People reported that when allocating crashkernel memory using ",high" and ",low" syntax, there were cases where the reservation of the "high" portion succeeds, but the reservation of the "low" portion fails. Then kexec can load kdump kernel successfully, but the boot of kdump kernel fails as there's no low memory. This is because allocation of low memory for kdump kernel can fail on large systems for reasons. E.g it could be manually specified crashkernel low memory is too large to find in memblock region.
In this patch add return value for reserve_crashkernel_low. Then put the crashkernel low memory reserving earlier, just between finding the crashkernel high memory region and reserving crashkernel high memory. Then if crashkernel low memory reserving failed we do not reserve crashkernel high memory but return directly. Users can take measures when they found kdump kernel cann't be loaded successfully. Signed-off-by: Baoquan He <b...@redhat.com> --- arch/x86/kernel/setup.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 80f874b..b9d6f71 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -513,7 +513,7 @@ static void __init memblock_x86_reserve_range_setup_data(void) # define CRASH_KERNEL_ADDR_HIGH_MAX MAXMEM #endif -static void __init reserve_crashkernel_low(void) +static int __init reserve_crashkernel_low(void) { #ifdef CONFIG_X86_64 const unsigned long long alignment = 16<<20; /* 16M */ @@ -542,7 +542,7 @@ static void __init reserve_crashkernel_low(void) } else { /* passed with crashkernel=0,low ? */ if (!low_size) - return; + return 0; } low_base = memblock_find_in_range(low_size, (1ULL<<32), @@ -552,7 +552,7 @@ static void __init reserve_crashkernel_low(void) if (!auto_set) pr_info("crashkernel low reservation failed - No suitable area found.\n"); - return; + return EINVAL; } memblock_reserve(low_base, low_size); @@ -564,6 +564,7 @@ static void __init reserve_crashkernel_low(void) crashk_low_res.end = low_base + low_size - 1; insert_resource(&iomem_resource, &crashk_low_res); #endif + return 0; } static void __init reserve_crashkernel(void) @@ -613,6 +614,10 @@ static void __init reserve_crashkernel(void) return; } } + + if (crash_base >= (1ULL<<32) && reserve_crashkernel_low()) + return; + memblock_reserve(crash_base, crash_size); printk(KERN_INFO "Reserving %ldMB of memory at %ldMB " @@ -624,9 +629,6 @@ static void __init reserve_crashkernel(void) crashk_res.start = crash_base; crashk_res.end = crash_base + crash_size - 1; insert_resource(&iomem_resource, &crashk_res); - - if (crash_base >= (1ULL<<32)) - reserve_crashkernel_low(); } #else static void __init reserve_crashkernel(void) -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/