In perl.git, the branch smoke-me/nicholas/abolish-STRANGE_MALLOC has been updated
<http://perl5.git.perl.org/perl.git/commitdiff/b9cf7e8932843f09df57a0cbaeececc637d8f34c?hp=c5e13bf5ce9484aa5cbdcc8102718ee15d41c091> - Log ----------------------------------------------------------------- commit b9cf7e8932843f09df57a0cbaeececc637d8f34c Author: Nicholas Clark <[email protected]> Date: Wed Feb 20 21:38:33 2013 +0100 Abolish STRANGE_MALLOC. Now all malloc()s are considered strange :-) STRANGE_MALLOC was added in 5.002 beta 1 (4633a7c4bad06b47) as part of an work around for typical mallocs, which had a bad interaction with perl's allocation needs. Specifically, repeatedly extending an array and then creating SV heads (such as when reading lines of a file into an array) could end up with each reallocation for the array being unable to extend in place, needing a fresh chunk of memory, and the released memory not being suitable for use as more SV heads, so sitting unused. The solution was for perl to recycle the old array body as SV heads, instead of returning it to the system, passing the memory from the the AV code to the SV code using offer_nice_chunk(), PL_nice_chunk and PL_nice_chunk_size. STRANGE_MALLOC was actually a signal that the malloc() didn't need protecting from itself, and to disable the work around. offer_nice_chunk(), PL_nice_chunk and PL_nice_chunk_size were removed by commit 9a87bd09eea1d037 in Nov 2010, without any ill effects, hence the code used when STRANGE_MALLOC was *not* defined is essentially doing extra work for no benefits. From the lack of problems reported, one can assume that in the intervening 15 years malloc technology has got significantly improved, and it is probably better to be honest with it, rather than trying to second guess it. Hence remove all the non-STRANGE_MALLOC code, and leave everyone using the much simpler code. See also http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2005-11/msg00495.html http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2013-01/msg00126.html ----------------------------------------------------------------------- Summary of changes: av.c | 21 --------------------- hv.c | 28 ---------------------------- 2 files changed, 0 insertions(+), 49 deletions(-) diff --git a/av.c b/av.c index 3041cd2..44b5fbc 100644 --- a/av.c +++ b/av.c @@ -119,10 +119,6 @@ Perl_av_extend_guts(pTHX_ AV *av, I32 key, SSize_t *maxp, SV ***allocp, #endif if (*allocp) { -#if !defined(STRANGE_MALLOC) && !defined(MYMALLOC) - MEM_SIZE bytes; - IV itmp; -#endif #ifdef Perl_safesysmalloc_size /* Whilst it would be quite possible to move this logic around @@ -147,24 +143,7 @@ Perl_av_extend_guts(pTHX_ AV *av, I32 key, SSize_t *maxp, SV ***allocp, newmax = key + *maxp / 5; resize: MEM_WRAP_CHECK_1(newmax+1, SV*, oom_array_extend); -#if defined(STRANGE_MALLOC) || defined(MYMALLOC) Renew(*allocp,newmax+1, SV*); -#else - bytes = (newmax + 1) * sizeof(const SV *); -#define MALLOC_OVERHEAD 16 - itmp = MALLOC_OVERHEAD; - while ((MEM_SIZE)(itmp - MALLOC_OVERHEAD) < bytes) - itmp += itmp; - itmp -= MALLOC_OVERHEAD; - itmp /= sizeof(const SV *); - assert(itmp > newmax); - newmax = itmp - 1; - assert(newmax >= *maxp); - Newx(ary, newmax+1, SV*); - Copy(*allocp, ary, *maxp+1, SV*); - Safefree(*allocp); - *allocp = ary; -#endif #ifdef Perl_safesysmalloc_size resized: #endif diff --git a/hv.c b/hv.c index 5f7ae85..0879fe4 100644 --- a/hv.c +++ b/hv.c @@ -1109,7 +1109,6 @@ S_hsplit(pTHX_ HV *hv) } PL_nomemok = TRUE; -#if defined(STRANGE_MALLOC) || defined(MYMALLOC) Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize) + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char); if (!a) { @@ -1119,19 +1118,6 @@ S_hsplit(pTHX_ HV *hv) if (SvOOK(hv)) { Move(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux); } -#else - Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize) - + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char); - if (!a) { - PL_nomemok = FALSE; - return; - } - Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char); - if (SvOOK(hv)) { - Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux); - } - Safefree(HvARRAY(hv)); -#endif PL_nomemok = FALSE; Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/ @@ -1191,7 +1177,6 @@ Perl_hv_ksplit(pTHX_ HV *hv, IV newmax) a = (char *) HvARRAY(hv); if (a) { PL_nomemok = TRUE; -#if defined(STRANGE_MALLOC) || defined(MYMALLOC) Renew(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize) + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char); if (!a) { @@ -1201,19 +1186,6 @@ Perl_hv_ksplit(pTHX_ HV *hv, IV newmax) if (SvOOK(hv)) { Copy(&a[oldsize * sizeof(HE*)], &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux); } -#else - Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(newsize) - + (SvOOK(hv) ? sizeof(struct xpvhv_aux) : 0), char); - if (!a) { - PL_nomemok = FALSE; - return; - } - Copy(HvARRAY(hv), a, oldsize * sizeof(HE*), char); - if (SvOOK(hv)) { - Copy(HvAUX(hv), &a[newsize * sizeof(HE*)], 1, struct xpvhv_aux); - } - Safefree(HvARRAY(hv)); -#endif PL_nomemok = FALSE; Zero(&a[oldsize * sizeof(HE*)], (newsize-oldsize) * sizeof(HE*), char); /* zero 2nd half*/ } -- Perl5 Master Repository
