Date: Fri, 6 Dec 2019 16:34:04 +0000 (UTC) From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r355448 - head/sys/kern Message-ID: <201912061634.xB6GY4gf042266@repo.freebsd.org>
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Author: bz Date: Fri Dec 6 16:34:04 2019 New Revision: 355448 URL: https://svnweb.freebsd.org/changeset/base/355448 Log: Improve EPOCH_TRACE Two changes to EPOCH_TRACE: (1) add a sysctl to surpress the backtrace from epoch_trace_report(). Sometimes the log line for the recursion is enough and the backtrace massively spams the console. (2) In order to be able to go without the backtrace do not only print where the previous occurance happened, but also where the current one happens. That way we have file:line information for both and can look at them without the need for getting line numbers from backtrace and a debugging tool. Reviewed by: glebius Sponsored by: Netflix (originally) Differential Revision: https://reviews.freebsd.org/D22641 Modified: head/sys/kern/subr_epoch.c Modified: head/sys/kern/subr_epoch.c ============================================================================== --- head/sys/kern/subr_epoch.c Fri Dec 6 16:20:22 2019 (r355447) +++ head/sys/kern/subr_epoch.c Fri Dec 6 16:34:04 2019 (r355448) @@ -169,6 +169,10 @@ RB_GENERATE_STATIC(stacktree, stackentry, se_node, sta static struct mtx epoch_stacks_lock; MTX_SYSINIT(epochstacks, &epoch_stacks_lock, "epoch_stacks", MTX_DEF); +static bool epoch_trace_stack_print = true; +SYSCTL_BOOL(_kern_epoch, OID_AUTO, trace_stack_print, CTLFLAG_RWTUN, + &epoch_trace_stack_print, 0, "Print stack traces on epoch reports"); + static void epoch_trace_report(const char *fmt, ...) __printflike(1, 2); static inline void epoch_trace_report(const char *fmt, ...) @@ -197,7 +201,8 @@ epoch_trace_report(const char *fmt, ...) va_start(ap, fmt); (void)vprintf(fmt, ap); va_end(ap); - stack_print_ddb(&se.se_stack); + if (epoch_trace_stack_print) + stack_print_ddb(&se.se_stack); } static inline void @@ -209,8 +214,9 @@ epoch_trace_enter(struct thread *td, epoch_t epoch, ep SLIST_FOREACH(iet, &td->td_epochs, et_tlink) if (iet->et_epoch == epoch) epoch_trace_report("Recursively entering epoch %s " - "previously entered at %s:%d\n", - epoch->e_name, iet->et_file, iet->et_line); + "at %s:%d, previously entered at %s:%d\n", + epoch->e_name, file, line, + iet->et_file, iet->et_line); et->et_epoch = epoch; et->et_file = file; et->et_line = line; @@ -223,9 +229,10 @@ epoch_trace_exit(struct thread *td, epoch_t epoch, epo { if (SLIST_FIRST(&td->td_epochs) != et) { - epoch_trace_report("Exiting epoch %s in a not nested order. " - "Most recently entered %s at %s:%d\n", + epoch_trace_report("Exiting epoch %s in a not nested order " + "at %s:%d. Most recently entered %s at %s:%d\n", epoch->e_name, + file, line, SLIST_FIRST(&td->td_epochs)->et_epoch->e_name, SLIST_FIRST(&td->td_epochs)->et_file, SLIST_FIRST(&td->td_epochs)->et_line);
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