Re: [PATCH v5 1/3] mm, proc: Implement /proc/<pid>/totmaps
From: Oleg Nesterov <hidden>
Date: 2016-09-07 12:58:57
Also in:
lkml
On 09/05, robert.foss-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org wrote:
quoted hunk ↗ jump to hunk
@@ -2854,6 +2854,7 @@ static const struct pid_entry tgid_base_stuff[] = { REG("clear_refs", S_IWUSR, proc_clear_refs_operations), REG("smaps", S_IRUGO, proc_pid_smaps_operations), REG("pagemap", S_IRUSR, proc_pagemap_operations), + REG("totmaps", S_IRUGO, proc_totmaps_operations),
I must have missed something, but I fail to understand why this patch
is so complicated.
Just use ONE("totmaps", S_IRUGO, proc_totmaps_operations) ?
quoted hunk ↗ jump to hunk
+static int totmaps_proc_show(struct seq_file *m, void *data) +{ + struct proc_maps_private *priv = m->private; + struct mm_struct *mm = priv->mm; + struct vm_area_struct *vma; + struct mem_size_stats mss_sum; + + memset(&mss_sum, 0, sizeof(mss_sum)); + down_read(&mm->mmap_sem); + hold_task_mempolicy(priv);
^^^^^^^^^^^^^^^^^^^^^^^^^ why?
+ for (vma = mm->mmap; vma != priv->tail_vma; vma = vma->vm_next) {Hmm. the usage of ->tail_vma looks just wrong. I guess the code should work because it is NULL but still.
quoted hunk ↗ jump to hunk
+ struct mem_size_stats mss; + struct mm_walk smaps_walk = { + .pmd_entry = smaps_pte_range, + .mm = vma->vm_mm, + .private = &mss, + }; + + if (vma->vm_mm && !is_vm_hugetlb_page(vma)) { + memset(&mss, 0, sizeof(mss)); + walk_page_vma(vma, &smaps_walk); + add_smaps_sum(&mss, &mss_sum); + } + }
Why? I mean, why not walk_page_range() ? You do not need this for-each-vma loop at all? At least if you change this patch to use the ONE() helper, and everything else looks unneeded in this case. Oleg.