1010,6 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, { mm->mmap = NULL; mt_init_flags(&mm->mm_mt, MAPLE_ALLOC_RANGE); - mm->vmacache_seqnum = 0; atomic_set(&mm->mm_users, 1); atomic_set(&mm->mm_count, 1); mmap_init_lock(mm); @@ -1408,9 +1406,6 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) if (!oldmm) return 0; - /* initialize the new vmacache entries */ - vmacache_flush(tsk); - if (clone_flags & CLONE_VM) { mmget(oldmm); mm = oldmm; diff --git a/mm/Makefile b/mm/Makefile index d73aed0fc99c1..ca05b84ac738b 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -50,7 +50,7 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ readahead.o swap.o truncate.o vmscan.o shmem.o \ util.o mmzone.o vmstat.o backing-dev.o \ mm_init.o percpu.o slab_common.o \ - compaction.o vmacache.o \ + compaction.o \ interval_tree.o list_lru.o workingset.o \ debug.o gup.o $(mmu-y) diff --git a/mm/debug.c b/mm/debug.c index ccca576b28990..d8ed9d7383267 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -214,7 +214,7 @@ EXPORT_SYMBOL(dump_vma); void dump_mm(const struct mm_struct *mm) { - pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n" + pr_emerg("mm %px mmap %px task_size %lu\n" #ifdef CONFIG_MMU "get_unmapped_area %px\n" #endif @@ -242,7 +242,7 @@ void dump_mm(const struct mm_struct *mm) "tlb_flush_pending %d\n" "def_flags: %#lx(%pGv)\n", - mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size, + mm, mm->mmap, mm->task_size, #ifdef CONFIG_MMU mm->get_unmapped_area, #endif diff --git a/mm/mmap.c b/mm/mmap.c index d7a7d01f696c1..c3ac4d6f970d3 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -13,7 +13,6 @@ #include #include #include -#include #include #include #include @@ -693,9 +692,6 @@ inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma, /* Remove from mm linked list - also updates highest_vm_end */ __vma_unlink_list(mm, next); - /* Kill the cache */ - vmacache_invalidate(mm); - if (file) __remove_shared_vm_struct(next, file, mapping); @@ -909,8 +905,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start, if (remove_next) { __vma_unlink_list(mm, next); - /* Kill the cache */ - vmacache_invalidate(mm); if (file) __remove_shared_vm_struct(next, file, mapping); } else if (insert) { @@ -2197,19 +2191,9 @@ struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, { struct vm_area_struct *vma; MA_STATE(mas, &mm->mm_mt, start_addr, start_addr); - - /* Check the cache first. */ - vma = vmacache_find(mm, start_addr); - if (likely(vma)) - return vma; - rcu_read_lock(); vma = mas_find(&mas, end_addr - 1); rcu_read_unlock(); - - if (vma) - vmacache_update(start_addr, vma); - return vma; } EXPORT_SYMBOL(find_vma_intersection); @@ -2604,9 +2588,6 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, mm->highest_vm_end = prev ? vm_end_gap(prev) : 0; tail_vma->vm_next = NULL; - /* Kill the cache */ - vmacache_invalidate(mm); - /* * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or * VM_GROWSUP VMA. Such VMAs can change their size under @@ -3003,7 +2984,6 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma, if (vma_mas_remove(&unmap, mas)) goto mas_store_fail; - vmacache_invalidate(vma->vm_mm); if (vma->anon_vma) { anon_vma_interval_tree_post_update_vma(vma); anon_vma_unlock_write(vma->anon_vma); diff --git a/mm/vmacache.c b/mm/vmacache.c deleted file mode 100644 index 01a6e6688ec1f..0000000000000 --- a/mm/vmacache.c +++ /dev/null @@ -1,117 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Copyright (C) 2014 Davidlohr Bueso. - */ -#include -#include -#include -#include - -/* - * Hash based on the pmd of addr if configured with MMU, which provides a good - * hit rate for workloads with spatial locality. Otherwise, use pages. - */ -#ifdef CONFIG_MMU -#define VMACACHE_SHIFT PMD_SHIFT -#else -#define VMACACHE_SHIFT PAGE_SHIFT -#endif -#define VMACACHE_HASH(addr) ((addr >> VMACACHE_SHIFT) & VMACACHE_MASK) - -/* - * This task may be accessing a foreign mm via (for example) - * get_user_pages()->find_vma(). The vmacache is task-local and this - * task's vmacache pertains to a different mm (ie, its own). There is - * nothing we can do here. - * - * Also handle the case where a kernel thread has adopted this mm via - * kthread_use_mm(). That kernel thread's vmacache is not applicable to this mm. - */ -static inline bool vmacache_valid_mm(struct mm_struct *mm) -{ - return current->mm == mm && !(current->flags & PF_KTHREAD); -} - -void vmacache_update(unsigned long addr, struct vm_area_struct *newvma) -{ - if (vmacache_valid_mm(newvma->vm_mm)) - current->vmacache.vmas[VMACACHE_HASH(addr)] = newvma; -} - -static bool vmacache_valid(struct mm_struct *mm) -{ - struct task_struct *curr; - - if (!vmacache_valid_mm(mm)) - return false; - - curr = current; - if (mm->vmacache_seqnum != curr->vmacache.seqnum) { - /* - * First attempt will always be invalid, initialize - * the new cache for this task here. - */ - curr->vmacache.seqnum = mm->vmacache_seqnum; - vmacache_flush(curr); - return false; - } - return true; -} - -struct vm_area_struct *vmacache_find(struct mm_struct *mm, unsigned long addr) -{ - int idx = VMACACHE_HASH(addr); - int i; - - count_vm_vmacache_event(VMACACHE_FIND_CALLS); - - if (!vmacache_valid(mm)) - return NULL; - - for (i = 0; i < VMACACHE_SIZE; i++) { - struct vm_area_struct *vma = current->vmacache.vmas[idx]; - - if (vma) { -#ifdef CONFIG_DEBUG_VM_VMACACHE - if (WARN_ON_ONCE(vma->vm_mm != mm)) - break; -#endif - if (vma->vm_start <= addr && vma->vm_end > addr) { - count_vm_vmacache_event(VMACACHE_FIND_HITS); - return vma; - } - } - if (++idx == VMACACHE_SIZE) - idx = 0; - } - - return NULL; -} - -#ifndef CONFIG_MMU -struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm, - unsigned long start, - unsigned long end) -{ - int idx = VMACACHE_HASH(start); - int i; - - count_vm_vmacache_event(VMACACHE_FIND_CALLS); - - if (!vmacache_valid(mm)) - return NULL; - - for (i = 0; i < VMACACHE_SIZE; i++) { - struct vm_area_struct *vma = current->vmacache.vmas[idx]; - - if (vma && vma->vm_start == start && vma->vm_end == end) { - count_vm_vmacache_event(VMACACHE_FIND_HITS); - return vma; - } - if (++idx == VMACACHE_SIZE) - idx = 0; - } - - return NULL; -} -#endif