From: Nathan Fontenot <nfont@linux.vnet.ibm.com> To: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Dave Hansen <dave@sr71.net>, Cody P Schafer <cody@linux.vnet.ibm.com>, Andrew Morton <akpm@linux-foundation.org>, Lai Jiangshan <laijs@cn.fujitsu.com>, "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC][PATCH] drivers: base: dynamic memory block creation Date: Wed, 14 Aug 2013 15:40:17 -0500 [thread overview] Message-ID: <520BEB31.6090103@linux.vnet.ibm.com> (raw) In-Reply-To: <1376508705-3188-1-git-send-email-sjenning@linux.vnet.ibm.com> On 08/14/2013 02:31 PM, Seth Jennings wrote: > Large memory systems (~1TB or more) experience boot delays on the order > of minutes due to the initializing the memory configuration part of > sysfs at /sys/devices/system/memory/. With the previous work that has been done in the memory sysfs layout I think you need machines with 8 or 16+ TB of memory to see boot delays that are measured in minutes. The boot delay is there, and with larger memory systems in he future it will only get worse. > > ppc64 has a normal memory block size of 256M (however sometimes as low > as 16M depending on the system LMB size), and (I think) x86 is 128M. With > 1TB of RAM and a 256M block size, that's 4k memory blocks with 20 sysfs > entries per block that's around 80k items that need be created at boot > time in sysfs. Some systems go up to 16TB where the issue is even more > severe. > It should also be pointed out that the number of sysfs entries created on 16+ TB system is 100k+. At his scale it is not really human readable to list all of the entries. The amount of resources used to create all of the uderlying structures for each of the entries starts to add up also. I think an approach such as this makes the sysfs memory layout more human readable and saves on resources. -Nathan
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Fontenot <nfont@linux.vnet.ibm.com> To: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Dave Hansen <dave@sr71.net>, Cody P Schafer <cody@linux.vnet.ibm.com>, Andrew Morton <akpm@linux-foundation.org>, Lai Jiangshan <laijs@cn.fujitsu.com>, "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC][PATCH] drivers: base: dynamic memory block creation Date: Wed, 14 Aug 2013 15:40:17 -0500 [thread overview] Message-ID: <520BEB31.6090103@linux.vnet.ibm.com> (raw) In-Reply-To: <1376508705-3188-1-git-send-email-sjenning@linux.vnet.ibm.com> On 08/14/2013 02:31 PM, Seth Jennings wrote: > Large memory systems (~1TB or more) experience boot delays on the order > of minutes due to the initializing the memory configuration part of > sysfs at /sys/devices/system/memory/. With the previous work that has been done in the memory sysfs layout I think you need machines with 8 or 16+ TB of memory to see boot delays that are measured in minutes. The boot delay is there, and with larger memory systems in he future it will only get worse. > > ppc64 has a normal memory block size of 256M (however sometimes as low > as 16M depending on the system LMB size), and (I think) x86 is 128M. With > 1TB of RAM and a 256M block size, that's 4k memory blocks with 20 sysfs > entries per block that's around 80k items that need be created at boot > time in sysfs. Some systems go up to 16TB where the issue is even more > severe. > It should also be pointed out that the number of sysfs entries created on 16+ TB system is 100k+. At his scale it is not really human readable to list all of the entries. The amount of resources used to create all of the uderlying structures for each of the entries starts to add up also. I think an approach such as this makes the sysfs memory layout more human readable and saves on resources. -Nathan -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2013-08-14 20:40 UTC|newest] Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-08-14 19:31 [RFC][PATCH] drivers: base: dynamic memory block creation Seth Jennings 2013-08-14 19:31 ` Seth Jennings 2013-08-14 19:40 ` Greg Kroah-Hartman 2013-08-14 19:40 ` Greg Kroah-Hartman 2013-08-16 19:07 ` Seth Jennings 2013-08-16 19:07 ` Seth Jennings 2013-08-14 19:43 ` Greg Kroah-Hartman 2013-08-14 19:43 ` Greg Kroah-Hartman 2013-08-14 20:05 ` Dave Hansen 2013-08-14 20:05 ` Dave Hansen 2013-08-14 20:35 ` Greg Kroah-Hartman 2013-08-14 20:35 ` Greg Kroah-Hartman 2013-08-14 21:16 ` Seth Jennings 2013-08-14 21:16 ` Seth Jennings 2013-08-14 21:37 ` Yinghai Lu 2013-08-14 21:52 ` Seth Jennings 2013-08-14 21:52 ` Seth Jennings 2013-08-14 23:20 ` Yinghai Lu 2013-08-14 23:20 ` Yinghai Lu 2013-08-15 2:12 ` Michael Ellerman 2013-08-15 2:12 ` Michael Ellerman 2013-08-15 2:12 ` Michael Ellerman 2013-08-14 20:40 ` Nathan Fontenot [this message] 2013-08-14 20:40 ` Nathan Fontenot 2013-08-14 20:47 ` Dave Hansen 2013-08-14 20:47 ` Dave Hansen 2013-08-14 21:14 ` Seth Jennings 2013-08-14 21:14 ` Seth Jennings 2013-08-14 21:36 ` Dave Hansen 2013-08-14 21:36 ` Dave Hansen 2013-08-14 21:37 ` Cody P Schafer 2013-08-14 21:37 ` Cody P Schafer 2013-08-14 21:49 ` Dave Hansen 2013-08-14 21:49 ` Dave Hansen 2013-08-15 0:01 ` Rafael J. Wysocki 2013-08-15 0:01 ` Rafael J. Wysocki 2013-08-16 18:41 ` Seth Jennings 2013-08-16 18:41 ` Seth Jennings
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=520BEB31.6090103@linux.vnet.ibm.com \ --to=nfont@linux.vnet.ibm.com \ --cc=akpm@linux-foundation.org \ --cc=cody@linux.vnet.ibm.com \ --cc=dave@sr71.net \ --cc=gregkh@linuxfoundation.org \ --cc=laijs@cn.fujitsu.com \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=rafael.j.wysocki@intel.com \ --cc=sjenning@linux.vnet.ibm.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.