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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 , Rik van Riel , Peter Zijlstra Subject: [PATCH v2 17/70] mm/mmap: Change mmap_region to use maple tree state Date: Tue, 12 Jan 2021 11:11:47 -0500 Message-Id: <20210112161240.2024684-18-Liam.Howlett@Oracle.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20210112161240.2024684-1-Liam.Howlett@Oracle.com> References: <20210112161240.2024684-1-Liam.Howlett@Oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9862 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 phishscore=0 spamscore=0 malwarescore=0 suspectscore=0 mlxlogscore=999 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101120092 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9862 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 suspectscore=0 clxscore=1015 impostorscore=0 spamscore=0 priorityscore=1501 mlxscore=0 phishscore=0 mlxlogscore=999 bulkscore=0 adultscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101120092 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: Signed-off-by: Liam R. Howlett --- lib/maple_tree.c | 1 + mm/mmap.c | 227 ++++++++++++++++++++++++++++++++++++++++------- 2 files changed, 195 insertions(+), 33 deletions(-) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index c24c6f154c857..522f5fdfe5078 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -3566,6 +3566,7 @@ static inline void *_mas_store(struct ma_state *mas, void *entry, bool overwrite if (ret > 2) return NULL; spanning_store: + return content; } diff --git a/mm/mmap.c b/mm/mmap.c index 6be58594afb3d..d3dfea031c0d5 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -500,9 +500,10 @@ munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len, struct vm_area_struct **pprev, struct list_head *uf) { // Needs optimization. - while (range_has_overlap(mm, start, start + len, pprev)) + while (range_has_overlap(mm, start, start + len, pprev)) { if (do_munmap(mm, start, len, uf)) return -ENOMEM; + } return 0; } static unsigned long count_vma_pages_range(struct mm_struct *mm, @@ -613,6 +614,27 @@ static inline void vma_mt_store(struct mm_struct *mm, struct vm_area_struct *vma } +static void vma_mas_link(struct mm_struct *mm, struct vm_area_struct *vma, + struct ma_state *mas, struct vm_area_struct *prev) +{ + struct address_space *mapping = NULL; + + if (vma->vm_file) { + mapping = vma->vm_file->f_mapping; + i_mmap_lock_write(mapping); + } + + vma_mas_store(vma, mas); + __vma_link_list(mm, vma, prev); + __vma_link_file(vma); + + if (mapping) + i_mmap_unlock_write(mapping); + + mm->map_count++; + validate_mm(mm); +} + static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev) { @@ -649,6 +671,98 @@ static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) mm->map_count++; } +inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma, + unsigned long start, unsigned long end, pgoff_t pgoff, + struct vm_area_struct *next) +{ + struct mm_struct *mm = vma->vm_mm; + struct address_space *mapping = NULL; + struct rb_root_cached *root = NULL; + struct anon_vma *anon_vma = vma->anon_vma; + struct file *file = vma->vm_file; + bool remove_next = false; + int error; + + if (next && (vma != next) && (end == next->vm_end)) { + remove_next = true; + if (next->anon_vma && !vma->anon_vma) { + vma->anon_vma = next->anon_vma; + error = anon_vma_clone(vma, next); + if (error) + return error; + } + } + + vma_adjust_trans_huge(vma, start, end, 0); + + if (file) { + mapping = file->f_mapping; + root = &mapping->i_mmap; + uprobe_munmap(vma, vma->vm_start, vma->vm_end); + i_mmap_lock_write(mapping); + } + + if (anon_vma) { + anon_vma_lock_write(anon_vma); + anon_vma_interval_tree_pre_update_vma(vma); + } + + if (file) { + flush_dcache_mmap_lock(mapping); + vma_interval_tree_remove(vma, root); + } + + vma->vm_start = start; + vma->vm_end = end; + vma->vm_pgoff = pgoff; + /* Note: mas must be pointing to the expanding VMA */ + vma_mas_store(vma, mas); + + if (file) { + vma_interval_tree_insert(vma, root); + flush_dcache_mmap_unlock(mapping); + } + + /* Expanding over the next vma */ + if (remove_next) { + /* 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); + + } else if (!next) { + mm->highest_vm_end = vm_end_gap(vma); + } + + if (anon_vma) { + anon_vma_interval_tree_post_update_vma(vma); + anon_vma_unlock_write(anon_vma); + } + + if (file) { + i_mmap_unlock_write(mapping); + uprobe_mmap(vma); + } + + if (remove_next) { + if (file) { + uprobe_munmap(next, next->vm_start, next->vm_end); + fput(file); + } + if (next->anon_vma) + anon_vma_merge(vma, next); + mm->map_count--; + mpol_put(vma_policy(next)); + vm_area_free(next); + } + + validate_mm(mm); + return 0; +} /* * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that * is already present in an i_mmap tree without adjusting the tree. @@ -1635,9 +1749,15 @@ unsigned long mmap_region(struct file *file, unsigned long addr, struct list_head *uf) { struct mm_struct *mm = current->mm; - struct vm_area_struct *vma, *prev, *merge; - int error; + struct vm_area_struct *vma = NULL; + struct vm_area_struct *prev, *next; + pgoff_t pglen = len >> PAGE_SHIFT; unsigned long charged = 0; + unsigned long end = addr + len; + unsigned long merge_start = addr, merge_end = end; + pgoff_t vm_pgoff; + int error; + MA_STATE(mas, &mm->mm_mt, addr, end - 1); /* Check against address space limit. */ if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { @@ -1647,16 +1767,17 @@ unsigned long mmap_region(struct file *file, unsigned long addr, * MAP_FIXED may remove pages of mappings that intersects with * requested