From 2fd86a07c9ac50dfbc5eef3c69ef6e5d370f3b28 Mon Sep 17 00:00:00 2001 From: Kairui Song Date: Tue, 2 Aug 2022 01:31:55 +0800 Subject: mm/util: reduce stack usage of folio_mapcount folio_test_hugetlb() will call PageHeadHuge which is a function call, and blocks the compiler from recognizing this redundant load. After rearranging the code, stack usage is dropped from 32 to 24, and the function size is smaller (tested on GCC 12): Before: Stack usage: mm/util.c:845:5:folio_mapcount 32 static Size: 0000000000000ea0 00000000000000c7 T folio_mapcount After: Stack usage: mm/util.c:845:5:folio_mapcount 24 static Size: 0000000000000ea0 00000000000000b0 T folio_mapcount Link: https://lkml.kernel.org/r/20220801173155.92008-1-ryncsn@gmail.com Signed-off-by: Kairui Song Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index c9439c66d8cf..f0cf92b8826e 100644 --- a/mm/util.c +++ b/mm/util.c @@ -850,10 +850,10 @@ int folio_mapcount(struct folio *folio) return atomic_read(&folio->_mapcount) + 1; compound = folio_entire_mapcount(folio); - nr = folio_nr_pages(folio); if (folio_test_hugetlb(folio)) return compound; ret = compound; + nr = folio_nr_pages(folio); for (i = 0; i < nr; i++) ret += atomic_read(&folio_page(folio, i)->_mapcount) + 1; /* File pages has compound_mapcount included in _mapcount */ -- cgit From 44b414c8715c5dcf53288ce9005d7b24cc90eaf5 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Tue, 26 Jul 2022 22:54:28 +0800 Subject: mm/util.c: add warning if __vm_enough_memory fails If a process has not enough memory to allocate a new virtual mapping, we may meet verious kinds of error, eg, fork cannot allocate memory, SIGBUS error in shmem, but it is difficult to confirm them, let's add some debug information to easily to check this scenario if __vm_enough_memory fails. Link: https://lkml.kernel.org/r/20220726145428.8030-1-wangkefeng.wang@huawei.com Reported-by: Yongqiang Liu Signed-off-by: Kefeng Wang Acked-by: David Hildenbrand Signed-off-by: Andrew Morton --- mm/util.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index f0cf92b8826e..8d944ce71e94 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1052,6 +1052,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) if (percpu_counter_read_positive(&vm_committed_as) < allowed) return 0; error: + pr_warn_ratelimited("%s: pid: %d, comm: %s, no enough memory for the allocation\n", + __func__, current->pid, current->comm); vm_unacct_memory(pages); return -ENOMEM; -- cgit From 524e00b36e8c547f5582eef3fb645a8d9fc5e3df Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Tue, 6 Sep 2022 19:48:48 +0000 Subject: mm: remove rb tree. Remove the RB tree and start using the maple tree for vm_area_struct tracking. Drop validate_mm() calls in expand_upwards() and expand_downwards() as the lock is not held. Link: https://lkml.kernel.org/r/20220906194824.2110408-18-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/util.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 8d944ce71e94..10effe256dfa 100644 --- a/mm/util.c +++ b/mm/util.c @@ -288,6 +288,8 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, vma->vm_next = next; if (next) next->vm_prev = vma; + else + mm->highest_vm_end = vm_end_gap(vma); } void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma) @@ -300,8 +302,14 @@ void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma) prev->vm_next = next; else mm->mmap = next; - if (next) + if (next) { next->vm_prev = prev; + } else { + if (prev) + mm->highest_vm_end = vm_end_gap(prev); + else + mm->highest_vm_end = 0; + } } /* Check if the vma is being used as a stack by this task */ -- cgit From 763ecb035029f500d7e6dc99acd1ad299b7726a1 Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Tue, 6 Sep 2022 19:49:06 +0000 Subject: mm: remove the vma linked list Replace any vm_next use with vma_find(). Update free_pgtables(), unmap_vmas(), and zap_page_range() to use the maple tree. Use the new free_pgtables() and unmap_vmas() in do_mas_align_munmap(). At the same time, alter the loop to be more compact. Now that free_pgtables() and unmap_vmas() take a maple tree as an argument, rearrange do_mas_align_munmap() to use the new tree to hold the vmas to remove. Remove __vma_link_list() and __vma_unlink_list() as they are exclusively used to update the linked list. Drop linked list update from __insert_vm_struct(). Rework validation of tree as it was depending on the linked list. [yang.lee@linux.alibaba.com: fix one kernel-doc comment] Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=1949 Link: https://lkml.kernel.org/r/20220824021918.94116-1-yang.lee@linux.alibaba.comLink: https://lkml.kernel.org/r/20220906194824.2110408-69-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Signed-off-by: Yang Li Tested-by: Yu Zhao Cc: Catalin Marinas Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: "Matthew Wilcox (Oracle)" Cc: SeongJae Park Cc: Sven Schnelle Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/util.c | 40 ---------------------------------------- 1 file changed, 40 deletions(-) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 10effe256dfa..5cd3f7910f2c 100644 --- a/mm/util.c +++ b/mm/util.c @@ -272,46 +272,6 @@ void *memdup_user_nul(const void __user *src, size_t len) } EXPORT_SYMBOL(memdup_user_nul); -void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, - struct vm_area_struct *prev) -{ - struct vm_area_struct *next; - - vma->vm_prev = prev; - if (prev) { - next = prev->vm_next; - prev->vm_next = vma; - } else { - next = mm->mmap; - mm->mmap = vma; - } - vma->vm_next = next; - if (next) - next->vm_prev = vma; - else - mm->highest_vm_end = vm_end_gap(vma); -} - -void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma) -{ - struct vm_area_struct *prev, *next; - - next = vma->vm_next; - prev = vma->vm_prev; - if (prev) - prev->vm_next = next; - else - mm->mmap = next; - if (next) { - next->vm_prev = prev; - } else { - if (prev) - mm->highest_vm_end = vm_end_gap(prev); - else - mm->highest_vm_end = 0; - } -} - /* Check if the vma is being used as a stack by this task */ int vma_is_stack_for_current(struct vm_area_struct *vma) { -- cgit