* Re: [ruby-core:99184] [Ruby master Bug#17023] How to prevent String memory to be relocated in ruby-ffi [not found] ` <redmine.journal-86563.20200715200039.5550@ruby-lang.org> @ 2020-07-15 23:35 ` Eric Wong 2020-07-15 23:49 ` [ruby-core:99185] " Aaron Patterson 0 siblings, 1 reply; 3+ messages in thread From: Eric Wong @ 2020-07-15 23:35 UTC (permalink / raw) To: ruby-core; +Cc: unicorn-public tenderlove@ruby-lang.org wrote: > Right, that makes sense. I really need to document this (and > I apologize for not doing so already), but > `rb_gc_register_address` will pin your objects. When you know > you're done with the reference, you can release it with > `rb_gc_unregister_address`. Of course if you don't call the > unregister function, the reference will stay alive forever. Btw, does rb_gc_register_mark_object pin? A quick glance at gc.c tells me it doesn't, and I'll need to revert commit 2a6cb76d5010cb763ef5a2c305728465d15eb7c9 in unicorn: https://yhbt.net/unicorn-public/20181226050857.6413-1-e@80x24.org/ Anyways, it takes me too long to compile Ruby so I'm back to running whatever my distro ships. I haven't been able to test GC.compact at all. > https://bugs.ruby-lang.org/issues/17023#change-86563 ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [ruby-core:99185] [Ruby master Bug#17023] How to prevent String memory to be relocated in ruby-ffi 2020-07-15 23:35 ` [ruby-core:99184] [Ruby master Bug#17023] How to prevent String memory to be relocated in ruby-ffi Eric Wong @ 2020-07-15 23:49 ` Aaron Patterson 2020-07-16 0:04 ` Eric Wong 0 siblings, 1 reply; 3+ messages in thread From: Aaron Patterson @ 2020-07-15 23:49 UTC (permalink / raw) To: Ruby developers; +Cc: unicorn-public > On Jul 15, 2020, at 4:35 PM, Eric Wong <normalperson@yhbt.net> wrote: > > tenderlove@ruby-lang.org wrote: >> Right, that makes sense. I really need to document this (and >> I apologize for not doing so already), but >> `rb_gc_register_address` will pin your objects. When you know >> you're done with the reference, you can release it with >> `rb_gc_unregister_address`. Of course if you don't call the >> unregister function, the reference will stay alive forever. > > Btw, does rb_gc_register_mark_object pin? A quick glance at > gc.c tells me it doesn't, and I'll need to revert commit > 2a6cb76d5010cb763ef5a2c305728465d15eb7c9 in unicorn: > https://yhbt.net/unicorn-public/20181226050857.6413-1-e@80x24.org/ Yes, it does pin. I’m not super proud of this code, but here is where objects passed to rb_gc_register_mark_object get pinned: https://github.com/ruby/ruby/blob/c2a6295ec04a191c689d22254ac1ad5d665e27ad/vm.c#L2307-L2320 I don’t know why the mark object array is an array of arrays (I assume so as not to waste space in the array buffer?). Maybe this could be a more friendly data structure. I created a pinned list in compile.c so that objects allocated and used at compile time don’t move (they become free to move once iseq assembly is finished). It seems that might be a more generally useful thing, but so far I’ve only seen two places that need this feature. ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [ruby-core:99185] [Ruby master Bug#17023] How to prevent String memory to be relocated in ruby-ffi 2020-07-15 23:49 ` [ruby-core:99185] " Aaron Patterson @ 2020-07-16 0:04 ` Eric Wong 0 siblings, 0 replies; 3+ messages in thread From: Eric Wong @ 2020-07-16 0:04 UTC (permalink / raw) To: Aaron Patterson; +Cc: ruby-core, unicorn-public Aaron Patterson <aaron.patterson@gmail.com> wrote: > > On Jul 15, 2020, at 4:35 PM, Eric Wong <normalperson@yhbt.net> wrote: > > Btw, does rb_gc_register_mark_object pin? A quick glance at > > gc.c tells me it doesn't, and I'll need to revert commit > > 2a6cb76d5010cb763ef5a2c305728465d15eb7c9 in unicorn: > > https://yhbt.net/unicorn-public/20181226050857.6413-1-e@80x24.org/ > > Yes, it does pin. I’m not super proud of this code, but here > is where objects passed to rb_gc_register_mark_object get > pinned: > > https://github.com/ruby/ruby/blob/c2a6295ec04a191c689d22254ac1ad5d665e27ad/vm.c#L2307-L2320 Ah, missed that, thanks. So all is well in unicorn (for now). > I don’t know why the mark object array is an array of arrays > (I assume so as not to waste space in the array buffer?). > Maybe this could be a more friendly data structure. It seems so, since rb_ary_push can double the internal buffer. Anyways, ko1 made commit a617afc643e17cea5c1960a60adcd5ffb25fdfe2 r46714 Maybe it can be flattened nowadays and rely on GC.compact to reclaim unused space. /me goes back to hacking in Perl 5... ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-07-16 0:04 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <redmine.issue-17023.20200710175402.5550@ruby-lang.org> [not found] ` <redmine.journal-86563.20200715200039.5550@ruby-lang.org> 2020-07-15 23:35 ` [ruby-core:99184] [Ruby master Bug#17023] How to prevent String memory to be relocated in ruby-ffi Eric Wong 2020-07-15 23:49 ` [ruby-core:99185] " Aaron Patterson 2020-07-16 0:04 ` Eric Wong
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