From: Robert Foss <robert.foss@collabora.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: corbet@lwn.net, akpm@linux-foundation.org, vbabka@suse.cz,
hughd@google.com, mhocko@suse.com, koct9i@gmail.com,
n-horiguchi@ah.jp.nec.com, kirill.shutemov@linux.intel.com,
john.stultz@linaro.org, minchan@kernel.org,
ross.zwisler@linux.intel.com, jmarchan@redhat.com,
hannes@cmpxchg.org, keescook@chromium.org,
viro@zeniv.linux.org.uk, mguzik@redhat.com, jdanis@google.com,
calvinowens@fb.com, adobriyan@gmail.com, ebiederm@xmission.com,
sonnyrao@chromium.org, seth.forshee@canonical.com,
tixxdz@gmail.com, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, Ben Zhang <benzh@chromium.org>,
Bryan Freed <bfreed@chromium.org>,
Filipe Brandenburger <filbranden@chromium.org>,
Jann Horn <jann@thejh.net>, Michal Hocko <mhocko@kernel.org>,
linux-api@vger.kernel.org,
Jacek Anaszewski <j.anaszewski@samsung.com>
Subject: Re: [PATCH v5 1/3] mm, proc: Implement /proc/<pid>/totmaps
Date: Mon, 12 Sep 2016 18:12:28 -0400 [thread overview]
Message-ID: <1f5541b1-cb6d-32ef-a528-56dbfb5c29b1@collabora.com> (raw)
In-Reply-To: <20160907125806.GA3849@redhat.com>
Hey Oleg!
Thanks for the feedback, I'll keep it in mind, but currently it looks
like the patch is on ice for non-implementation related reasons.
Rob.
>>
>> @@ -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) ?
>
>> +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.
>
>> + 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.
>
next prev parent reply other threads:[~2016-09-12 22:12 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-05 20:14 [PATCH v5 0/3] mm, proc: Implement /proc/<pid>/totmaps robert.foss
2016-09-05 20:14 ` [PATCH v5 1/3] " robert.foss
2016-09-07 12:58 ` Oleg Nesterov
2016-09-12 22:12 ` Robert Foss [this message]
2016-09-05 20:14 ` [PATCH v5 2/3] Documentation/filesystems: Fixed typo robert.foss
2016-09-07 23:22 ` Kees Cook
2016-09-08 0:22 ` Robert Foss
2016-09-08 6:23 ` Jonathan Corbet
2016-09-05 20:14 ` [PATCH v5 3/3] Documentation/filesystems: Added /proc/PID/totmaps documentation robert.foss
2016-09-12 12:02 ` [PATCH v5 0/3] mm, proc: Implement /proc/<pid>/totmaps Michal Hocko
2016-09-12 15:31 ` Sonny Rao
2016-09-12 17:15 ` Michal Hocko
2016-09-12 17:28 ` Sonny Rao
2016-09-13 7:12 ` Michal Hocko
2016-09-13 20:27 ` Sonny Rao
2016-09-14 9:12 ` Michal Hocko
2016-09-19 15:16 ` Robert Foss
2016-09-19 19:32 ` Michal Hocko
[not found] ` <20160919194001.GE2903@pc.thejh.net>
[not found] ` <20160919195109.GB28639@dhcp22.suse.cz>
2016-09-19 19:56 ` Jann Horn
2016-09-19 20:15 ` Sonny Rao
2016-09-20 0:27 ` Robert Foss
2016-09-20 0:29 ` Sonny Rao
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