From: john.p.donnelly@oracle.com
To: Baoquan He <bhe@redhat.com>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hch@lst.de,
cl@linux.com, John.p.donnelly@oracle.com,
kexec@lists.infradead.org
Subject: Re: [PATCH v3 2/5] dma-pool: allow user to disable atomic pool
Date: Mon, 13 Dec 2021 08:21:29 -0600 [thread overview]
Message-ID: <89c24193-5826-d956-a6ec-17e18c329547@oracle.com> (raw)
In-Reply-To: <20211213122712.23805-3-bhe@redhat.com>
On 12/13/21 6:27 AM, 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.
>
> So change code to allow user to disable atomic pool by specifying
> 'coherent_pool=0'.
>
> Meanwhile, update the relevant document in kernel-parameter.txt.
>
> Signed-off-by: Baoquan He <bhe@redhat.com>
>
Acked-by: John Donnelly <john.p.donnelly@oracle.com>
Tested-by: John Donnelly <john.p.donnelly@oracle.com>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 3 ++-
> kernel/dma/pool.c | 7 +++++--
> 2 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index ec4d25e854a8..d7015309614b 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -664,7 +664,8 @@
>
> coherent_pool=nn[KMG] [ARM,KNL]
> Sets the size of memory pool for coherent, atomic dma
> - allocations. Otherwise the default size will be scaled
> + allocations. A value of 0 disables the three atomic
> + memory pool. Otherwise the default size will be scaled
> with memory capacity, while clamped between 128K and
> 1 << (PAGE_SHIFT + MAX_ORDER-1).
>
> diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
> index 5f84e6cdb78e..5a85804b5beb 100644
> --- a/kernel/dma/pool.c
> +++ b/kernel/dma/pool.c
> @@ -21,7 +21,7 @@ static struct gen_pool *atomic_pool_kernel __ro_after_init;
> static unsigned long pool_size_kernel;
>
> /* Size can be defined by the coherent_pool command line */
> -static size_t atomic_pool_size;
> +static unsigned long atomic_pool_size = -1;
>
> /* Dynamic background expansion when the atomic pool is near capacity */
> static struct work_struct atomic_pool_work;
> @@ -188,11 +188,14 @@ static int __init dma_atomic_pool_init(void)
> {
> int ret = 0;
>
> + if (!atomic_pool_size)
> + return 0;
> +
> /*
> * If coherent_pool was not used on the command line, default the pool
> * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
> */
> - if (!atomic_pool_size) {
> + if (atomic_pool_size == -1) {
> unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
> pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
> atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
next prev parent reply other threads:[~2021-12-13 14:21 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-13 12:27 [PATCH v3 0/5] Avoid requesting page from DMA zone when no managed pages Baoquan He
2021-12-13 12:27 ` [PATCH v3 1/5] docs: kernel-parameters: Update to reflect the current default size of atomic pool Baoquan He
2021-12-13 14:20 ` john.p.donnelly
2021-12-13 12:27 ` [PATCH v3 2/5] dma-pool: allow user to disable " Baoquan He
2021-12-13 14:21 ` john.p.donnelly [this message]
2021-12-13 12:27 ` [PATCH v3 3/5] mm_zone: add function to check if managed dma zone exists Baoquan He
2021-12-13 14:22 ` john.p.donnelly
2021-12-16 10:52 ` David Hildenbrand
2021-12-13 12:27 ` [PATCH v3 4/5] dma/pool: create dma atomic pool only if dma zone has managed pages Baoquan He
2021-12-13 14:23 ` john.p.donnelly
2021-12-13 12:27 ` [PATCH v3 5/5] mm/slub: do not create dma-kmalloc if no managed pages in DMA zone Baoquan He
2021-12-13 13:43 ` Hyeonggon Yoo
2021-12-14 5:32 ` Baoquan He
2021-12-14 10:09 ` Vlastimil Babka
2021-12-14 10:28 ` Christoph Lameter
2021-12-15 4:48 ` Hyeonggon Yoo
2021-12-15 7:03 ` Hyeonggon Yoo
2021-12-15 7:27 ` Christoph Hellwig
2021-12-15 10:34 ` Vlastimil Babka
2021-12-15 11:51 ` David Laight
2021-12-15 13:41 ` Baoquan He
2021-12-17 11:38 ` Hyeonggon Yoo
2021-12-20 7:32 ` Baoquan He
2022-01-07 11:56 ` Hyeonggon Yoo
2021-12-15 14:42 ` Baoquan He
2021-12-15 10:08 ` Baoquan He
2021-12-17 11:38 ` Hyeonggon Yoo
2021-12-21 8:56 ` Christoph Hellwig
2021-12-22 12:37 ` Hyeonggon Yoo
2021-12-23 8:52 ` Christoph Hellwig
2021-12-13 14:24 ` john.p.donnelly
2021-12-14 16:31 ` Christoph Hellwig
2021-12-14 17:07 ` john.p.donnelly
2021-12-15 7:27 ` Christoph Hellwig
2021-12-13 21:05 ` [PATCH v3 0/5] Avoid requesting page from DMA zone when no managed pages Andrew Morton
2021-12-14 0:35 ` Baoquan He
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=89c24193-5826-d956-a6ec-17e18c329547@oracle.com \
--to=john.p.donnelly@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=bhe@redhat.com \
--cc=cl@linux.com \
--cc=hch@lst.de \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/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: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).