On 2023/3/20 22:36, Simon Horman wrote:
On Tue, Mar 21, 2023 at 04:42:43AM +0800, Chen Jiahao wrote:
On riscv, the current crash kernel allocation logic is trying to
allocate within 32bit addressible memory region by default, if
failed, try to allocate without 4G restriction.
In need of saving DMA zone memory while allocating a relatively large
crash kernel region, allocating the reserved memory top down in
high memory, without overlapping the DMA zone, is a mature solution.
Here introduce the parameter option crashkernel=X,[high,low].
We can reserve the crash kernel from high memory above DMA zone range
by explicitly passing "crashkernel=X,high"; or reserve a memory range
below 4G with "crashkernel=X,low".
Signed-off-by: Chen Jiahao <chenjiahao16@xxxxxxxxxx>
Some minor nits, but I don't think there is any need to respin for them.
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
I will send another version and clean up these by the way, thanks.
Chen, Jiahao
...
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 478d6763a01a..5def2174b243 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
...
@@ -1201,16 +1242,25 @@ static void __init reserve_crashkernel(void)
*/
crash_base = memblock_phys_alloc_range(crash_size, PMD_SIZE,
search_start,
- min(search_end, (unsigned long) SZ_4G));
+ min(search_end, (unsigned long) dma32_phys_limit));
nit: While here, you could drop the space before 'ma32_phys_limit'.
Or perhaps use min_t, which seems appropriate here.
if (crash_base == 0) {
/* Try again without restricting region to 32bit addressible memory */
crash_base = memblock_phys_alloc_range(crash_size, PMD_SIZE,
- search_start, search_end);
+ search_start, search_end);
if (crash_base == 0) {
pr_warn("crashkernel: couldn't allocate %lldKB\n",
crash_size >> 10);
return;
}
+
+ if (!crash_low_size)
+ crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
+ }
+
+ if ((crash_base > dma32_phys_limit - crash_low_size) &&
+ crash_low_size && reserve_crashkernel_low(crash_low_size)) {
nit: The line above should be aligned one character to the left
(remove one space in the indent).
+ memblock_phys_free(crash_base, crash_size);
+ return;
}
pr_info("crashkernel: reserved 0x%016llx - 0x%016llx (%lld MB)\n",
...
