diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h new file mode 100644 index 000000000000..97d635cabac8 --- /dev/null +++ b/include/trace/events/huge_memory.h @@ -0,0 +1,136 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM huge_memory + +#if !defined(__HUGE_MEMORY_H) || defined(TRACE_HEADER_MULTI_READ) +#define __HUGE_MEMORY_H + +#include + +#include + +#define SCAN_STATUS \ + EM( SCAN_FAIL, "failed") \ + EM( SCAN_SUCCEED, "succeeded") \ + EM( SCAN_PMD_NULL, "pmd_null") \ + EM( SCAN_EXCEED_NONE_PTE, "exceed_none_pte") \ + EM( SCAN_PTE_NON_PRESENT, "pte_non_present") \ + EM( SCAN_PAGE_RO, "no_writable_page") \ + EM( SCAN_NO_REFERENCED_PAGE, "no_referenced_page") \ + EM( SCAN_PAGE_NULL, "page_null") \ + EM( SCAN_SCAN_ABORT, "scan_aborted") \ + EM( SCAN_PAGE_COUNT, "not_suitable_page_count") \ + EM( SCAN_PAGE_LRU, "page_not_in_lru") \ + EM( SCAN_PAGE_LOCK, "page_locked") \ + EM( SCAN_PAGE_ANON, "page_not_anon") \ + EM( SCAN_ANY_PROCESS, "no_process_for_page") \ + EM( SCAN_VMA_NULL, "vma_null") \ + EM( SCAN_VMA_CHECK, "vma_check_failed") \ + EM( SCAN_ADDRESS_RANGE, "not_suitable_address_range") \ + EM( SCAN_SWAP_CACHE_PAGE, "page_swap_cache") \ + EM( SCAN_DEL_PAGE_LRU, "could_not_delete_page_from_lru")\ + EM( SCAN_ALLOC_HUGE_PAGE_FAIL, "alloc_huge_page_failed") \ + EMe( SCAN_CGROUP_CHARGE_FAIL, "ccgroup_charge_failed") + +#undef EM +#undef EMe +#define EM(a, b) TRACE_DEFINE_ENUM(a); +#define EMe(a, b) TRACE_DEFINE_ENUM(a); + +SCAN_STATUS + +#undef EM +#undef EMe +#define EM(a, b) {a, b}, +#define EMe(a, b) {a, b} + +TRACE_EVENT(mm_khugepaged_scan_pmd, + + TP_PROTO(struct mm_struct *mm, unsigned long pfn, bool writable, + bool referenced, int none_or_zero, int status), + + TP_ARGS(mm, pfn, writable, referenced, none_or_zero, status), + + TP_STRUCT__entry( + __field(struct mm_struct *, mm) + __field(unsigned long, pfn) + __field(bool, writable) + __field(bool, referenced) + __field(int, none_or_zero) + __field(int, status) + ), + + TP_fast_assign( + __entry->mm = mm; + __entry->pfn = pfn; + __entry->writable = writable; + __entry->referenced = referenced; + __entry->none_or_zero = none_or_zero; + __entry->status = status; + ), + + TP_printk("mm=%p, scan_pfn=0x%lx, writable=%d, referenced=%d, none_or_zero=%d, status=%s", + __entry->mm, + __entry->pfn, + __entry->writable, + __entry->referenced, + __entry->none_or_zero, + __print_symbolic(__entry->status, SCAN_STATUS)) +); + +TRACE_EVENT(mm_collapse_huge_page, + + TP_PROTO(struct mm_struct *mm, int isolated, int status), + + TP_ARGS(mm, isolated, status), + + TP_STRUCT__entry( + __field(struct mm_struct *, mm) + __field(int, isolated) + __field(int, status) + ), + + TP_fast_assign( + __entry->mm = mm; + __entry->isolated = isolated; + __entry->status = status; + ), + + TP_printk("mm=%p, isolated=%d, status=%s", + __entry->mm, + __entry->isolated, + __print_symbolic(__entry->status, SCAN_STATUS)) +); + +TRACE_EVENT(mm_collapse_huge_page_isolate, + + TP_PROTO(unsigned long pfn, int none_or_zero, + bool referenced, bool writable, int status), + + TP_ARGS(pfn, none_or_zero, referenced, writable, status), + + TP_STRUCT__entry( + __field(unsigned long, pfn) + __field(int, none_or_zero) + __field(bool, referenced) + __field(bool, writable) + __field(int, status) + ), + + TP_fast_assign( + __entry->pfn = pfn; + __entry->none_or_zero = none_or_zero; + __entry->referenced = referenced; + __entry->writable = writable; + __entry->status = status; + ), + + TP_printk("scan_pfn=0x%lx, none_or_zero=%d, referenced=%d, writable=%d, status=%s", + __entry->pfn, + __entry->none_or_zero, + __entry->referenced, + __entry->writable, + __print_symbolic(__entry->status, SCAN_STATUS)) +); + +#endif /* __HUGE_MEMORY_H */ +#include diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 62fe06bb7d04..f952f055fdcf 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -31,6 +31,33 @@ #include #include "internal.h" +enum scan_result { + SCAN_FAIL, + SCAN_SUCCEED, + SCAN_PMD_NULL, + SCAN_EXCEED_NONE_PTE, + SCAN_PTE_NON_PRESENT, + SCAN_PAGE_RO, + SCAN_NO_REFERENCED_PAGE, + SCAN_PAGE_NULL, + SCAN_SCAN_ABORT, + SCAN_PAGE_COUNT, + SCAN_PAGE_LRU, + SCAN_PAGE_LOCK, + SCAN_PAGE_ANON, + SCAN_ANY_PROCESS, + SCAN_VMA_NULL, + SCAN_VMA_CHECK, + SCAN_ADDRESS_RANGE, + SCAN_SWAP_CACHE_PAGE, + SCAN_DEL_PAGE_LRU, + SCAN_ALLOC_HUGE_PAGE_FAIL, + SCAN_CGROUP_CHARGE_FAIL +}; + +#define CREATE_TRACE_POINTS +#include + /* * By default transparent hugepage support is disabled in order that avoid * to risk increase the memory footprint of applications without a guaranteed @@ -2198,26 +2225,33 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, unsigned long address, pte_t *pte) { - struct page *page; + struct page *page = NULL; pte_t *_pte; - int none_or_zero = 0; + int none_or_zero = 0, result = 0; bool referenced = false, writable = false; + for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++, address += PAGE_SIZE) { pte_t pteval = *_pte; if (pte_none(pteval) || (pte_present(pteval) && is_zero_pfn(pte_pfn(pteval)))) { if (!userfaultfd_armed(vma) && - ++none_or_zero <= khugepaged_max_ptes_none) + ++none_or_zero <= khugepaged_max_ptes_none) { continue; - else + } else { + result = SCAN_EXCEED_NONE_PTE; goto out; + } } - if (!pte_present(pteval)) + if (!pte_present(pteval)) { + result = SCAN_PTE_NON_PRESENT; goto out; + } page = vm_normal_page(vma, address, pteval); - if (unlikely(!page)) + if (unlikely(!page)) { + result = SCAN_PAGE_NULL; goto out; + } VM_BUG_ON_PAGE(PageCompound(page), page); VM_BUG_ON_PAGE(!PageAnon(page), page); @@ -2229,8 +2263,10 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, * is needed to serialize against split_huge_page * when invoked from the VM. */ - if (!trylock_page(page)) + if (!trylock_page(page)) { + result = SCAN_PAGE_LOCK; goto out; + } /* * cannot use mapcount: can't collapse if there's a gup pin. @@ -2239,6 +2275,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, */ if (page_count(page) != 1 + !!PageSwapCache(page)) { unlock_page(page); + result = SCAN_PAGE_COUNT; goto out; } if (pte_write(pteval)) { @@ -2246,6 +2283,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, } else { if (PageSwapCache(page) && !reuse_swap_page(page)) { unlock_page(page); + result = SCAN_SWAP_CACHE_PAGE; goto out; } /* @@ -2260,6 +2298,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, */ if (isolate_lru_page(page)) { unlock_page(page); + result = SCAN_DEL_PAGE_LRU; goto out; } /* 0 stands for page_is_file_cache(page) == false */ @@ -2273,10 +2312,21 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, mmu_notifier_test_young(vma->vm_mm, address)) referenced = true; } - if (likely(referenced && writable)) - return 1; + if (likely(writable)) { + if (likely(referenced)) { + result = SCAN_SUCCEED; + trace_mm_collapse_huge_page_isolate(page_to_pfn(page), none_or_zero, + referenced, writable, result); + return 1; + } + } else { + result = SCAN_PAGE_RO; + } + out: release_pte_pages(pte, _pte); + trace_mm_collapse_huge_page_isolate(page_to_pfn(page), none_or_zero, + referenced, writable, result); return 0; } @@ -2513,7 +2563,7 @@ static void collapse_huge_page(struct mm_struct *mm, pgtable_t pgtable; struct page *new_page; spinlock_t *pmd_ptl, *pte_ptl; - int isolated; + int isolated, result = 0; unsigned long hstart, hend; struct mem_cgroup *memcg; unsigned long mmun_start; /* For mmu_notifiers */ @@ -2528,12 +2578,15 @@ static void collapse_huge_page(struct mm_struct *mm, /* release the mmap_sem read lock. */ new_page = khugepaged_alloc_page(hpage, gfp, mm, address, node); - if (!new_page) - return; + if (!new_page) { + result = SCAN_ALLOC_HUGE_PAGE_FAIL; + goto out_nolock; + } - if (unlikely(mem_cgroup_try_charge(new_page, mm, - gfp, &memcg))) - return; + if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg))) { + result = SCAN_CGROUP_CHARGE_FAIL; + goto out_nolock; + } /* * Prevent all access to pagetables with the exception of @@ -2541,21 +2594,31 @@ static void collapse_huge_page(struct mm_struct *mm, * handled by the anon_vma lock + PG_lock. */ down_write(&mm->mmap_sem); - if (unlikely(khugepaged_test_exit(mm))) + if (unlikely(khugepaged_test_exit(mm))) { + result = SCAN_ANY_PROCESS; goto out; + } vma = find_vma(mm, address); - if (!vma) + if (!vma) { + result = SCAN_VMA_NULL; goto out; + } hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK; - if (address < hstart || address + HPAGE_PMD_SIZE > hend) + if (address < hstart || address + HPAGE_PMD_SIZE > hend) { + result = SCAN_ADDRESS_RANGE; goto out; - if (!hugepage_vma_check(vma)) + } + if (!hugepage_vma_check(vma)) { + result = SCAN_VMA_CHECK; goto out; + } pmd = mm_find_pmd(mm, address); - if (!pmd) + if (!pmd) { + result = SCAN_PMD_NULL; goto out; + } anon_vma_lock_write(vma->anon_vma); @@ -2592,6 +2655,7 @@ static void collapse_huge_page(struct mm_struct *mm, pmd_populate(mm, pmd, pmd_pgtable(_pmd)); spin_unlock(pmd_ptl); anon_vma_unlock_write(vma->anon_vma); + result = SCAN_FAIL; goto out; } @@ -2629,10 +2693,15 @@ static void collapse_huge_page(struct mm_struct *mm, *hpage = NULL; khugepaged_pages_collapsed++; + result = SCAN_SUCCEED; out_up_write: up_write(&mm->mmap_sem); + trace_mm_collapse_huge_page(mm, isolated, result); return; +out_nolock: + trace_mm_collapse_huge_page(mm, isolated, result); + return; out: mem_cgroup_cancel_charge(new_page, memcg); goto out_up_write; @@ -2645,8 +2714,8 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, { pmd_t *pmd; pte_t *pte, *_pte; - int ret = 0, none_or_zero = 0; - struct page *page; + int ret = 0, none_or_zero = 0, result = 0; + struct page *page = NULL; unsigned long _address; spinlock_t *ptl; int node = NUMA_NO_NODE; @@ -2655,8 +2724,10 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, VM_BUG_ON(address & ~HPAGE_PMD_MASK); pmd = mm_find_pmd(mm, address); - if (!pmd) + if (!pmd) { + result = SCAN_PMD_NULL; goto out; + } memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load)); pte = pte_offset_map_lock(mm, pmd, address, &ptl); @@ -2665,19 +2736,25 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, pte_t pteval = *_pte; if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { if (!userfaultfd_armed(vma) && - ++none_or_zero <= khugepaged_max_ptes_none) + ++none_or_zero <= khugepaged_max_ptes_none) { continue; - else + } else { + result = SCAN_EXCEED_NONE_PTE; goto out_unmap; + } } - if (!pte_present(pteval)) + if (!pte_present(pteval)) { + result = SCAN_PTE_NON_PRESENT; goto out_unmap; + } if (pte_write(pteval)) writable = true; page = vm_normal_page(vma, _address, pteval); - if (unlikely(!page)) + if (unlikely(!page)) { + result = SCAN_PAGE_NULL; goto out_unmap; + } /* * Record which node the original page is from and save this * information to khugepaged_node_load[]. @@ -2685,26 +2762,49 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, * hit record. */ node = page_to_nid(page); - if (khugepaged_scan_abort(node)) + if (khugepaged_scan_abort(node)) { + result = SCAN_SCAN_ABORT; goto out_unmap; + } khugepaged_node_load[node]++; VM_BUG_ON_PAGE(PageCompound(page), page); - if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) + if (!PageLRU(page)) { + result = SCAN_SCAN_ABORT; goto out_unmap; + } + if (PageLocked(page)) { + result = SCAN_PAGE_LOCK; + goto out_unmap; + } + if (!PageAnon(page)) { + result = SCAN_PAGE_ANON; + goto out_unmap; + } + /* * cannot use mapcount: can't collapse if there's a gup pin. * The page must only be referenced by the scanned process * and page swap cache. */ - if (page_count(page) != 1 + !!PageSwapCache(page)) + if (page_count(page) != 1 + !!PageSwapCache(page)) { + result = SCAN_PAGE_COUNT; goto out_unmap; + } if (pte_young(pteval) || page_is_young(page) || PageReferenced(page) || mmu_notifier_test_young(vma->vm_mm, address)) referenced = true; } - if (referenced && writable) - ret = 1; + if (writable) { + if (referenced) { + result = SCAN_SUCCEED; + ret = 1; + } else { + result = SCAN_NO_REFERENCED_PAGE; + } + } else { + result = SCAN_PAGE_RO; + } out_unmap: pte_unmap_unlock(pte, ptl); if (ret) { @@ -2713,6 +2813,8 @@ out_unmap: collapse_huge_page(mm, address, hpage, vma, node); } out: + trace_mm_khugepaged_scan_pmd(mm, page_to_pfn(page), writable, referenced, + none_or_zero, result); return ret; }