On 01/20/23 at 10:02am, Simon Horman wrote:
> On Tue, Jan 17, 2023 at 11:49:21AM +0800, Baoquan He wrote:
> > This will help understand codes on crashkernel reservations on arm64.
>
> FWIIW, I think you can fold this into the first patch.
Sure, will do.
I folded this into patch 1 at the very beginning. Then felt the added
code comments add lines of change and make the code change not so
straightforward. I admit it's from personal feeling.
>
> And, although I have no good idea at this moment, I do wonder
> if the logic can be simplified - I for one really needed the
> comments to understand the retry logic.
Got it. I will consider if I can improve the logic readability. Thanks.
>
> > Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> > ---
> > arch/arm64/mm/init.c | 13 +++++++++++++
> > 1 file changed, 13 insertions(+)
> >
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index 26a05af2bfa8..f88ad17cb20d 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -177,6 +177,10 @@ static void __init reserve_crashkernel(void)
> > crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
> > search_base, crash_max);
> > if (!crash_base) {
> > + /*
> > + * For crashkernel=size[KMG]@offset[KMG], print out failure
> > + * message if can't reserve the specified region.
> > + */
> > if (fixed_base) {
> > pr_warn("cannot reserve crashkernel region [0x%llx-0x%llx]\n",
> > search_base, crash_max);
> > @@ -188,6 +192,11 @@ static void __init reserve_crashkernel(void)
> > * high memory, the minimum required low memory will be
> > * reserved later.
> > */
> > + /*
> > + * For crashkernel=size[KMG], if the first attempt was for
> > + * low memory, fall back to high memory, the minimum required
> > + * low memory will be reserved later.
> > + */
>
> I think this duplicates the preceding comment.
> Perhaps just replace the earlier comment with this one.
>
> > if (!high && crash_max == CRASH_ADDR_LOW_MAX) {
> > crash_max = CRASH_ADDR_HIGH_MAX;
> > search_base = CRASH_ADDR_LOW_MAX;
> > @@ -195,6 +204,10 @@ static void __init reserve_crashkernel(void)
> > goto retry;
> > }
> >
> > + /*
> > + * For crashkernel=size[KMG],high, if the first attempt was for
> > + * high memory, fall back to low memory.
> > + */
> > if (high && (crash_max == CRASH_ADDR_HIGH_MAX)) {
> > crash_max = CRASH_ADDR_LOW_MAX;
> > search_base = 0;
> > --
> > 2.34.1
> >
> >
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> >
>
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