From: Sasha Levin <sasha.levin@oracle.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/15] mm/huge_memory: use new hashtable implementation
Date: Thu, 20 Dec 2012 15:30:01 -0500 [thread overview]
Message-ID: <50D37549.4010107@oracle.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1212201224190.29839@chino.kir.corp.google.com>
On 12/20/2012 03:28 PM, David Rientjes wrote:
> On Wed, 19 Dec 2012, Sasha Levin wrote:
>
>> In this case, the downside is that you'll waste 8KB if hugepages aren't available,
>> but the upside is that you'll have one less dereference when accessing the
>> hashtable.
>>
>> If the 8KB saving is preferable here I'll drop the patch and come back when
>> dynamic hashtable is supported.
>>
>
> If a distro releases with CONFIG_TRANSPARNET_HUGEPAGE=y and a user is
> running on a processor that does not support pse then this just cost them
> 8KB for no reason. The overhead by simply enabling
> CONFIG_TRANSPARENT_HUGEPAGE is worse in this scenario, but this is whole
> reason for having the dynamic allocation in the original code. If there's
> a compelling reason for why we want this change, then that fact should at
> least be documented.
>
> Could you propose a v2 that includes fixes for the other problems that
> were mentioned?
>
Sure, will do.
Thanks,
Sasha
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WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <sasha.levin@oracle.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/15] mm/huge_memory: use new hashtable implementation
Date: Thu, 20 Dec 2012 15:30:01 -0500 [thread overview]
Message-ID: <50D37549.4010107@oracle.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1212201224190.29839@chino.kir.corp.google.com>
On 12/20/2012 03:28 PM, David Rientjes wrote:
> On Wed, 19 Dec 2012, Sasha Levin wrote:
>
>> In this case, the downside is that you'll waste 8KB if hugepages aren't available,
>> but the upside is that you'll have one less dereference when accessing the
>> hashtable.
>>
>> If the 8KB saving is preferable here I'll drop the patch and come back when
>> dynamic hashtable is supported.
>>
>
> If a distro releases with CONFIG_TRANSPARNET_HUGEPAGE=y and a user is
> running on a processor that does not support pse then this just cost them
> 8KB for no reason. The overhead by simply enabling
> CONFIG_TRANSPARENT_HUGEPAGE is worse in this scenario, but this is whole
> reason for having the dynamic allocation in the original code. If there's
> a compelling reason for why we want this change, then that fact should at
> least be documented.
>
> Could you propose a v2 that includes fixes for the other problems that
> were mentioned?
>
Sure, will do.
Thanks,
Sasha
next prev parent reply other threads:[~2012-12-20 20:30 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-17 15:01 [PATCH 01/15] userns: use new hashtable implementation Sasha Levin
2012-12-17 15:01 ` [PATCH 02/15] mm,ksm: " Sasha Levin
2012-12-17 15:01 ` Sasha Levin
2012-12-18 3:25 ` Hugh Dickins
2012-12-18 3:25 ` Hugh Dickins
2012-12-17 15:01 ` [PATCH 03/15] workqueue: " Sasha Levin
2012-12-18 17:24 ` Tejun Heo
2012-12-17 15:01 ` [PATCH 04/15] mm/huge_memory: " Sasha Levin
2012-12-17 15:01 ` Sasha Levin
2012-12-19 22:26 ` David Rientjes
2012-12-19 22:26 ` David Rientjes
2012-12-20 2:25 ` Sasha Levin
2012-12-20 2:25 ` Sasha Levin
2012-12-20 20:28 ` David Rientjes
2012-12-20 20:28 ` David Rientjes
2012-12-20 20:30 ` Sasha Levin [this message]
2012-12-20 20:30 ` Sasha Levin
2012-12-17 15:01 ` [PATCH 05/15] tracepoint: " Sasha Levin
2012-12-17 15:48 ` Steven Rostedt
2012-12-17 15:01 ` [PATCH 06/15] net,9p: " Sasha Levin
2012-12-17 15:01 ` [PATCH 07/15] block,elevator: " Sasha Levin
2012-12-17 15:18 ` Jens Axboe
2012-12-17 15:01 ` [PATCH 08/15] SUNRPC/cache: " Sasha Levin
2012-12-17 15:01 ` [Cluster-devel] [PATCH 09/15] dlm: " Sasha Levin
2012-12-17 15:01 ` Sasha Levin
2012-12-17 15:01 ` [PATCH 10/15] net,l2tp: " Sasha Levin
2012-12-17 15:01 ` [PATCH 11/15] dm: " Sasha Levin
2013-01-11 18:49 ` Sasha Levin
2012-12-17 15:01 ` [PATCH 12/15] lockd: " Sasha Levin
2012-12-17 15:01 ` [PATCH 13/15] net,rds: " Sasha Levin
2012-12-17 15:01 ` [PATCH 14/15] openvswitch: " Sasha Levin
2012-12-17 15:01 ` [PATCH 15/15] tracing output: " Sasha Levin
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