Author: mjg Date: Mon Dec 16 00:07:51 2019 New Revision: 355791 URL: https://svnweb.freebsd.org/changeset/base/355791
Log: 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 Modified: head/sys/tools/vnode_if.awk Modified: head/sys/tools/vnode_if.awk ============================================================================== --- head/sys/tools/vnode_if.awk Mon Dec 16 00:06:22 2019 (r355790) +++ head/sys/tools/vnode_if.awk Mon Dec 16 00:07:51 2019 (r355791) @@ -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"); _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
