From: "ying.huang@intel.com" <ying.huang@intel.com>
To: Jagdish Gediya <jvgediya@linux.ibm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com,
baolin.wang@linux.alibaba.com, dave.hansen@linux.intel.com
Subject: Re: [PATCH v2 1/5] mm: demotion: Set demotion list differently
Date: Thu, 14 Apr 2022 16:57:04 +0800 [thread overview]
Message-ID: <d330a8942933e7c0fd4ea35b2c96948cd034aae2.camel@intel.com> (raw)
In-Reply-To: <YlffwGJg/RWCYja7@li-6e1fa1cc-351b-11b2-a85c-b897023bb5f3.ibm.com>
On Thu, 2022-04-14 at 14:18 +0530, Jagdish Gediya wrote:
> On Thu, Apr 14, 2022 at 03:09:42PM +0800, ying.huang@intel.com wrote:
> > On Wed, 2022-04-13 at 14:52 +0530, Jagdish Gediya wrote:
> > > Sharing used_targets between multiple nodes in a single
> > > pass limits some of the opportunities for demotion target
> > > sharing.
> > >
> > > Don't share the used targets between multiple nodes in a
> > > single pass, instead accumulate all the used targets in
> > > source nodes shared by all pass, and reset 'used_targets'
> > > to source nodes while finding demotion targets for any new
> > > node.
> > >
> > > This results into some more opportunities to share demotion
> > > targets between multiple source nodes, e.g. with below NUMA
> > > topology, where node 0 & 1 are cpu + dram nodes, node 2 & 3
> > > are equally slower memory only nodes, and node 4 is slowest
> > > memory only node,
> > >
> > > available: 5 nodes (0-4)
> > > node 0 cpus: 0 1
> > > node 0 size: n MB
> > > node 0 free: n MB
> > > node 1 cpus: 2 3
> > > node 1 size: n MB
> > > node 1 free: n MB
> > > node 2 cpus:
> > > node 2 size: n MB
> > > node 2 free: n MB
> > > node 3 cpus:
> > > node 3 size: n MB
> > > node 3 free: n MB
> > > node 4 cpus:
> > > node 4 size: n MB
> > > node 4 free: n MB
> > > node distances:
> > > node 0 1 2 3 4
> > > 0: 10 20 40 40 80
> > > 1: 20 10 40 40 80
> > > 2: 40 40 10 40 80
> > > 3: 40 40 40 10 80
> > > 4: 80 80 80 80 10
> > >
> > > The existing implementation gives below demotion targets,
> > >
> > > node demotion_target
> > > 0 3, 2
> > > 1 4
> > > 2 X
> > > 3 X
> > > 4 X
> > >
> > > With this patch applied, below are the demotion targets,
> > >
> > > node demotion_target
> > > 0 3, 2
> > > 1 3, 2
> > > 2 4
> > > 3 4
> > > 4 X
> > >
> > > e.g. with below NUMA topology, where node 0, 1 & 2 are
> > > cpu + dram nodes and node 3 is slow memory node,
> > >
> > > available: 4 nodes (0-3)
> > > node 0 cpus: 0 1
> > > node 0 size: n MB
> > > node 0 free: n MB
> > > node 1 cpus: 2 3
> > > node 1 size: n MB
> > > node 1 free: n MB
> > > node 2 cpus: 4 5
> > > node 2 size: n MB
> > > node 2 free: n MB
> > > node 3 cpus:
> > > node 3 size: n MB
> > > node 3 free: n MB
> > > node distances:
> > > node 0 1 2 3
> > > 0: 10 20 20 40
> > > 1: 20 10 20 40
> > > 2: 20 20 10 40
> > > 3: 40 40 40 10
> > >
> > > The existing implementation gives below demotion targets,
> > >
> > > node demotion_target
> > > 0 3
> > > 1 X
> > > 2 X
> > > 3 X
> > >
> > > With this patch applied, below are the demotion targets,
> > >
> > > node demotion_target
> > > 0 3
> > > 1 3
> > > 2 3
> > > 3 X
> > >
> >
> > With the [PATCH v1], you have describe the demotion order changes for
> > the following system, I guess there's no change with [PATCH v2]?
>
> Yes, there is no change with v2.
>
> > With below NUMA topology, where node 0 & 2 are cpu + dram
> > nodes and node 1 & 3 are slow memory nodes,
> >
> > available: 4 nodes (0-3)
> > node 0 cpus: 0 1
> > node 0 size: n MB
> > node 0 free: n MB
> > node 1 cpus:
> > node 1 size: n MB
> > node 1 free: n MB
> > node 2 cpus: 2 3
> > node 2 size: n MB
> > node 2 free: n MB
> > node 3 cpus:
> > node 3 size: n MB
> > node 3 free: n MB
> > node distances:
> > node 0 1 2 3
> > 0: 10 40 20 80
> > 1: 40 10 80 80
> > 2: 20 80 10 40
> > 3: 80 80 40 10
> >
> > And, what is the demotion order for the following system with [PATCH
> > v2]?
