From: David Rientjes <rientjes@google.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Michal Hocko <mhocko@suse.com>,
linux-kernel@vger.kernel.org,
Linux-MM layout <linux-mm@kvack.org>,
Linux API <linux-api@vger.kernel.org>
Subject: Re: [patch] mm, thp: always specify ineligible vmas as nh in smaps
Date: Mon, 24 Sep 2018 12:17:34 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.21.1809241215170.239142@chino.kir.corp.google.com> (raw)
In-Reply-To: <e2f159f3-5373-dda4-5904-ed24d029de3c@suse.cz>
On Mon, 24 Sep 2018, Vlastimil Babka wrote:
> > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> > --- a/fs/proc/task_mmu.c
> > +++ b/fs/proc/task_mmu.c
> > @@ -653,13 +653,23 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
> > #endif
> > #endif /* CONFIG_ARCH_HAS_PKEYS */
> > };
> > + unsigned long flags = vma->vm_flags;
> > size_t i;
> >
> > + /*
> > + * Disabling thp is possible through both MADV_NOHUGEPAGE and
> > + * PR_SET_THP_DISABLE. Both historically used VM_NOHUGEPAGE. Since
> > + * the introduction of MMF_DISABLE_THP, however, userspace needs the
> > + * ability to detect vmas where thp is not eligible in the same manner.
> > + */
> > + if (vma->vm_mm && test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
> > + flags |= VM_NOHUGEPAGE;
>
> Should it also clear VM_HUGEPAGE? In case MMF_DISABLE_THP overrides a
> madvise(MADV_HUGEPAGE)'d vma? (I expect it does?)
>
Good point, I think that is should because MMF_DISABLE_THP will override
VM_HUGEPAGE. It looks like the Documentation file is still referencing
both as advise flags and doesn't address PR_SET_THP_DISABLE. Let me send
a v2 with a Documentation update and your suggested fix. Thanks
Vlastimil!
> > +
> > seq_puts(m, "VmFlags: ");
> > for (i = 0; i < BITS_PER_LONG; i++) {
> > if (!mnemonics[i][0])
> > continue;
> > - if (vma->vm_flags & (1UL << i)) {
> > + if (flags & (1UL << i)) {
> > seq_putc(m, mnemonics[i][0]);
> > seq_putc(m, mnemonics[i][1]);
> > seq_putc(m, ' ');
> >
next prev parent reply other threads:[~2018-09-24 19:17 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-24 17:55 [patch] mm, thp: always specify ineligible vmas as nh in smaps David Rientjes
2018-09-24 18:25 ` Vlastimil Babka
2018-09-24 19:17 ` David Rientjes [this message]
2018-09-24 19:30 ` [patch v2] " David Rientjes
2018-09-24 19:56 ` Michal Hocko
2018-09-24 20:02 ` Michal Hocko
2018-09-24 20:43 ` Vlastimil Babka
2018-09-25 5:50 ` Michal Hocko
2018-09-25 19:52 ` David Rientjes
2018-09-25 20:29 ` Michal Hocko
2018-09-25 21:45 ` David Rientjes
2018-09-25 22:04 ` Andrew Morton
2018-09-26 0:55 ` David Rientjes
2018-09-26 6:06 ` Michal Hocko
2018-10-02 11:28 ` [RFC PATCH] mm, proc: report PR_SET_THP_DISABLE in proc Michal Hocko
2018-10-02 20:29 ` David Rientjes
2018-10-03 7:36 ` Michal Hocko
2018-10-03 22:51 ` David Rientjes
2018-10-04 5:58 ` Michal Hocko
2018-10-04 9:15 ` David Rientjes
2018-10-04 9:46 ` Michal Hocko
2018-10-04 18:34 ` David Rientjes
2018-10-09 8:33 ` Michal Hocko
2018-10-15 15:03 ` Michal Hocko
2018-10-15 22:25 ` David Rientjes
2018-10-16 10:48 ` Michal Hocko
2018-10-16 21:24 ` David Rientjes
2018-10-17 7:05 ` Michal Hocko
2018-10-17 19:59 ` David Rientjes
2018-10-18 7:00 ` Michal Hocko
2018-11-14 13:23 ` Michal Hocko
2018-11-14 21:41 ` David Rientjes
2018-11-15 9:02 ` Michal Hocko
2018-11-15 9:22 ` Michal Hocko
2018-11-19 22:05 ` David Rientjes
2018-11-20 7:48 ` Michal Hocko
2018-10-03 17:33 ` Mike Rapoport
2018-09-25 21:50 ` [patch v3] mm, thp: always specify disabled vmas as nh in smaps David Rientjes
2018-09-26 6:12 ` Michal Hocko
2018-09-26 7:17 ` Michal Hocko
2018-09-26 8:40 ` Vlastimil Babka
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