Extend smap_gather_stats to support indicated beginning address at which it should start gathering. To achieve the goal, we add a new parameter @start assigned by the caller and try to refactor it for simplicity. If @start is 0, it will use the range of @vma for gathering. Change since v2: - This is a new change to make the retry behavior of smaps_rollup - more complete as suggested by Michel [1] [1] https://lore.kernel.org/lkml/CANN689FtCsC71cjAjs0GPspOhgo_HRj+diWsoU1wr98YPktgWg@xxxxxxxxxxxxxx/ Signed-off-by: Chinwen Chang <chinwen.chang@xxxxxxxxxxxx> CC: Michel Lespinasse <walken@xxxxxxxxxx> Reviewed-by: Steven Price <steven.price@xxxxxxx> --- fs/proc/task_mmu.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index dbda449..76e623a 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -723,9 +723,21 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, .pte_hole = smaps_pte_hole, }; +/* + * Gather mem stats from @vma with the indicated beginning + * address @start, and keep them in @mss. + * + * Use vm_start of @vma as the beginning address if @start is 0. + */ static void smap_gather_stats(struct vm_area_struct *vma, - struct mem_size_stats *mss) + struct mem_size_stats *mss, unsigned long start) { + const struct mm_walk_ops *ops = &smaps_walk_ops; + + /* Invalid start */ + if (start >= vma->vm_end) + return; + #ifdef CONFIG_SHMEM /* In case of smaps_rollup, reset the value from previous vma */ mss->check_shmem_swap = false; @@ -742,18 +754,20 @@ static void smap_gather_stats(struct vm_area_struct *vma, */ unsigned long shmem_swapped = shmem_swap_usage(vma); - if (!shmem_swapped || (vma->vm_flags & VM_SHARED) || - !(vma->vm_flags & VM_WRITE)) { + if (!start && (!shmem_swapped || (vma->vm_flags & VM_SHARED) || + !(vma->vm_flags & VM_WRITE))) { mss->swap += shmem_swapped; } else { mss->check_shmem_swap = true; - walk_page_vma(vma, &smaps_shmem_walk_ops, mss); - return; + ops = &smaps_shmem_walk_ops; } } #endif /* mmap_lock is held in m_start */ - walk_page_vma(vma, &smaps_walk_ops, mss); + if (!start) + walk_page_vma(vma, ops, mss); + else + walk_page_range(vma->vm_mm, start, vma->vm_end, ops, mss); } #define SEQ_PUT_DEC(str, val) \ @@ -805,7 +819,7 @@ static int show_smap(struct seq_file *m, void *v) memset(&mss, 0, sizeof(mss)); - smap_gather_stats(vma, &mss); + smap_gather_stats(vma, &mss, 0); show_map_vma(m, vma); @@ -854,7 +868,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v) hold_task_mempolicy(priv); for (vma = priv->mm->mmap; vma; vma = vma->vm_next) { - smap_gather_stats(vma, &mss); + smap_gather_stats(vma, &mss, 0); last_vma_end = vma->vm_end; } -- 1.9.1
