> From: Ludovic Courtès <[email protected]> > Is there any chance that you’re using a GC 7.3 pre-release?
Using gc-7.2b-2.fc17.i686 on Linux 3.6.10-2.fc17.i686 #1 SMP > There was a similar report on IRC, and the fix appears to be: It does fix my SEGV > (Note that on 2.0 SMOB mark procedures are unnecessary.) Cool. Let's yank it from the manual. Case closed. Yet... For what it is worth, I decided to get som statistics on how often smob_mark is called from a thread with scm_i_current_thread == NULL vs how often it is called from a thread where it is not null. I wrote the attached patch, and then, using the same little library as in my initial report, I ran (use-modules (smobbug)) ;; Create a SMOB type (handlesmob-init) (for-each (lambda (x) (gc)) (iota 1000)) (gc-smob-mark-report) This returned Count of GC SMOB marks from null thread: 176 Count of GC SMOB marks from current thread: 825 Is that expected that GC is sometimes called from a thread where scm_i_current_thread is null and sometimes called from a thread where scm_i_current_thread is not null? -Mike
From 807b00d91fa3b7016987ecfd6992e7b7e943d1e3 Mon Sep 17 00:00:00 2001 From: Mike Gran <[email protected]> Date: Tue, 5 Feb 2013 08:18:07 -0800 Subject: [PATCH] Add function to debug smob gc * libguile/gc.c (scm_gc_smob_mark_report): new report function * libguile/gc.h: new declaration of scm_gc_smob_mark_report * libguile/smob.c (smob_mark): gather statistics --- libguile/gc.c | 22 ++++++++++++++++++++++ libguile/gc.h | 1 + libguile/smob.c | 8 +++++++- 3 files changed, 30 insertions(+), 1 deletion(-) diff --git a/libguile/gc.c b/libguile/gc.c index 06b5044..d06fa6c 100644 --- a/libguile/gc.c +++ b/libguile/gc.c @@ -77,6 +77,10 @@ extern unsigned long * __libc_ia64_register_backing_store_base; int scm_debug_cell_accesses_p = 0; int scm_expensive_debug_cell_accesses_p = 0; + +extern long scm_mark_from_null; +extern long scm_mark_from_current; + /* Set this to 0 if no additional gc's shall be performed, otherwise set it to * the number of cell accesses after which a gc shall be called. */ @@ -383,6 +387,24 @@ SCM_DEFINE (scm_gc_enable, "gc-enable", 0, 0, 0, } #undef FUNC_NAME +SCM_DEFINE (scm_gc_smob_mark_report, "gc-smob-mark-report", 0, 0, 0, + (), + "Print statistics on gc marking of smobs.") +#define FUNC_NAME s_scm_gc_smob_mark_report +{ + scm_puts ("Count of GC SMOB marks from null thread: ", + scm_current_output_port ()); + scm_display (scm_from_long (scm_mark_from_null), scm_current_output_port ()); + scm_newline (scm_current_output_port ()); + scm_puts ("Count of GC SMOB marks from current thread: ", + scm_current_output_port ()); + scm_display (scm_from_long (scm_mark_from_current), + scm_current_output_port ()); + scm_newline (scm_current_output_port ()); + return SCM_UNSPECIFIED; +} +#undef FUNC_NAME + SCM_DEFINE (scm_gc, "gc", 0, 0, 0, (), diff --git a/libguile/gc.h b/libguile/gc.h index 9f00e01..1120aa8 100644 --- a/libguile/gc.h +++ b/libguile/gc.h @@ -173,6 +173,7 @@ SCM_API SCM scm_set_debug_cell_accesses_x (SCM flag); SCM_API SCM scm_object_address (SCM obj); SCM_API SCM scm_gc_enable (void); +SCM_API SCM scm_gc_smob_mark_report (void); SCM_API SCM scm_gc_disable (void); SCM_API SCM scm_gc_dump (void); SCM_API SCM scm_gc_stats (void); diff --git a/libguile/smob.c b/libguile/smob.c index c2e8f24..cc8b59a 100644 --- a/libguile/smob.c +++ b/libguile/smob.c @@ -52,6 +52,7 @@ long scm_numsmob; scm_smob_descriptor scm_smobs[MAX_SMOB_COUNT]; +long scm_mark_from_null = 0, scm_mark_from_current = 0; void scm_assert_smob_type (scm_t_bits tag, SCM val) @@ -294,6 +295,11 @@ smob_mark (GC_word *addr, struct GC_ms_entry *mark_stack_ptr, register SCM cell; register scm_t_bits tc, smobnum; + if (SCM_I_CURRENT_THREAD == NULL) + scm_mark_from_null ++; + else + scm_mark_from_current ++; + cell = PTR2SCM (addr); if (SCM_TYP7 (cell) != scm_tc7_smob) @@ -318,7 +324,7 @@ smob_mark (GC_word *addr, struct GC_ms_entry *mark_stack_ptr, mark_stack_ptr, mark_stack_limit, NULL); - if (scm_smobs[smobnum].mark) + if (scm_smobs[smobnum].mark && SCM_I_CURRENT_THREAD != NULL) { SCM obj; -- 1.7.11.7
