From d280a26a983f62bfeff3f134f9d5ba4035356b43 Mon Sep 17 00:00:00 2001 From: "Mike Rapoport (Microsoft)" Date: Thu, 28 May 2026 12:53:00 +0300 Subject: xor: use kmalloc() in calibrate_xor_blocks() Patch series "lib/raid: replace __get_free_pages() call with kmalloc()", v4. The xor benchmark allocates 4 pages for a scratch buffer that is used purely as a CPU-only XOR working area. This buffer can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API than ancient __get_free_pages(). kmalloc() does not require ugly casts and kfree() does not need to know the size of the freed object. There is no performance difference because kmalloc() redirects allocations of such size to the page allocator. Replace __get_free_pages() call with kmalloc(). This patch (of 2): The xor benchmark allocates 4 pages for a scratch buffer that is used purely as a CPU-only XOR working area. This buffer can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API than ancient __get_free_pages(). kmalloc() does not require ugly casts and kfree() does not need to know the size of the freed object. There is no performance difference because kmalloc() redirects allocations of such size to the page allocator. Replace __get_free_pages() call with kmalloc(). Link: https://lore.kernel.org/20260528-lib-v4-0-4e3ad1277279@kernel.org Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Link: https://lore.kernel.org/20260528-lib-v4-1-4e3ad1277279@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Cc: Christoph Hellwig Cc: Li Nan Cc: Song Liu Signed-off-by: Andrew Morton --- lib/raid/xor/xor-core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/raid/xor/xor-core.c b/lib/raid/xor/xor-core.c index bd4e6e434418..50931fbf0324 100644 --- a/lib/raid/xor/xor-core.c +++ b/lib/raid/xor/xor-core.c @@ -8,6 +8,7 @@ #include #include +#include #include #include #include @@ -114,7 +115,7 @@ static int __init calibrate_xor_blocks(void) if (forced_template) return 0; - b1 = (void *) __get_free_pages(GFP_KERNEL, 2); + b1 = kmalloc(PAGE_SIZE * 4, GFP_KERNEL); if (!b1) { pr_warn("xor: Yikes! No memory available.\n"); return -ENOMEM; @@ -132,7 +133,7 @@ static int __init calibrate_xor_blocks(void) pr_info("xor: using function: %s (%d MB/sec)\n", fastest->name, fastest->speed); - free_pages((unsigned long)b1, 2); + kfree(b1); return 0; } -- cgit v1.2.3