From: Vlastimil Babka <vbabka@suse.cz>
To: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
linux-mm <linux-mm@kvack.org>,
lkml <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH] mm: introduce MADV_CLR_HUGEPAGE
Date: Wed, 24 May 2017 13:31:12 +0200 [thread overview]
Message-ID: <aec1376e-34b3-56ce-448e-7fbddcda448b@suse.cz> (raw)
In-Reply-To: <20170524103947.GC3063@rapoport-lnx>
On 05/24/2017 12:39 PM, Mike Rapoport wrote:
>> Hm so the prctl does:
>>
>> if (arg2)
>> me->mm->def_flags |= VM_NOHUGEPAGE;
>> else
>> me->mm->def_flags &= ~VM_NOHUGEPAGE;
>>
>> That's rather lazy implementation IMHO. Could we change it so the flag
>> is stored elsewhere in the mm, and the code that decides to (not) use
>> THP will check both the per-vma flag and the per-mm flag?
>
> I afraid I don't understand how that can help.
> What we need is an ability to temporarily disable collapse of the pages in
> VMAs that do not have VM_*HUGEPAGE flags set and that after we re-enable
> THP, the vma->vm_flags for those VMAs will remain intact.
That's what I'm saying - instead of implementing the prctl flag via
mm->def_flags (which gets permanently propagated to newly created vma's
but e.g. doesn't affect already existing ones), it would be setting a
flag somewhere in mm, which khugepaged (and page faults) would check in
addition to the per-vma flags.
> --
> Sincerely yours,
> Mike.
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
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next prev parent reply other threads:[~2017-05-24 11:31 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1495433562-26625-1-git-send-email-rppt@linux.vnet.ibm.com>
[not found] ` <20170522114243.2wrdbncilozygbpl@node.shutemov.name>
[not found] ` <20170522133559.GE27382@rapoport-lnx>
[not found] ` <20170522135548.GA8514@dhcp22.suse.cz>
[not found] ` <20170522142927.GG27382@rapoport-lnx>
[not found] ` <a9e74c22-1a07-f49a-42b5-497fee85e9c9@suse.cz>
[not found] ` <20170524075043.GB3063@rapoport-lnx>
2017-05-24 7:58 ` [PATCH] mm: introduce MADV_CLR_HUGEPAGE Vlastimil Babka
2017-05-24 10:39 ` Mike Rapoport
2017-05-24 11:18 ` Michal Hocko
2017-05-24 14:25 ` Pavel Emelyanov
2017-05-24 14:27 ` Mike Rapoport
2017-05-24 15:22 ` Andrea Arcangeli
2017-05-30 7:44 ` Michal Hocko
[not found] ` <20170530074408.GA7969-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-30 10:19 ` Mike Rapoport
2017-05-30 10:39 ` Michal Hocko
[not found] ` <20170530103930.GB7969-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-30 14:04 ` Andrea Arcangeli
2017-05-30 14:39 ` Michal Hocko
[not found] ` <20170530143941.GK7969-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-30 14:56 ` Michal Hocko
[not found] ` <20170530145632.GL7969-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-30 16:06 ` Andrea Arcangeli
2017-05-31 6:30 ` Vlastimil Babka
2017-05-31 8:24 ` Michal Hocko
2017-05-31 9:27 ` Mike Rapoport
2017-05-31 10:24 ` Michal Hocko
[not found] ` <20170531082414.GB27783-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-31 10:22 ` Michal Hocko
2017-06-01 11:00 ` Mike Rapoport
2017-06-01 12:27 ` Michal Hocko
2017-05-30 15:43 ` Andrea Arcangeli
2017-05-31 12:08 ` Michal Hocko
[not found] ` <20170531120822.GL27783-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-05-31 12:39 ` Mike Rapoprt
2017-05-31 14:18 ` Andrea Arcangeli
[not found] ` <20170531141809.GB302-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-05-31 14:32 ` Michal Hocko
2017-05-31 15:46 ` Andrea Arcangeli
2017-06-01 6:58 ` Mike Rapoport
[not found] ` <8FA5E4C2-D289-4AF5-AA09-6C199E58F9A5-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2017-05-31 14:19 ` Michal Hocko
2017-06-01 6:53 ` Mike Rapoport
2017-06-01 8:09 ` Michal Hocko
[not found] ` <20170601080909.GD32677-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-06-01 8:35 ` Mike Rapoport
2017-06-01 13:45 ` Andrea Arcangeli
2017-06-02 9:11 ` Mike Rapoport
2017-05-31 9:08 ` Mike Rapoport
2017-05-31 12:05 ` Michal Hocko
2017-05-31 12:25 ` Mike Rapoprt
2017-05-24 11:31 ` Vlastimil Babka [this message]
2017-05-24 14:28 ` Pavel Emelyanov
2017-05-24 14:54 ` Vlastimil Babka
2017-05-24 15:13 ` Mike Rapoport
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