From c2af2a41905efcf662b53f280f8538e5c6bd05f4 Mon Sep 17 00:00:00 2001 From: Chaitanya S Prakash Date: Thu, 23 Mar 2023 16:22:41 +0530 Subject: [PATCH] selftests/mm: add platform independent in code comments The in code comments for the selftest were made on the basis of 128TB switch, an architecture feature specific to PowerPc and x86 platforms. Keeping in mind the support added for arm64 platforms which implements a 256TB switch, a more generic explanation has been provided. Link: https://lkml.kernel.org/r/20230323105243.2807166-4-chaitanyas.prakash@arm.com Signed-off-by: Chaitanya S Prakash Cc: Aneesh Kumar K.V Cc: Kirill A. Shutemov Cc: Shuah Khan Cc: Mark Rutland Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/va_high_addr_switch.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/mm/va_high_addr_switch.c b/tools/testing/selftests/mm/va_high_addr_switch.c index 6679213effed..7cfaf4a74c57 100644 --- a/tools/testing/selftests/mm/va_high_addr_switch.c +++ b/tools/testing/selftests/mm/va_high_addr_switch.c @@ -30,8 +30,8 @@ #endif /* - * >= 128TB is the hint addr value we used to select - * large address space. + * The hint addr value is used to allocate addresses + * beyond the high address switch boundary. */ #define ADDR_MARK_128TB (1UL << 47) @@ -73,9 +73,10 @@ static struct testcase testcases[] = { }, { /* - * We should never allocate at the requested address or above it - * The len cross the 128TB boundary. Without MAP_FIXED - * we will always search in the lower address space. + * Unless MAP_FIXED is specified, allocation based on hint + * addr is never at requested address or above it, which is + * beyond high address switch boundary in this case. Instead, + * a suitable allocation is found in lower address space. */ .addr = ((void *)(ADDR_SWITCH_HINT - PAGE_SIZE)), .size = 2 * PAGE_SIZE, @@ -85,8 +86,8 @@ static struct testcase testcases[] = { }, { /* - * Exact mapping at 128TB, the area is free we should get that - * even without MAP_FIXED. + * Exact mapping at high address switch boundary, should + * be obtained even without MAP_FIXED as area is free. */ .addr = ((void *)(ADDR_SWITCH_HINT)), .size = PAGE_SIZE, -- 2.11.0