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From: Vitaly Mayatskikh on 22 Apr 2010 12:30
This patch changes crash_shrink_memory() to work with previosly added
memory region also. When shrink occurs, second region is shrunk first.

Signed-off-by: Vitaly Mayatskikh <v.mayatskih(a)gmail.com>
---
kernel/kexec.c | 55 ++++++++++++++++++++++++++++++++++++++++---------------
1 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/kernel/kexec.c b/kernel/kexec.c
index b8fd6eb..dfaa01e 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1117,10 +1117,36 @@ static void free_reserved_phys_range(unsigned long begin, unsigned long end)
}
}

+int crash_shrink_region(struct resource *crashk, unsigned long new_size)
+{
+ unsigned long start, end, size;
+
+ start = crashk->start;
+ end = crashk->end;
+ size = end - start + 1;
+
+ if (!size || new_size == size) /* Nothing to free */
+ return 0;
+
+ if (new_size > size)
+ return -EINVAL;
+
+ start = roundup(start, PAGE_SIZE);
+ end = roundup(start + new_size, PAGE_SIZE);
+
+ free_reserved_phys_range(end, crashk->end);
+
+ if (start == end)
+ release_resource(crashk);
+ crashk->end = end - 1;
+
+ return 0;
+}
+
int crash_shrink_memory(unsigned long new_size)
{
int ret = 0;
- unsigned long start, end;
+ unsigned long crash_size, low_size;

mutex_lock(&kexec_mutex);

@@ -1128,26 +1154,25 @@ int crash_shrink_memory(unsigned long new_size)
ret = -ENOENT;
goto unlock;
}
- start = crashk_res.start;
- end = crashk_res.end;

- if (new_size >= end - start + 1) {
+ crash_size = low_size = crashk_res.end - crashk_res.start + 1;
+ crash_size += crashk_res_hi.end - crashk_res_hi.start + 1;
+
+ if (crash_size == new_size)
+ goto unlock;
+ if (crash_size < new_size) {
ret = -EINVAL;
- if (new_size == end - start + 1)
- ret = 0;
goto unlock;
}

- start = roundup(start, PAGE_SIZE);
- end = roundup(start + new_size, PAGE_SIZE);
-
- free_reserved_phys_range(end, crashk_res.end);
-
- if (start == end) {
- crashk_res.end = end;
- release_resource(&crashk_res);
+ if (new_size < low_size) {
+ /* Reap crashk_res_hi */
+ ret = crash_shrink_region(&crashk_res_hi, 0);
+ if (ret)
+ goto unlock;
+ ret = crash_shrink_region(&crashk_res, new_size);
} else
- crashk_res.end = end - 1;
+ ret = crash_shrink_region(&crashk_res_hi, new_size - low_size);

unlock:
mutex_unlock(&kexec_mutex);
--
1.7.0.1

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Prev: [PATCH 4/5] x86: use second memory region for dump-capture kernel
Next: [PATCH 0/5] Add second memory region for crash kernel