More conservative defaults in GENCGC

[sbcl.git] / src / compiler / x86-64 / backend-parms.lisp

diff --git a/src/compiler/x86-64/backend-parms.lisp b/src/compiler/x86-64/backend-parms.lisp
index a1802f5..33ffb6e 100644 (file)
--- a/src/compiler/x86-64/backend-parms.lisp
+++ b/src/compiler/x86-64/backend-parms.lisp
@@ -17,7 +17,7 @@
 \f
 ;;;; compiler constants
 
-(def!constant +backend-fasl-file-implementation+ :x86)
+(def!constant +backend-fasl-file-implementation+ :x86-64)
 
 (setf *backend-register-save-penalty* 3)
 
@@ -28,24 +28,22 @@
 ;;; general have our C runtime code running to ask, so instead we set
 ;;; it by hand. -- WHN 2001-04-15
 ;;;
-;;; Though note that POSIX specifies (as far as I can tell)
-;;;
-;;;   sysconf(_SC_PAGE_SIZE);
-;;;
-;;; as a portable way of retrieving this information; a call to this
-;;; could be made in grovel-headers (which, strictly speaking, would
-;;; no longer solely be grovelling headers), though the question of
-;;; how to make this information appear in GENESIS, which is built and
-;;; run from host-1 files (which are made before grovel-headers runs)
-;;; would remain.  -- CSR, 2002-09-01
-(setf *backend-page-size* 4096)
-;;; comment from CMU CL:
-;;;
-;;;   in case we ever wanted to do this for Windows NT..
-;;;
-;;;   Windows NT uses a memory system granularity of 64K, which means
-;;;   everything that gets mapped must be a multiple of that. The real
-;;;   page size is 512, but that doesn't do us a whole lot of good.
-;;;   Effectively, the page size is 64K.
-;;;
-;;;   would be: (setf *backend-page-size* 65536)
+;;; Actually any information that we can retrieve C-side would be
+;;; useless in SBCL, since it's possible for otherwise binary
+;;; compatible systems to return different values for getpagesize().
+;;; -- JES, 2007-01-06
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (setf *backend-page-bytes* 32768))
+
+;;; 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 0)
+;;; 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*)