From: Nicholas Clark <nick@ccl4.org>
Date: Sun, 19 Apr 2009 19:04:09 +0000 (+0100)
Subject: In the context of PERL_OLD_COPY_ON_WRITE, remove comments about global mutexes.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=327014894ced3ae73d401ac084a318bdc616e5d8;p=p5sagit%2Fp5-mst-13.2.git

In the context of PERL_OLD_COPY_ON_WRITE, remove comments about global mutexes.
These would only have been relevant if running under 5005 threads, which is long
dead.
---

diff --git a/sv.c b/sv.c
index 68caa6d..17371cb 100644
--- a/sv.c
+++ b/sv.c
@@ -4085,12 +4085,6 @@ Perl_sv_setsv_flags(pTHX_ SV *dstr, register SV* sstr, const I32 flags)
             }
 #ifdef PERL_OLD_COPY_ON_WRITE
             if (!isSwipe) {
-                /* I believe I should acquire a global SV mutex if
-                   it's a COW sv (not a shared hash key) to stop
-                   it going un copy-on-write.
-                   If the source SV has gone un copy on write between up there
-                   and down here, then (assert() that) it is of the correct
-                   form to make it copy on write again */
                 if ((sflags & (SVf_FAKE | SVf_READONLY))
                     != (SVf_FAKE | SVf_READONLY)) {
                     SvREADONLY_on(sstr);
@@ -4133,7 +4127,6 @@ Perl_sv_setsv_flags(pTHX_ SV *dstr, register SV* sstr, const I32 flags)
                 SvCUR_set(dstr, cur);
                 SvREADONLY_on(dstr);
                 SvFAKE_on(dstr);
-                /* Relesase a global SV mutex.  */
             }
             else
                 {	/* Passes the swipe test.  */
@@ -4537,7 +4530,6 @@ Perl_sv_force_normal_flags(pTHX_ register SV *const sv, const U32 flags)
 
 #ifdef PERL_OLD_COPY_ON_WRITE
     if (SvREADONLY(sv)) {
-        /* At this point I believe I should acquire a global SV mutex.  */
 	if (SvFAKE(sv)) {
 	    const char * const pvx = SvPVX_const(sv);
 	    const STRLEN len = SvLEN(sv);
@@ -4578,7 +4570,6 @@ Perl_sv_force_normal_flags(pTHX_ register SV *const sv, const U32 flags)
 	}
 	else if (IN_PERL_RUNTIME)
 	    Perl_croak(aTHX_ "%s", PL_no_modify);
-        /* At this point I believe that I can drop the global SV mutex.  */
     }
 #else
     if (SvREADONLY(sv)) {
@@ -5787,8 +5778,6 @@ Perl_sv_clear(pTHX_ register SV *const sv)
 #ifdef PERL_OLD_COPY_ON_WRITE
 	else if (SvPVX_const(sv)) {
             if (SvIsCOW(sv)) {
-                /* I believe I need to grab the global SV mutex here and
-                   then recheck the COW status.  */
                 if (DEBUG_C_TEST) {
                     PerlIO_printf(Perl_debug_log, "Copy on write: clear\n");
                     sv_dump(sv);
@@ -5799,7 +5788,6 @@ Perl_sv_clear(pTHX_ register SV *const sv)
 		    unshare_hek(SvSHARED_HEK_FROM_PV(SvPVX_const(sv)));
 		}
 
-                /* And drop it here.  */
                 SvFAKE_off(sv);
             } else if (SvLEN(sv)) {
                 Safefree(SvPVX_const(sv));