Messages in this thread Patch in this message | | | From | Yang Yang <> | Subject | [PATCH v8 3/6] ksm: add ksm zero pages for each process | Date | Mon, 22 May 2023 18:53:05 +0800 |
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From: xu xin <xu.xin16@zte.com.cn>
As the number of ksm zero pages is not included in ksm_merging_pages per process when enabling use_zero_pages, it's unclear of how many actual pages are merged by KSM. To let users accurately estimate their memory demands when unsharing KSM zero-pages, it's necessary to show KSM zero- pages per process. In addition, it help users to know the actual KSM profit because KSM-placed zero pages are also benefit from KSM.
since unsharing zero pages placed by KSM accurately is achieved, then tracking empty pages merging and unmerging is not a difficult thing any longer.
Since we already have /proc/<pid>/ksm_stat, just add the information of 'ksm_zero_pages' in it.
Signed-off-by: xu xin <xu.xin16@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Cc: Xiaokai Ran <ran.xiaokai@zte.com.cn> Cc: Yang Yang <yang.yang29@zte.com.cn> --- fs/proc/base.c | 1 + include/linux/ksm.h | 10 ++++++---- include/linux/mm_types.h | 9 +++++++-- mm/khugepaged.c | 2 +- mm/ksm.c | 2 +- mm/memory.c | 4 ++-- 6 files changed, 18 insertions(+), 10 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c index 05452c3b9872..e407a34a46e8 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3209,6 +3209,7 @@ static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns, seq_printf(m, "ksm_rmap_items %lu\n", mm->ksm_rmap_items); seq_printf(m, "ksm_merging_pages %lu\n", mm->ksm_merging_pages); seq_printf(m, "ksm_process_profit %ld\n", ksm_process_profit(mm)); + seq_printf(m, "ksm_zero_pages %lu\n", mm->ksm_zero_pages); mmput(mm); } diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 1adcae0205e3..ca29e95481b0 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -30,14 +30,16 @@ void __ksm_exit(struct mm_struct *mm); #define set_pte_ksm_zero(pte) pte_mkdirty(pte_mkspecial(pte)) #define is_ksm_zero_pte(pte) (is_zero_pfn(pte_pfn(pte)) && pte_dirty(pte)) extern unsigned long ksm_zero_pages; -static inline void inc_ksm_zero_pages(void) +static inline void inc_ksm_zero_pages(struct mm_struct *mm) { ksm_zero_pages++; + mm->ksm_zero_pages++; } -static inline void dec_ksm_zero_pages(void) +static inline void dec_ksm_zero_pages(struct mm_struct *mm) { ksm_zero_pages--; + mm->ksm_zero_pages--; } static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) @@ -110,11 +112,11 @@ static inline void ksm_exit(struct mm_struct *mm) #define set_pte_ksm_zero(pte) pte_mkspecial(pte) #define is_ksm_zero_pte(pte) 0 -static inline void inc_ksm_zero_pages(void) +static inline void inc_ksm_zero_pages(struct mm_struct *mm) { } -static inline void dec_ksm_zero_pages(void) +static inline void dec_ksm_zero_pages(struct mm_struct *mm) { } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 306a3d1a0fa6..14f781509812 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -777,7 +777,7 @@ struct mm_struct { #ifdef CONFIG_KSM /* * Represent how many pages of this process are involved in KSM - * merging. + * merging (not including ksm_zero_pages). */ unsigned long ksm_merging_pages; /* @@ -785,7 +785,12 @@ struct mm_struct { * including merged and not merged. */ unsigned long ksm_rmap_items; -#endif + /* + * Represent how many empty pages are merged with kernel zero + * pages when enabling KSM use_zero_pages. + */ + unsigned long ksm_zero_pages; +#endif /* CONFIG_KSM */ #ifdef CONFIG_LRU_GEN struct { /* this mm_struct is on lru_gen_mm_list */ diff --git a/mm/khugepaged.c b/mm/khugepaged.c index ba0d077b6951..5cd6ac70261e 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -713,7 +713,7 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte, ptep_clear(vma->vm_mm, address, _pte); spin_unlock(ptl); if (is_ksm_zero_pte(pteval)) - dec_ksm_zero_pages(); + dec_ksm_zero_pages(vma->vm_mm); } } else { src_page = pte_page(pteval); diff --git a/mm/ksm.c b/mm/ksm.c index 2ca7e8860faa..4e510f5c5938 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1226,7 +1226,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, } else { newpte = set_pte_ksm_zero(pfn_pte(page_to_pfn(kpage), vma->vm_page_prot)); - inc_ksm_zero_pages(); + inc_ksm_zero_pages(mm); /* * We're replacing an anonymous page with a zero page, which is * not anonymous. We need to do proper accounting otherwise we diff --git a/mm/memory.c b/mm/memory.c index 058b416adf24..2603dad833d0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1417,7 +1417,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, ptent); if (unlikely(!page)) { if (is_ksm_zero_pte(ptent)) - dec_ksm_zero_pages(); + dec_ksm_zero_pages(mm); continue; } @@ -3124,7 +3124,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) } } else { if (is_ksm_zero_pte(vmf->orig_pte)) - dec_ksm_zero_pages(); + dec_ksm_zero_pages(mm); inc_mm_counter(mm, MM_ANONPAGES); } flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); -- 2.15.2
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