From: Rik van Riel <riel@redhat.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Amerigo Wang <amwang@redhat.com>,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
Johannes Weiner <jweiner@redhat.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
linux-mm@kvack.org
Subject: Re: [PATCH 1/3] mm: completely disable THP by transparent_hugepage=never
Date: Mon, 20 Jun 2011 12:55:53 -0400 [thread overview]
Message-ID: <4DFF7B99.2060909@redhat.com> (raw)
In-Reply-To: <20110620165035.GE20843@redhat.com>
On 06/20/2011 12:50 PM, Andrea Arcangeli wrote:
> On Tue, Jun 21, 2011 at 12:34:28AM +0800, Amerigo Wang wrote:
>> transparent_hugepage=never should mean to disable THP completely,
>> otherwise we don't have a way to disable THP completely.
>> The design is broken.
>
> We want to allow people to boot with transparent_hugepage=never but to
> still allow people to enable it later at runtime. Not sure why you
> find it broken... Your patch is just crippling down the feature with
> no gain. There is absolutely no gain to disallow root to enable THP
> later at runtime with sysfs, root can enable it anyway by writing into
> /dev/mem.
>
> Unless you're root and you enable it, it's completely disabled, so I
> don't see what you mean it's not completely disabled. Not even
> khugepaged is started, try to grep of khugepaged...
Agreed, I don't really see the reason for these patches.
Amerigo?
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Amerigo Wang <amwang@redhat.com>,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
Johannes Weiner <jweiner@redhat.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
linux-mm@kvack.org
Subject: Re: [PATCH 1/3] mm: completely disable THP by transparent_hugepage=never
Date: Mon, 20 Jun 2011 12:55:53 -0400 [thread overview]
Message-ID: <4DFF7B99.2060909@redhat.com> (raw)
In-Reply-To: <20110620165035.GE20843@redhat.com>
On 06/20/2011 12:50 PM, Andrea Arcangeli wrote:
> On Tue, Jun 21, 2011 at 12:34:28AM +0800, Amerigo Wang wrote:
>> transparent_hugepage=never should mean to disable THP completely,
>> otherwise we don't have a way to disable THP completely.
>> The design is broken.
>
> We want to allow people to boot with transparent_hugepage=never but to
> still allow people to enable it later at runtime. Not sure why you
> find it broken... Your patch is just crippling down the feature with
> no gain. There is absolutely no gain to disallow root to enable THP
> later at runtime with sysfs, root can enable it anyway by writing into
> /dev/mem.
>
> Unless you're root and you enable it, it's completely disabled, so I
> don't see what you mean it's not completely disabled. Not even
> khugepaged is started, try to grep of khugepaged...
Agreed, I don't really see the reason for these patches.
Amerigo?
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next prev parent reply other threads:[~2011-06-20 16:56 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-20 16:34 [PATCH 1/3] mm: completely disable THP by transparent_hugepage=never Amerigo Wang
2011-06-20 16:34 ` Amerigo Wang
2011-06-20 16:34 ` [PATCH 2/3] mm: make the threshold of enabling THP configurable Amerigo Wang
2011-06-20 16:34 ` Amerigo Wang
2011-06-20 16:59 ` Dave Hansen
2011-06-20 16:59 ` Dave Hansen
2011-06-20 17:23 ` Cong Wang
2011-06-20 17:23 ` Cong Wang
2011-06-20 16:59 ` Mel Gorman
2011-06-20 16:59 ` Mel Gorman
2011-06-20 17:16 ` Cong Wang
2011-06-20 17:16 ` Cong Wang
2011-06-21 9:36 ` Mel Gorman
2011-06-21 9:36 ` Mel Gorman
2011-06-22 2:41 ` Cong Wang
2011-06-22 2:41 ` Cong Wang
2011-06-22 9:16 ` Mel Gorman
2011-06-22 9:16 ` Mel Gorman
2011-06-22 10:46 ` Cong Wang
2011-06-22 10:46 ` Cong Wang
2011-06-22 11:15 ` Mel Gorman
2011-06-22 11:15 ` Mel Gorman
2011-06-22 12:34 ` Cong Wang
2011-06-22 12:34 ` Cong Wang
2011-06-20 16:34 ` [PATCH 3/3] mm: print information when THP is disabled automatically Amerigo Wang
2011-06-20 16:34 ` Amerigo Wang
2011-06-20 16:54 ` Andrea Arcangeli
2011-06-20 16:54 ` Andrea Arcangeli
2011-06-20 17:25 ` Cong Wang
2011-06-20 17:25 ` Cong Wang
2011-06-20 17:01 ` Mel Gorman
2011-06-20 17:01 ` Mel Gorman
2011-06-20 17:26 ` Cong Wang
2011-06-20 17:26 ` Cong Wang
2011-06-20 19:37 ` Andrea Arcangeli
2011-06-20 19:37 ` Andrea Arcangeli
2011-06-21 9:40 ` Mel Gorman
2011-06-21 9:40 ` Mel Gorman
2011-06-20 16:50 ` [PATCH 1/3] mm: completely disable THP by transparent_hugepage=never Andrea Arcangeli
2011-06-20 16:50 ` Andrea Arcangeli
2011-06-20 16:55 ` Rik van Riel [this message]
2011-06-20 16:55 ` Rik van Riel
2011-06-20 17:01 ` Cong Wang
2011-06-20 17:01 ` Cong Wang
2011-06-20 19:43 ` Andrea Arcangeli
2011-06-20 19:43 ` Andrea Arcangeli
2011-06-21 3:15 ` Cong Wang
2011-06-21 3:15 ` Cong Wang
2011-06-20 16:58 ` Mel Gorman
2011-06-20 16:58 ` Mel Gorman
2011-06-20 17:07 ` Cong Wang
2011-06-20 17:07 ` Cong Wang
2011-06-20 17:10 ` Rik van Riel
2011-06-20 17:10 ` Rik van Riel
2011-06-20 17:19 ` Cong Wang
2011-06-20 17:19 ` Cong Wang
2011-06-20 17:28 ` Rik van Riel
2011-06-20 17:28 ` Rik van Riel
2011-06-20 17:34 ` Cong Wang
2011-06-20 17:34 ` Cong Wang
2011-06-20 17:50 ` Rik van Riel
2011-06-20 17:50 ` Rik van Riel
2011-06-20 18:25 ` Vivek Goyal
2011-06-20 18:25 ` Vivek Goyal
2011-06-20 19:21 ` Andrea Arcangeli
2011-06-20 19:21 ` Andrea Arcangeli
2011-06-21 4:08 ` Cong Wang
2011-06-21 4:08 ` Cong Wang
2011-06-21 14:43 ` Andrea Arcangeli
2011-06-21 14:43 ` Andrea Arcangeli
2011-06-22 2:56 ` Cong Wang
2011-06-22 2:56 ` Cong Wang
2011-06-22 14:22 ` Andrea Arcangeli
2011-06-22 14:22 ` Andrea Arcangeli
2011-06-21 20:01 ` Rik van Riel
2011-06-21 20:01 ` Rik van Riel
2011-06-21 3:28 ` Cong Wang
2011-06-21 3:28 ` Cong Wang
2011-06-20 17:58 ` Eric B Munson
2011-06-21 3:36 ` Cong Wang
2011-06-21 3:36 ` Cong Wang
2011-06-20 17:59 ` Vivek Goyal
2011-06-20 17:59 ` Vivek Goyal
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