mapping. Account for the pages it would unmap. */ - nr_pages = count_vma_pages_range(mm, addr, addr + len); + nr_pages = count_vma_pages_range(mm, addr, end); if (!may_expand_vm(mm, vm_flags, (len >> PAGE_SHIFT) - nr_pages)) return -ENOMEM; } - /* Clear old maps, set up prev and uf */ - if (munmap_vma_range(mm, addr, len, &prev, uf)) + /* Unmap any existing mapping in the area */ + if (do_munmap(mm, addr, len, uf)) return -ENOMEM; + /* * Private writable mapping: check memory availability */ @@ -1667,14 +1788,46 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vm_flags |= VM_ACCOUNT; } - /* - * Can we just expand an old mapping? - */ - vma = vma_merge(mm, prev, addr, addr + len, vm_flags, - NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX); - if (vma) - goto out; + if (vm_flags & VM_SPECIAL) { + prev = mas_prev(&mas, 0); + goto cannot_expand; + } + + /* Attempt to expand an old mapping */ + + /* Check next */ + next = mas_next(&mas, ULONG_MAX); + if (next && next->vm_start == end && vma_policy(next) && + can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen, + NULL_VM_UFFD_CTX)) { + merge_end = next->vm_end; + vma = next; + vm_pgoff = next->vm_pgoff - pglen; + } + + /* Check prev */ + prev = mas_prev(&mas, 0); + if (prev && prev->vm_end == addr && !vma_policy(prev) && + can_vma_merge_after(prev, vm_flags, NULL, file, pgoff, + NULL_VM_UFFD_CTX)) { + merge_start = prev->vm_start; + vma = prev; + vm_pgoff = prev->vm_pgoff; + } + + + /* Actually expand, if possible */ + if (vma && + !vma_expand(&mas, vma, merge_start, merge_end, vm_pgoff, next)) { + khugepaged_enter_vma_merge(prev, vm_flags); + goto expanded; + } + + mas_reset(&mas); + mas_set(&mas, addr); + mas.last = end - 1; +cannot_expand: /* * Determine the object being mapped and call the appropriate * specific mapper. the address has already been validated, but @@ -1687,7 +1840,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, } vma->vm_start = addr; - vma->vm_end = addr + len; + vma->vm_end = end; vma->vm_flags = vm_flags; vma->vm_page_prot = vm_get_page_prot(vm_flags); vma->vm_pgoff = pgoff; @@ -1728,18 +1881,25 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* If vm_flags changed after call_mmap(), we should try merge vma again * as we may succeed this time. */ - if (unlikely(vm_flags != vma->vm_flags && prev)) { - merge = vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_flags, - NULL, vma->vm_file, vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX); - if (merge) { + if (unlikely(vm_flags != vma->vm_flags && prev && + prev->vm_end == addr && !vma_policy(prev) && + can_vma_merge_after(prev, vm_flags, NULL, file, + pgoff, NULL_VM_UFFD_CTX))) { + merge_start = prev->vm_start; + vm_pgoff = prev->vm_pgoff; + if (!vma_expand(&mas, prev, merge_start, merge_end, + vm_pgoff, next)) { /* ->mmap() can change vma->vm_file and fput the original file. So * fput the vma->vm_file here or we would add an extra fput for file * and cause general protection fault ultimately. */ fput(vma->vm_file); vm_area_free(vma); - vma = merge; - /* Update vm_flags to pick up the change. */ + vma = prev; + /* Update vm_flags and possible addr to pick up the change. We don't + * warn here if addr changed as the vma is not linked by vma_link(). + */ + addr = vma->vm_start; vm_flags = vma->vm_flags; goto unmap_writable; } @@ -1749,7 +1909,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, * * Answer: Yes, several device drivers can do it in their * f_op->mmap method. -DaveM - * Bug: If addr is changed, prev and the maple tree data should + * Bug: If addr is changed, prev and the maple tree data should * be updated for vma_link() */ WARN_ON_ONCE(addr != vma->vm_start); @@ -1773,7 +1933,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr, goto free_vma; } - vma_link(mm, vma, prev); + mas.index = mas.last = addr; + mas_walk(&mas); + vma_mas_link(mm, vma, &mas, prev); /* Once vma denies write, undo our temporary denial count */ if (file) { unmap_writable: @@ -1783,14 +1945,14 @@ unsigned long mmap_region(struct file *file, unsigned long addr, allow_write_access(file); } file = vma->vm_file; -out: +expanded: perf_event_mmap(vma); vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); if (vm_flags & VM_LOCKED) { if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || - is_vm_hugetlb_page(vma) || - vma == get_gate_vma(current->mm)) + is_vm_hugetlb_page(vma) || + vma == get_gate_vma(current->mm)) vma->vm_flags &= VM_LOCKED_CLEAR_MASK; else mm->locked_vm += (len >> PAGE_SHIFT); @@ -2080,14 +2242,17 @@ struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, unsigned long end_addr) { struct vm_area_struct *vma; - unsigned long addr = start_addr; + 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; - vma = mt_find(&mm->mm_mt, &addr, end_addr - 1); + rcu_read_lock(); + vma = mas_find(&mas, end_addr - 1); + rcu_read_unlock(); + if (vma) vmacache_update(start_addr, vma); @@ -2616,16 +2781,13 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, arch_unmap(mm, start, end); /* Find the first overlapping VMA */ - vma = find_vma(mm, start); + vma = find_vma_intersection(mm, start, end); if (!vma) return 0; + prev = vma->vm_prev; /* we have start < vma->vm_end */ - /* if it doesn't overlap, we have nothing.. */ - if (vma->vm_start >= end) - return 0; - /* * If we need to split any vma, do it now to save pain later. * @@ -2635,7 +2797,6 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, */ if (start > vma->vm_start) { int error; - /* * Make sure that map_count on return from munmap() will * not exceed its limit; but let map_count go just above