> >
> > Node 0 & 2 are cpu + dram nodes and node 1 are slow
> > memory node near node 0,
> >
> > available: 3 nodes (0-2)
> > node 0 cpus: 0 1
> > node 0 size: n MB
> > node 0 free: n MB
> > node 1 cpus:
> > node 1 size: n MB
> > node 1 free: n MB
> > node 2 cpus: 2 3
> > node 2 size: n MB
> > node 2 free: n MB
> > node distances:
> > node 0 1 2
> > 0: 10 40 20
> > 1: 40 10 80
> > 2: 20 80 10
>
> node 1 is demotion target for both node 0 and node 2 with this patch.
> node 1 is demotion target only for node 0 with existing implementation,
> however if node 1 is near to node 2 instead of node 0, still existing
> implementation will give node 1 as demotion target only for node 0 which
> is not the correct behavior.
>
> for both the scenario, with this patch applied, node 1 will be demotion
> target for both 0 and 2.
>
Sounds good! Thanks.
Acked-by: "Huang, Ying" <ying.huang@intel.com>
> > Best Regards,
> > Huang, Ying
> >
> >
> > [snip]
> >
> >
> >
> Best regards,
> Jagdish
next prev parent reply other threads:[~2022-04-14 8:57 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-13 9:22 [PATCH v2 0/5] mm: demotion: Introduce new node state N_DEMOTION_TARGETS Jagdish Gediya
2022-04-13 9:22 ` [PATCH v2 1/5] mm: demotion: Set demotion list differently Jagdish Gediya
2022-04-14 7:09 ` ying.huang
2022-04-14 8:48 ` Jagdish Gediya
2022-04-14 8:57 ` ying.huang [this message]
2022-04-14 8:55 ` Baolin Wang
2022-04-14 9:02 ` Jonathan Cameron
2022-04-14 10:40 ` Jagdish Gediya
2022-04-21 6:13 ` ying.huang
2022-04-13 9:22 ` [PATCH v2 2/5] mm: demotion: Add new node state N_DEMOTION_TARGETS Jagdish Gediya
2022-04-21 4:33 ` Wei Xu
2022-04-13 9:22 ` [PATCH v2 3/5] mm: demotion: Add support to set targets from userspace Jagdish Gediya
2022-04-21 4:26 ` Wei Xu
2022-04-22 9:13 ` Jagdish Gediya
2022-04-21 5:31 ` Wei Xu
2022-04-13 9:22 ` [PATCH v2 4/5] device-dax/kmem: Set node state as N_DEMOTION_TARGETS Jagdish Gediya
2022-04-13 9:22 ` [PATCH v2 5/5] mm: demotion: Build demotion list based on N_DEMOTION_TARGETS Jagdish Gediya
2022-04-13 21:44 ` [PATCH v2 0/5] mm: demotion: Introduce new node state N_DEMOTION_TARGETS Andrew Morton
2022-04-14 10:16 ` Jagdish Gediya
2022-04-14 7:00 ` ying.huang
2022-04-14 10:19 ` Jagdish Gediya
2022-04-21 3:11 ` Yang Shi
2022-04-21 5:41 ` Wei Xu
2022-04-21 6:24 ` ying.huang
2022-04-21 6:49 ` Wei Xu
2022-04-21 7:08 ` ying.huang
2022-04-21 7:29 ` Wei Xu
2022-04-21 7:45 ` ying.huang
2022-04-21 18:26 ` Wei Xu
2022-04-22 0:58 ` ying.huang
2022-04-22 4:46 ` Wei Xu
2022-04-22 5:40 ` ying.huang
2022-04-22 6:13 ` Wei Xu
2022-04-22 6:21 ` ying.huang
2022-04-22 11:00 ` Jagdish Gediya
2022-04-22 16:43 ` Wei Xu
2022-04-22 17:29 ` Yang Shi
2022-04-24 3:02 ` ying.huang
2022-04-25 3:50 ` Aneesh Kumar K.V
2022-04-25 6:10 ` ying.huang
2022-04-25 8:09 ` Aneesh Kumar K V
2022-04-25 8:54 ` Aneesh Kumar K V
2022-04-25 20:17 ` Davidlohr Bueso
2022-04-26 8:42 ` ying.huang
2022-04-26 9:02 ` Aneesh Kumar K V
2022-04-26 9:44 ` ying.huang
2022-04-27 4:27 ` Wei Xu
2022-04-25 7:26 ` Jagdish Gediya
2022-04-25 16:56 ` Wei Xu
2022-04-27 5:06 ` Aneesh Kumar K V
2022-04-27 18:27 ` Wei Xu
2022-04-28 0:56 ` ying.huang
2022-04-28 4:11 ` Wei Xu
2022-04-28 17:14 ` Yang Shi
2022-04-29 1:27 ` Alistair Popple
2022-04-29 2:21 ` ying.huang
2022-04-29 2:58 ` Wei Xu
2022-04-29 3:27 ` ying.huang
2022-04-29 4:45 ` Alistair Popple
2022-04-29 18:53 ` Yang Shi
2022-04-29 18:52 ` Yang Shi
2022-04-27 7:11 ` ying.huang
2022-04-27 16:27 ` Wei Xu
2022-04-28 8:37 ` ying.huang
[not found] ` <DM6PR11MB4107867291AFE0C210D9052ADCFD9@DM6PR11MB4107.namprd11.prod.outlook.com>
2022-04-30 2:21 ` Wei Xu
2022-04-21 17:56 ` Yang Shi
2022-04-21 23:48 ` ying.huang
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