The following commit has been merged into the x86/boot branch of tip: Commit-ID: 2d6bff31399b2443aba230cd20f120acb2d4eeb1 Gitweb: https://git.kernel.org/tip/2d6bff31399b2443aba230cd20f120acb2d4eeb1 Author: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx> AuthorDate: Fri, 14 Feb 2025 11:06:48 +02:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Fri, 21 Feb 2025 16:05:00 +01:00 x86/boot: Move setting of memblock parameters to e820__memblock_setup() Changing memblock parameters, namely bottom_up and allocation upper limit does not have any effect before memblock initialization in e820__memblock_setup(). Move the calls to memblock_set_bottom_up() and memblock_set_current_limit() to e820__memblock_setup() to group all the memblock initial setup and make setup_arch() more readable. No functional changes. Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20250214090651.3331663-2-rppt@xxxxxxxxxx --- arch/x86/kernel/e820.c | 30 ++++++++++++++++++++++++++++++ arch/x86/kernel/setup.c | 25 ------------------------- 2 files changed, 30 insertions(+), 25 deletions(-) diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 82b96ed..8d8bd03 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -1302,6 +1302,36 @@ void __init e820__memblock_setup(void) int i; u64 end; +#ifdef CONFIG_MEMORY_HOTPLUG + /* + * Memory used by the kernel cannot be hot-removed because Linux + * cannot migrate the kernel pages. When memory hotplug is + * enabled, we should prevent memblock from allocating memory + * for the kernel. + * + * ACPI SRAT records all hotpluggable memory ranges. But before + * SRAT is parsed, we don't know about it. + * + * The kernel image is loaded into memory at very early time. We + * cannot prevent this anyway. So on NUMA system, we set any + * node the kernel resides in as un-hotpluggable. + * + * Since on modern servers, one node could have double-digit + * gigabytes memory, we can assume the memory around the kernel + * image is also un-hotpluggable. So before SRAT is parsed, just + * allocate memory near the kernel image to try the best to keep + * the kernel away from hotpluggable memory. + */ + if (movable_node_is_enabled()) + memblock_set_bottom_up(true); +#endif + + /* + * At this point only the first megabyte is mapped for sure, the + * rest of the memory cannot be used for memblock resizing + */ + memblock_set_current_limit(ISA_END_ADDRESS); + /* * The bootstrap memblock region count maximum is 128 entries * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index cebee31..4baadea 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -866,30 +866,6 @@ void __init setup_arch(char **cmdline_p) if (efi_enabled(EFI_BOOT)) efi_memblock_x86_reserve_range(); -#ifdef CONFIG_MEMORY_HOTPLUG - /* - * Memory used by the kernel cannot be hot-removed because Linux - * cannot migrate the kernel pages. When memory hotplug is - * enabled, we should prevent memblock from allocating memory - * for the kernel. - * - * ACPI SRAT records all hotpluggable memory ranges. But before - * SRAT is parsed, we don't know about it. - * - * The kernel image is loaded into memory at very early time. We - * cannot prevent this anyway. So on NUMA system, we set any - * node the kernel resides in as un-hotpluggable. - * - * Since on modern servers, one node could have double-digit - * gigabytes memory, we can assume the memory around the kernel - * image is also un-hotpluggable. So before SRAT is parsed, just - * allocate memory near the kernel image to try the best to keep - * the kernel away from hotpluggable memory. - */ - if (movable_node_is_enabled()) - memblock_set_bottom_up(true); -#endif - x86_report_nx(); apic_setup_apic_calls(); @@ -990,7 +966,6 @@ void __init setup_arch(char **cmdline_p) cleanup_highmap(); - memblock_set_current_limit(ISA_END_ADDRESS); e820__memblock_setup(); /*
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