Split GENCGC_PAGE_BYTES in 3 constants

[sbcl.git] / src / compiler / x86 / backend-parms.lisp

diff --git a/src/compiler/x86/backend-parms.lisp b/src/compiler/x86/backend-parms.lisp
index 3f8cf62..5f1e90b 100644 (file)
--- a/src/compiler/x86/backend-parms.lisp
+++ b/src/compiler/x86/backend-parms.lisp
@@ -45,6 +45,15 @@
 ;;;
 ;;;   would be: (setf *backend-page-bytes* 65536)
 
-;;; The size in bytes of the GENCGC pages. Should be a multiple of the
-;;; architecture code size.
-(def!constant gencgc-page-bytes *backend-page-bytes*)
+;;; The size in bytes of GENCGC cards, i.e. the granularity at which
+;;; writes to old generations are logged.  With mprotect-based write
+;;; barriers, this must be a multiple of the OS page size.
+(def!constant gencgc-card-bytes *backend-page-bytes*)
+;;; The minimum size of new allocation regions.  While it doesn't
+;;; currently make a lot of sense to have a card size lower than
+;;; the alloc granularity, it will, once we are smarter about finding
+;;; the start of objects.
+(def!constant gencgc-alloc-granularity *backend-page-bytes*)
+;;; The minimum size at which we release address ranges to the OS.
+;;; This must be a multiple of the OS page size.
+(def!constant gencgc-release-granularity *backend-page-bytes*)