Previously the size of "struct ftrace_stacks" depended upon PAGE_SIZE. For the common 4K page size, on a 64-bit system, sizeof(struct ftrace_stacks) was 32K. But for a 64K page size, sizeof(struct ftrace_stacks) was 512K.
But ftrace stack usage requirements should be invariant to page size. So let's redefine FTRACE_KSTACK_ENTRIES so that "struct ftrace_stacks" is always sized at 32K for 64-bit and 16K for 32-bit. As a side effect, it removes the PAGE_SIZE compile-time constant assumption from this code, which is required to reach the goal of boot-time page size selection. Signed-off-by: Ryan Roberts <[email protected]> --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1c69ca1f1088..d4654943b580 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2914,7 +2914,7 @@ trace_function(struct trace_array *tr, unsigned long ip, unsigned long /* Allow 4 levels of nesting: normal, softirq, irq, NMI */ #define FTRACE_KSTACK_NESTING 4 -#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING) +#define FTRACE_KSTACK_ENTRIES (SZ_4K / FTRACE_KSTACK_NESTING) struct ftrace_stack { unsigned long calls[FTRACE_KSTACK_ENTRIES]; -- 2.43.0
