virtio-mem in Linux adds/removes individual memory blocks (e.g., 128 MB each). Linux merges adjacent memory blocks added by virtio-mem devices, but we can still end up with a very sparse memory layout when unplugging memory in corner cases.
Let's increase the maximum number of crash memory ranges from ~2k to 32k. 32k should be sufficient for a very long time. e_phnum field in the header is 16 bits wide, so we can fit a maximum of ~64k entries in there, shared with other entries (i.e., CPU). Therefore, using up to 32k memory ranges is fine. (if we ever need more than ~64k, we can switch to the sh_info field) Move the temporary xen ranges off the stack, dynamically allocating memory for them. Note: We don't have to increase MAX_MEMORY_RANGES, because virtio-mem added memory is driver managed and always detected and added by a driver in the kexec'ed kernel; for ordinary kexec, we must not expose these ranges in the firmware-provided memmap. Cc: Simon Horman <[email protected]> Signed-off-by: David Hildenbrand <[email protected]> --- kexec/arch/i386/crashdump-x86.c | 6 ++++-- kexec/arch/i386/crashdump-x86.h | 3 ++- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c index 43e830a..df84185 100644 --- a/kexec/arch/i386/crashdump-x86.c +++ b/kexec/arch/i386/crashdump-x86.c @@ -355,8 +355,8 @@ static int get_crash_memory_ranges(struct memory_range **range, int *ranges, static int get_crash_memory_ranges_xen(struct memory_range **range, int *ranges, unsigned long lowmem_limit) { + struct e820entry *e820entries; int j, rc, ret = -1; - struct e820entry e820entries[CRASH_MAX_MEMORY_RANGES]; unsigned int i; xc_interface *xc; @@ -367,6 +367,8 @@ static int get_crash_memory_ranges_xen(struct memory_range **range, return -1; } + e820entries = xmalloc(sizeof(*e820entries) * CRASH_MAX_MEMORY_RANGES); + rc = xc_get_machine_memory_map(xc, e820entries, CRASH_MAX_MEMORY_RANGES); if (rc < 0) { @@ -395,7 +397,7 @@ static int get_crash_memory_ranges_xen(struct memory_range **range, err: xc_interface_close(xc); - + free(e820entries); return ret; } #else diff --git a/kexec/arch/i386/crashdump-x86.h b/kexec/arch/i386/crashdump-x86.h index e4fdc82..479a549 100644 --- a/kexec/arch/i386/crashdump-x86.h +++ b/kexec/arch/i386/crashdump-x86.h @@ -22,7 +22,8 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline, #define X86_64_KERNEL_TEXT_SIZE (512UL*1024*1024) #define CRASH_MAX_MEMMAP_NR 1024 -#define CRASH_MAX_MEMORY_RANGES (MAX_MEMORY_RANGES + 2) + +#define CRASH_MAX_MEMORY_RANGES 32768 /* Backup Region, First 640K of System RAM. */ #define BACKUP_SRC_START 0x00000000 -- 2.29.2 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
