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authorMichael Holzheu <holzheu@linux.vnet.ibm.com>2012-01-13 02:20:14 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-13 05:13:11 +0100
commit6480e5a0923756b500634d9777ec4189492fbbfe (patch)
tree0b1d26ce39f9b7cd28a9e82627ee837734f7c3ab
parentkexec: remove KMSG_DUMP_KEXEC (diff)
downloadlinux-6480e5a0923756b500634d9777ec4189492fbbfe.tar.xz
linux-6480e5a0923756b500634d9777ec4189492fbbfe.zip
kdump: add missing RAM resource in crash_shrink_memory()
When shrinking crashkernel memory using /sys/kernel/kexec_crash_size for the newly added memory no RAM resource is created at the moment. Example: $ cat /proc/iomem 00000000-bfffffff : System RAM 00000000-005b7ac3 : Kernel code 005b7ac4-009743bf : Kernel data 009bb000-00a85c33 : Kernel bss c0000000-cfffffff : Crash kernel d0000000-ffffffff : System RAM $ echo 0 > /sys/kernel/kexec_crash_size $ cat /proc/iomem 00000000-bfffffff : System RAM 00000000-005b7ac3 : Kernel code 005b7ac4-009743bf : Kernel data 009bb000-00a85c33 : Kernel bss <<-- here is System RAM missing d0000000-ffffffff : System RAM One result of this bug is that the memory chunk can never be set offline using memory hotplug. With this patch I insert a new "System RAM" resource for the released memory. Then the upper example looks like the following: $ echo 0 > /sys/kernel/kexec_crash_size $ cat /proc/iomem 00000000-bfffffff : System RAM 00000000-005b7ac3 : Kernel code 005b7ac4-009743bf : Kernel data 009bb000-00a85c33 : Kernel bss c0000000-cfffffff : System RAM <<-- new rescoure d0000000-ffffffff : System RAM And now I can set chunk c0000000-cfffffff offline. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/kexec.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 20ed47ae252f..60bf181b3eae 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1129,6 +1129,7 @@ int crash_shrink_memory(unsigned long new_size)
{
int ret = 0;
unsigned long start, end;
+ struct resource *ram_res;
mutex_lock(&kexec_mutex);
@@ -1146,6 +1147,12 @@ int crash_shrink_memory(unsigned long new_size)
goto unlock;
}
+ ram_res = kzalloc(sizeof(*ram_res), GFP_KERNEL);
+ if (!ram_res) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
@@ -1154,7 +1161,15 @@ int crash_shrink_memory(unsigned long new_size)
if ((start == end) && (crashk_res.parent != NULL))
release_resource(&crashk_res);
+
+ ram_res->start = end;
+ ram_res->end = crashk_res.end;
+ ram_res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
+ ram_res->name = "System RAM";
+
crashk_res.end = end - 1;
+
+ insert_resource(&iomem_resource, ram_res);
crash_unmap_reserved_pages();
unlock: