Re: [PATCH 06/17] x86/numa: simplify numa_distance allocation
From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Date: 2024-07-19 16:28:54
Also in:
linux-acpi, linux-arch, linux-arm-kernel, linux-cxl, linux-devicetree, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, lkml, loongarch, nvdimm, sparclinux
On Tue, 16 Jul 2024 14:13:35 +0300 Mike Rapoport [off-list ref] wrote:
From: "Mike Rapoport (Microsoft)" <rppt@kernel.org> Allocation of numa_distance uses memblock_phys_alloc_range() to limit allocation to be below the last mapped page. But NUMA initializaition runs after the direct map is populated and
initialization (one too many 'i's)
there is also code in setup_arch() that adjusts memblock limit to reflect how much memory is already mapped in the direct map. Simplify the allocation of numa_distance and use plain memblock_alloc(). This makes the code clearer and ensures that when numa_distance is not allocated it is always NULL.
Doesn't this break the comment in numa_set_distance() kernel-doc? " * If such table cannot be allocated, a warning is printed and further * calls are ignored until the distance table is reset with * numa_reset_distance(). " Superficially that looks to be to avoid repeatedly hitting the singleton bit at the top of numa_set_distance() as SRAT or similar parsing occurs.
quoted hunk ↗ jump to hunk
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> --- arch/x86/mm/numa.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index 5e1dde26674b..ab2d4ecef786 100644 --- a/arch/x86/mm/numa.c +++ b/arch/x86/mm/numa.c@@ -319,8 +319,7 @@ void __init numa_reset_distance(void) { size_t size = numa_distance_cnt * numa_distance_cnt * sizeof(numa_distance[0]); - /* numa_distance could be 1LU marking allocation failure, test cnt */ - if (numa_distance_cnt) + if (numa_distance) memblock_free(numa_distance, size); numa_distance_cnt = 0; numa_distance = NULL; /* enable table creation */@@ -331,7 +330,6 @@ static int __init numa_alloc_distance(void) nodemask_t nodes_parsed; size_t size; int i, j, cnt = 0; - u64 phys; /* size the new table and allocate it */ nodes_parsed = numa_nodes_parsed;@@ -342,16 +340,12 @@ static int __init numa_alloc_distance(void) cnt++; size = cnt * cnt * sizeof(numa_distance[0]); - phys = memblock_phys_alloc_range(size, PAGE_SIZE, 0, - PFN_PHYS(max_pfn_mapped)); - if (!phys) { + numa_distance = memblock_alloc(size, PAGE_SIZE); + if (!numa_distance) { pr_warn("Warning: can't allocate distance table!\n"); - /* don't retry until explicitly reset */ - numa_distance = (void *)1LU; return -ENOMEM; } - numa_distance = __va(phys); numa_distance_cnt = cnt; /* fill with the default distances */