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From: Gregory Price <gregory.price@memverge.com>
To: Shesha Bhushan Sreenivasamurthy <sheshas@marvell.com>
Cc: "linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>
Subject: Re: DAX system-ram usage by the kernel
Date: Wed, 1 Feb 2023 19:35:18 -0500	[thread overview]
Message-ID: <Y9sFRvrI5024NxUj@memverge.com> (raw)
In-Reply-To: <DM6PR18MB2844A9ED953484909A27850EAFD69@DM6PR18MB2844.namprd18.prod.outlook.com>

On Thu, Feb 02, 2023 at 05:56:21PM +0000, Shesha Bhushan Sreenivasamurthy wrote:
> 
> 
> 
> From: Shesha Bhushan Sreenivasamurthy <sheshas@marvell.com>
> Sent: Thursday, February 2, 2023 9:35 AM
> To: linux-cxl@vger.kernel.org <linux-cxl@vger.kernel.org>
> Subject: DAX system-ram usage by the kernel 
>  
> Hello All,
>     When a CXL memory is assigned as system-ram using daxctl after boot, can kernel allocate memory from this memory range which cannot be moved and prevent this device from being made offline ?
> 
> After some reading, i found that this memory's valid zone will be "movable" and not "normal". Therefore, kernel's kmalloc, mmp and page-tables will only allocate from normal zone. Correct me if I am wrong.
> 
> Thanks,
> Shesha.

There are a variety of reasons that moveable zones can fail to offline.

https://docs.kernel.org/admin-guide/mm/memory-hotplug.html#memory-offlining-and-zone-movable

  reply	other threads:[~2023-02-02 18:47 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-02 17:35 DAX system-ram usage by the kernel Shesha Bhushan Sreenivasamurthy
2023-02-02 17:56 ` Shesha Bhushan Sreenivasamurthy
2023-02-02  0:35   ` Gregory Price [this message]
2023-02-07 18:23 ` Dan Williams

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