From: Andrew Morton <akpm@linux-foundation.org>
To: Vladimir Davydov <vdavydov@parallels.com>
Cc: oleg@redhat.com, rientjes@google.com, cl@linux.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] fork: reset mm->pinned_vm
Date: Thu, 19 Jun 2014 13:58:20 -0700 [thread overview]
Message-ID: <20140619135820.57c4934dd613c5e723f9ca82@linux-foundation.org> (raw)
In-Reply-To: <63d594c88850aa64729fceec769681f9d1d6fa68.1403168346.git.vdavydov@parallels.com>
On Thu, 19 Jun 2014 13:07:47 +0400 Vladimir Davydov <vdavydov@parallels.com> wrote:
> mm->pinned_vm counts pages of mm's address space that were permanently
> pinned in memory by increasing their reference counter. The counter was
> introduced by commit bc3e53f682d9 ("mm: distinguish between mlocked and
> pinned pages"), while before it locked_vm had been used for such pages.
>
> Obviously, we should reset the counter on fork if !CLONE_VM, just like
> we do with locked_vm, but currently we don't. Let's fix it.
>
> ...
>
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -534,6 +534,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
> atomic_long_set(&mm->nr_ptes, 0);
> mm->map_count = 0;
> mm->locked_vm = 0;
> + mm->pinned_vm = 0;
> memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
> spin_lock_init(&mm->page_table_lock);
> mm_init_cpumask(mm);
What are the runtime effects of this? I think it is only
"/proc/pid/status:VmPin is screwed up", because we don't use vm_pinned
in rlimit checks. Yes?
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next prev parent reply other threads:[~2014-06-19 20:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-19 9:07 [PATCH 1/3] fork/exec: cleanup mm initialization Vladimir Davydov
2014-06-19 9:07 ` [PATCH 2/3] fork: reset mm->pinned_vm Vladimir Davydov
2014-06-19 20:58 ` Andrew Morton [this message]
2014-06-20 7:38 ` Vladimir Davydov
2014-06-19 9:07 ` [PATCH 3/3] fork: copy mm's vm usage counters under mmap_sem Vladimir Davydov
2014-06-19 18:15 ` [PATCH 1/3] fork/exec: cleanup mm initialization Oleg Nesterov
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