aboutsummaryrefslogtreecommitdiff
path: root/sys/tools
diff options
context:
space:
mode:
authorMateusz Guzik <mjg@FreeBSD.org>2019-12-16 00:07:51 +0000
committerMateusz Guzik <mjg@FreeBSD.org>2019-12-16 00:07:51 +0000
commit61f67f32c714638adb441ab95257f2c3531387bd (patch)
treebf2b1ef989d248ad68387a9079d7b04b91025695 /sys/tools
parent6fa079fc3f5e7e120f166420c6f0c60f701ba9ae (diff)
downloadsrc-61f67f32c714638adb441ab95257f2c3531387bd.tar.gz
src-61f67f32c714638adb441ab95257f2c3531387bd.zip
vfs: allow tail call optimisation in vops in the common case
Most frequently used vops boil down to checking SDT probes, doing the call and checking again. There is no vop_post/pre in their case but the check after the call prevents tail call optimisation from taking place. Instead, check once upfront. Kernels with debug or vops with non-empty vop_post still don't short circuit. Reviewed by: kib Tested by: pho Differential Revision: https://reviews.freebsd.org/D22739
Notes
Notes: svn path=/head/; revision=355791
Diffstat (limited to 'sys/tools')
-rw-r--r--sys/tools/vnode_if.awk18
1 files changed, 11 insertions, 7 deletions
diff --git a/sys/tools/vnode_if.awk b/sys/tools/vnode_if.awk
index 39f7f6013a0b..df3251090b99 100644
--- a/sys/tools/vnode_if.awk
+++ b/sys/tools/vnode_if.awk
@@ -363,16 +363,20 @@ while ((getline < srcfile) > 0) {
printc("\tVNASSERT(a->a_gen.a_desc == &" name "_desc, a->a_" args[0]",");
printc("\t (\"Wrong a_desc in " name "(%p, %p)\", a->a_" args[0]", a));");
printc("\tVNASSERT(vop != NULL, a->a_" args[0]", (\"No "name"(%p, %p)\", a->a_" args[0]", a));")
- printc("\tSDT_PROBE2(vfs, vop, " name ", entry, a->a_" args[0] ", a);\n");
- for (i = 0; i < numargs; ++i)
- add_debug_code(name, args[i], "Entry", "\t");
printc("\tKTR_START" ctrstr);
add_pre(name);
- printc("\tif (vop->"name" != NULL)")
+ for (i = 0; i < numargs; ++i)
+ add_debug_code(name, args[i], "Entry", "\t");
+ printc("\tif (__predict_true(!SDT_PROBES_ENABLED() && vop->"name" != NULL)) {");
printc("\t\trc = vop->"name"(a);")
- printc("\telse")
- printc("\t\trc = vop->vop_bypass(&a->a_gen);")
- printc("\tSDT_PROBE3(vfs, vop, " name ", return, a->a_" args[0] ", a, rc);\n");
+ printc("\t} else {")
+ printc("\t\tSDT_PROBE2(vfs, vop, " name ", entry, a->a_" args[0] ", a);");
+ printc("\t\tif (vop->"name" != NULL)")
+ printc("\t\t\trc = vop->"name"(a);")
+ printc("\t\telse")
+ printc("\t\t\trc = vop->vop_bypass(&a->a_gen);")
+ printc("\t\tSDT_PROBE3(vfs, vop, " name ", return, a->a_" args[0] ", a, rc);");
+ printc("\t}")
printc("\tif (rc == 0) {");
for (i = 0; i < numargs; ++i)
add_debug_code(name, args[i], "OK", "\t\t");