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author | kib <kib@FreeBSD.org> | 2014-10-11 17:49:51 +0000 |
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committer | kib <kib@FreeBSD.org> | 2014-10-11 17:49:51 +0000 |
commit | 149982a012806bc520fa15bfff1a47aea2968623 (patch) | |
tree | 5a2ffe10a081c08403012d1132f6b2fcb117ce5d /sys/vm | |
parent | d9503cbf77cc30b6fd68e4206a55dafb9c9926e1 (diff) | |
download | FreeBSD-src-149982a012806bc520fa15bfff1a47aea2968623.zip FreeBSD-src-149982a012806bc520fa15bfff1a47aea2968623.tar.gz |
MFC r272536:
Add kernel option KSTACK_USAGE_PROF.
Diffstat (limited to 'sys/vm')
-rw-r--r-- | sys/vm/vm_glue.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c index 9e8995f..de2dff2 100644 --- a/sys/vm/vm_glue.c +++ b/sys/vm/vm_glue.c @@ -62,6 +62,7 @@ __FBSDID("$FreeBSD$"); #include "opt_vm.h" #include "opt_kstack_pages.h" #include "opt_kstack_max_pages.h" +#include "opt_kstack_usage_prof.h" #include <sys/param.h> #include <sys/systm.h> @@ -98,6 +99,8 @@ __FBSDID("$FreeBSD$"); #include <vm/vm_pager.h> #include <vm/swap_pager.h> +#include <machine/cpu.h> + #ifndef NO_SWAPPING static int swapout(struct proc *); static void swapclear(struct proc *); @@ -486,6 +489,52 @@ kstack_cache_init(void *nulll) SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL); +#ifdef KSTACK_USAGE_PROF +/* + * Track maximum stack used by a thread in kernel. + */ +static int max_kstack_used; + +SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD, + &max_kstack_used, 0, + "Maxiumum stack depth used by a thread in kernel"); + +void +intr_prof_stack_use(struct thread *td, struct trapframe *frame) +{ + vm_offset_t stack_top; + vm_offset_t current; + int used, prev_used; + + /* + * Testing for interrupted kernel mode isn't strictly + * needed. It optimizes the execution, since interrupts from + * usermode will have only the trap frame on the stack. + */ + if (TRAPF_USERMODE(frame)) + return; + + stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE; + current = (vm_offset_t)(uintptr_t)&stack_top; + + /* + * Try to detect if interrupt is using kernel thread stack. + * Hardware could use a dedicated stack for interrupt handling. + */ + if (stack_top <= current || current < td->td_kstack) + return; + + used = stack_top - current; + for (;;) { + prev_used = max_kstack_used; + if (prev_used >= used) + break; + if (atomic_cmpset_int(&max_kstack_used, prev_used, used)) + break; + } +} +#endif /* KSTACK_USAGE_PROF */ + #ifndef NO_SWAPPING /* * Allow a thread's kernel stack to be paged out. |