From: Lars Ingebrigtsen Date: Thu, 16 Sep 2021 15:13:11 +0000 (+0200) Subject: Mention that the garbage collection is convervative X-Git-Tag: emacs-28.0.90~896 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=928c1626732256a234014ed1b9d44853a85bc7f1;p=emacs.git Mention that the garbage collection is convervative * doc/lispref/internals.texi (Garbage Collection): Mention that we're using a conservative gc (bug#42013). --- diff --git a/doc/lispref/internals.texi b/doc/lispref/internals.texi index 0e250d0f59b..d3edd633171 100644 --- a/doc/lispref/internals.texi +++ b/doc/lispref/internals.texi @@ -337,18 +337,22 @@ by the vector allocation code while iterating over the vector blocks. It is quite common to use some storage for a while, then release it by (for example) killing a buffer or deleting the last pointer to an object. Emacs provides a @dfn{garbage collector} to reclaim this -abandoned storage. The garbage collector operates by finding and -marking all Lisp objects that are still accessible to Lisp programs. -To begin with, it assumes all the symbols, their values and associated -function definitions, and any data presently on the stack, are -accessible. Any objects that can be reached indirectly through other -accessible objects are also accessible. +abandoned storage. The garbage collector operates, in essence, by +finding and marking all Lisp objects that are still accessible to Lisp +programs. To begin with, it assumes all the symbols, their values and +associated function definitions, and any data presently on the stack, +are accessible. Any objects that can be reached indirectly through +other accessible objects are also accessible, but this calculation is +done ``conservatively'', so it may slightly overestimate how many +objects that are accessible. When marking is finished, all objects still unmarked are garbage. No matter what the Lisp program or the user does, it is impossible to refer to them, since there is no longer a way to reach them. Their space might as well be reused, since no one will miss them. The second -(sweep) phase of the garbage collector arranges to reuse them. +(sweep) phase of the garbage collector arranges to reuse them. (But +since the marking was done ``conservatively'', not all unused objects +are guaranteed to be garbage-collected by any one sweep.) @c ??? Maybe add something describing weak hash tables here?