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author | zec <zec@FreeBSD.org> | 2010-02-04 07:55:42 +0000 |
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committer | zec <zec@FreeBSD.org> | 2010-02-04 07:55:42 +0000 |
commit | 393450ca7b6226ab2ec1b9837777e0651d534a4e (patch) | |
tree | 7764b989a82fe6fe95e035ec04067054114e99ad /sys/net/vnet.c | |
parent | 6db2453429c4a733846d86797a80dc47edc2aba9 (diff) | |
download | FreeBSD-src-393450ca7b6226ab2ec1b9837777e0651d534a4e.zip FreeBSD-src-393450ca7b6226ab2ec1b9837777e0651d534a4e.tar.gz |
Instead of spamming the console on each curvnet recursion event, print
out each such call graph only once, along with a stack backtrace. This
should make kernels built with VNET_DEBUG reasonably usable again in
busy / production environments.
Introduce a new DDB command "show vnetrcrs" which dumps the whole log
of distinctive curvnet recursion events. This might be useful when
recursion reports get burried / lost too deep in the message buffer.
In the later case stack backtraces are not available.
Reviewed by: bz
MFC after: 3 days
Diffstat (limited to 'sys/net/vnet.c')
-rw-r--r-- | sys/net/vnet.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/sys/net/vnet.c b/sys/net/vnet.c index 298ffb2..26635db 100644 --- a/sys/net/vnet.c +++ b/sys/net/vnet.c @@ -37,8 +37,10 @@ __FBSDID("$FreeBSD$"); #include "opt_ddb.h" +#include "opt_kdb.h" #include <sys/param.h> +#include <sys/kdb.h> #include <sys/kernel.h> #include <sys/jail.h> #include <sys/systm.h> @@ -616,6 +618,65 @@ vnet_sysuninit(void) VNET_SYSINIT_RUNLOCK(); } +#ifdef VNET_DEBUG +struct vnet_recursion { + SLIST_ENTRY(vnet_recursion) vnr_le; + const char *prev_fn; + const char *where_fn; + int where_line; + struct vnet *old_vnet; + struct vnet *new_vnet; +}; + +static SLIST_HEAD(, vnet_recursion) vnet_recursions = + SLIST_HEAD_INITIALIZER(vnet_recursions); + +static void +vnet_print_recursion(struct vnet_recursion *vnr, int brief) +{ + + if (!brief) + printf("CURVNET_SET() recursion in "); + printf("%s() line %d, prev in %s()", vnr->where_fn, vnr->where_line, + vnr->prev_fn); + if (brief) + printf(", "); + else + printf("\n "); + printf("%p -> %p\n", vnr->old_vnet, vnr->new_vnet); +} + +void +vnet_log_recursion(struct vnet *old_vnet, const char *old_fn, int line) +{ + struct vnet_recursion *vnr; + + /* Skip already logged recursion events. */ + SLIST_FOREACH(vnr, &vnet_recursions, vnr_le) + if (vnr->prev_fn == old_fn && + vnr->where_fn == curthread->td_vnet_lpush && + vnr->where_line == line && + (vnr->old_vnet == vnr->new_vnet) == (curvnet == old_vnet)) + return; + + vnr = malloc(sizeof(*vnr), M_VNET, M_NOWAIT | M_ZERO); + if (vnr == NULL) + panic("%s: malloc failed", __func__); + vnr->prev_fn = old_fn; + vnr->where_fn = curthread->td_vnet_lpush; + vnr->where_line = line; + vnr->old_vnet = old_vnet; + vnr->new_vnet = curvnet; + + SLIST_INSERT_HEAD(&vnet_recursions, vnr, vnr_le); + + vnet_print_recursion(vnr, 0); +#ifdef KDB + kdb_backtrace(); +#endif +} +#endif /* VNET_DEBUG */ + #ifdef DDB DB_SHOW_COMMAND(vnets, db_show_vnets) { @@ -637,4 +698,14 @@ DB_SHOW_COMMAND(vnets, db_show_vnets) break; } } + +#ifdef VNET_DEBUG +DB_SHOW_COMMAND(vnetrcrs, db_show_vnetrcrs) +{ + struct vnet_recursion *vnr; + + SLIST_FOREACH(vnr, &vnet_recursions, vnr_le) + vnet_print_recursion(vnr, 1); +} #endif +#endif /* DDB */ |