From: Baoquan He <bhe@redhat.com>
To: 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, bhe@redhat.com
Subject: [PATCH v3 2/5] dma-pool: allow user to disable atomic pool
Date: Mon, 13 Dec 2021 20:27:09 +0800 [thread overview]
Message-ID: <20211213122712.23805-3-bhe@redhat.com> (raw)
In-Reply-To: <20211213122712.23805-1-bhe@redhat.com>
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>
---
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);
--
2.17.2
next prev parent reply other threads:[~2021-12-13 12:27 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 ` Baoquan He [this message]
2021-12-13 14:21 ` [PATCH v3 2/5] dma-pool: allow user to disable " john.p.donnelly
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
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