]> www.infradead.org Git - users/jedix/linux-maple.git/commit
udmabuf: change folios array from kmalloc to kvmalloc
authorHuan Yang <link@vivo.com>
Wed, 18 Sep 2024 02:52:25 +0000 (10:52 +0800)
committerVivek Kasireddy <vivek.kasireddy@intel.com>
Fri, 20 Sep 2024 21:07:31 +0000 (14:07 -0700)
commit1c0844c6184e658064e14c4335885785ad3bf84b
tree1929df2189ce857afc4d25ce33b64b8347cff436
parentf0bbcc258e81288212c2092c587ae06428196598
udmabuf: change folios array from kmalloc to kvmalloc

When PAGE_SIZE 4096, MAX_PAGE_ORDER 10, 64bit machine,
page_alloc only support 4MB.
If above this, trigger this warn and return NULL.

udmabuf can change size limit, if change it to 3072(3GB), and then alloc
3GB udmabuf, will fail create.

[ 4080.876581] ------------[ cut here ]------------
[ 4080.876843] WARNING: CPU: 3 PID: 2015 at mm/page_alloc.c:4556 __alloc_pages+0x2c8/0x350
[ 4080.878839] RIP: 0010:__alloc_pages+0x2c8/0x350
[ 4080.879470] Call Trace:
[ 4080.879473]  <TASK>
[ 4080.879473]  ? __alloc_pages+0x2c8/0x350
[ 4080.879475]  ? __warn.cold+0x8e/0xe8
[ 4080.880647]  ? __alloc_pages+0x2c8/0x350
[ 4080.880909]  ? report_bug+0xff/0x140
[ 4080.881175]  ? handle_bug+0x3c/0x80
[ 4080.881556]  ? exc_invalid_op+0x17/0x70
[ 4080.881559]  ? asm_exc_invalid_op+0x1a/0x20
[ 4080.882077]  ? udmabuf_create+0x131/0x400

Because MAX_PAGE_ORDER, kmalloc can max alloc 4096 * (1 << 10), 4MB
memory, each array entry is pointer(8byte), so can save 524288 pages(2GB).

Further more, costly order(order 3) may not be guaranteed that it can be
applied for, due to fragmentation.

This patch change udmabuf array use kvmalloc_array, this can fallback
alloc into vmalloc, which can guarantee allocation for any size and does
not affect the performance of kmalloc allocations.

Signed-off-by: Huan Yang <link@vivo.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240918025238.2957823-3-link@vivo.com
drivers/dma-buf/udmabuf.c