On 09/27/2010 04:34 PM, H. Peter Anvin wrote:
> On 09/27/2010 04:32 PM, Yinghai Lu wrote:
>> On 09/27/2010 04:26 PM, H. Peter Anvin wrote:
>>> On 09/27/2010 04:20 PM, Yinghai Lu wrote:
>>>>
>>>> x86 own version for find_area?
>>>>
>>>
>>> No, double no.
>>>
>>> Same kind of crap: overloading an interface with semantics it shouldn't
>>> have. The right thing is to introduce a new interface with carries the
>>> explicitly needed policy with it... e.g. memblock_find_in_range_lowest().
>>>
>>> That interface would have the explicit semantics of returning the lowest
>>> possible address, as opposed to any suitable address (which may change
>>> if policy requirements change.)
>>>
>>> The other question is why does kexec need this in the first place? Is
>>> this due to a design bug in kexec or is there some fundamental reason
>>> for this?
>>
>> bzImage is used here. so need range below 4g.
>>
>
> OK, so why don't you cap the range to 4 GiB and then pass that down to
> the existing interface? That's different from "lowest possible address".
but if later bzImage will use 64 entry and kexec honor it, or use 64bit vmlinux directly.
and crashkernel=4096M, we could get failure again.
maybe something like this, will give it a try, hope kexec doesn't have other limitation.
[PATCH -v3] x86, memblock: Fix crashkernel allocation
Cai Qian found crashkernel is broken with x86 memblock changes
1. crashkernel=128M at 32M always reported that range is used, even first kernel is small
no one use that range
2. always get following report when using "kexec -p"
Could not find a free area of memory of a000 bytes...
locate_hole failed
The root cause is that generic memblock_find_in_range() will try to get range from top_down.
But crashkernel do need from low and specified range.
Let's limit the target range with rash_base + crash_size to make sure that
We get range from bottom.
-v3: don't use loop for find low one
Reported-and-Bisected-by: CAI Qian <caiqian at redhat.com>
Signed-off-by: Yinghai Lu <yinghai at kernel.org>
---
arch/x86/kernel/setup.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -518,17 +518,23 @@ static void __init reserve_crashkernel(v
if (crash_base <= 0) {
const unsigned long long alignment = 16<<20; /* 16M */
- crash_base = memblock_find_in_range(alignment, ULONG_MAX, crash_size,
- alignment);
+ crash_base = memblock_find_in_range(alignment, 0xffffffff,
+ crash_size, alignment);
+
if (crash_base == MEMBLOCK_ERROR) {
- pr_info("crashkernel reservation failed - No suitable area found.\n");
- return;
+ crash_base = memblock_find_in_range(alignment,
+ ULONG_MAX, crash_size, alignment);
+
+ if (crash_base == MEMBLOCK_ERROR) {
+ pr_info("crashkernel reservation failed - No suitable area found.\n");
+ return;
+ }
}
} else {
unsigned long long start;
- start = memblock_find_in_range(crash_base, ULONG_MAX, crash_size,
- 1<<20);
+ start = memblock_find_in_range(crash_base,
+ crash_base + crash_size, crash_size, 1<<20);
if (start != crash_base) {
pr_info("crashkernel reservation failed - memory is in use.\n");
return;
