From: Baoquan He <bhe@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, robin.murphy@arm.com, cl@linux.com,
penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com,
vbabka@suse.cz, m.szyprowski@samsung.com,
John.p.donnelly@oracle.com, kexec@lists.infradead.org
Subject: Re: [PATCH RESEND v2 2/5] dma-pool: allow user to disable atomic pool
Date: Mon, 13 Dec 2021 16:16:41 +0800 [thread overview]
Message-ID: <20211213081641.GB29905@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20211213074404.GA20758@lst.de>
On 12/13/21 at 08:44am, Christoph Hellwig wrote:
> On Tue, Dec 07, 2021 at 11:07:47AM +0800, Baoquan He wrote:
> > In the current code, three atomic memory pools are always created,
> > atomic_pool_kernel|dma|dma32, even though 'coherent_pool=0' is
> > specified in kernel command line. In fact, atomic pool is only
> > necessary when CONFIG_DMA_DIRECT_REMAP=y or mem_encrypt_active=y
> > which are needed on few ARCHes.
>
> And only these select the atomic pool, so it won't get created otherwise.
> What problem are you trying to solve?
This tries to make "coherent_pool=0" behave normally. As you see,
'coherent_pool=0' will behave like no 'coherent_pool' being specified.
This is not consistent with other similar kernel parameter, e.g cma=.
At the beginning, I planned to add a knob to allow user to disable one
or all atomic pool. Later I changed. However I think this patch makes
sense on fixing the a little bizarre behaviour, 'coherent_pool=0' but
still get atomic pool created.
I can drop it if you think it's unnecessary.
next prev parent reply other threads:[~2021-12-13 8:17 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-07 3:07 [PATCH RESEND v2 0/5] Avoid requesting page from DMA zone when no managed pages Baoquan He
2021-12-07 3:07 ` [PATCH RESEND v2 1/5] docs: kernel-parameters: Update to reflect the current default size of atomic pool Baoquan He
2021-12-07 3:53 ` John Donnelly
2021-12-07 3:07 ` [PATCH RESEND v2 2/5] dma-pool: allow user to disable " Baoquan He
2021-12-07 3:53 ` John Donnelly
2021-12-13 7:44 ` Christoph Hellwig
2021-12-13 8:16 ` Baoquan He [this message]
2021-12-07 3:07 ` [PATCH RESEND v2 3/5] mm_zone: add function to check if managed dma zone exists Baoquan He
2021-12-07 3:53 ` John Donnelly
2021-12-07 11:23 ` David Hildenbrand
2021-12-09 13:02 ` Baoquan He
2021-12-09 13:10 ` David Hildenbrand
2021-12-09 13:23 ` Baoquan He
2021-12-07 3:07 ` [PATCH RESEND v2 4/5] dma/pool: create dma atomic pool only if dma zone has managed pages Baoquan He
2021-12-07 3:54 ` John Donnelly
2021-12-07 3:07 ` [PATCH RESEND v2 5/5] mm/slub: do not create dma-kmalloc if no managed pages in DMA zone Baoquan He
2021-12-07 3:54 ` John Donnelly
2021-12-07 3:16 ` [PATCH RESEND v2 0/5] Avoid requesting page from DMA zone when no managed pages Baoquan He
2021-12-07 4:03 ` John Donnelly
2021-12-08 4:33 ` Andrew Morton
2021-12-08 4:56 ` John Donnelly
2021-12-13 3:54 ` Baoquan He
[not found] ` <YbdJ00wRFvi0aqze@zn.tnic>
2021-12-13 14:03 ` Baoquan He
2021-12-07 8:05 ` Christoph Lameter
2021-12-09 8:05 ` Baoquan He
2021-12-09 12:59 ` Christoph Lameter
2021-12-13 7:39 ` Baoquan He
2021-12-13 7:49 ` Christoph Hellwig
2021-12-13 7:47 ` Christoph Hellwig
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