[pypy-svn] r79916 - pypy/branch/gc-debug/pypy/rpython/memory/gc

[arigo at codespeak.net]

Author: arigo
Date: Thu Dec  9 11:43:19 2010
New Revision: 79916

Modified:
   pypy/branch/gc-debug/pypy/rpython/memory/gc/minimark.py
Log:
Allow PYPY_GC_NURSERY to be set to any value, like 100 or 10K.  If it is
less than the minimum nursery size it will simply bump forward the current
nursery pointer after every minor collection, so that only the specified
number of bytes is left.


Modified: pypy/branch/gc-debug/pypy/rpython/memory/gc/minimark.py
==============================================================================
--- pypy/branch/gc-debug/pypy/rpython/memory/gc/minimark.py	(original)
+++ pypy/branch/gc-debug/pypy/rpython/memory/gc/minimark.py	Thu Dec  9 11:43:19 2010
@@ -3,9 +3,8 @@
 Environment variables can be used to fine-tune the following parameters:
     
  PYPY_GC_NURSERY        The nursery size.  Defaults to half the size of
-                        the L2 cache.  Try values like '1.2MB'.  Minimum
-                        is about 64KB.   Use 1 to force every malloc to
-                        do a minor collection for debugging.
+                        the L2 cache.  Try values like '1.2MB'.  Small values
+                        (like 1 or 1KB) are useful for debugging.
 
  PYPY_GC_MAJOR_COLLECT  Major collection memory factor.  Default is '1.82',
                         which means trigger a major collection when the
@@ -230,7 +229,7 @@
         self.nursery      = NULL
         self.nursery_free = NULL
         self.nursery_top  = NULL
-        self.debug_always_do_minor_collect = False
+        self.debug_tiny_nursery = -1
         self.debug_rotating_nurseries = None
         #
         # The ArenaCollection() handles the nonmovable objects allocation.
@@ -299,15 +298,20 @@
             # From there on, the GC is fully initialized and the code
             # below can use it
             newsize = env.read_from_env('PYPY_GC_NURSERY')
-            # PYPY_GC_NURSERY=1 forces a minor collect for every malloc.
-            # Useful to debug external factors, like trackgcroot or the
-            # handling of the write barrier.
-            self.debug_always_do_minor_collect = newsize == 1
+            # PYPY_GC_NURSERY=smallvalue means that minor collects occur
+            # very frequently; the extreme case is PYPY_GC_NURSERY=1, which
+            # forces a minor collect for every malloc.  Useful to debug
+            # external factors, like trackgcroot or the handling of the write
+            # barrier.  Implemented by still using 'minsize' for the nursery
+            # size (needed to handle e.g. mallocs of 8249 words) but hacking
+            # at the current nursery position in collect_and_reserve().
             if newsize <= 0:
                 newsize = env.estimate_best_nursery_size()
                 if newsize <= 0:
                     newsize = defaultsize
-            newsize = max(newsize, minsize)
+            if newsize < minsize:
+                self.debug_tiny_nursery = newsize & ~(WORD-1)
+                newsize = minsize
             #
             major_coll = env.read_float_from_env('PYPY_GC_MAJOR_COLLECT')
             if major_coll > 1.0:
@@ -561,8 +565,9 @@
         self.nursery_free = result + totalsize
         ll_assert(self.nursery_free <= self.nursery_top, "nursery overflow")
         #
-        if self.debug_always_do_minor_collect:
-            self.nursery_free = self.nursery_top
+        if self.debug_tiny_nursery >= 0:   # for debugging
+            if self.nursery_top - self.nursery_free > self.debug_tiny_nursery:
+                self.nursery_free = self.nursery_top - self.debug_tiny_nursery
         #
         return result
     collect_and_reserve._dont_inline_ = True