Index: docs/ref/contrib/admin/index.txt
===================================================================
--- docs/ref/contrib/admin/index.txt	(revision 16213)
+++ docs/ref/contrib/admin/index.txt	(working copy)
@@ -649,6 +649,15 @@
               The ``FieldListFilter`` API is currently considered internal
               and prone to refactoring.
 
+.. attribute:: ModelAdmin.list_max_show_all
+
+    .. versionadded:: 1.4
+
+    Set ``list_max_show_all`` to control how many items can appear on a "Show
+    all" admin change list page. The admin will display a "Show all" link on the
+    change list only if the total result count is less than or equal to this
+    setting. By default, this is set to ``200``.
+
 .. attribute:: ModelAdmin.list_per_page
 
     Set ``list_per_page`` to control how many items appear on each paginated
Index: django/contrib/admin/validation.py
===================================================================
--- django/contrib/admin/validation.py	(revision 16213)
+++ django/contrib/admin/validation.py	(working copy)
@@ -97,6 +97,11 @@
     if hasattr(cls, 'list_per_page') and not isinstance(cls.list_per_page, int):
         raise ImproperlyConfigured("'%s.list_per_page' should be a integer."
                 % cls.__name__)
+    
+    # list_max_show_all
+    if hasattr(cls, 'list_max_show_all') and not isinstance(cls.list_max_show_all, int):
+        raise ImproperlyConfigured("'%s.list_max_show_all' should be an integer."
+                % cls.__name__)
 
     # list_editable
     if hasattr(cls, 'list_editable') and cls.list_editable:
Index: django/contrib/admin/options.py
===================================================================
--- django/contrib/admin/options.py	(revision 16213)
+++ django/contrib/admin/options.py	(working copy)
@@ -268,6 +268,7 @@
     list_filter = ()
     list_select_related = False
     list_per_page = 100
+    list_max_show_all = 200
     list_editable = ()
     search_fields = ()
     date_hierarchy = None
@@ -1064,7 +1065,7 @@
         try:
             cl = ChangeList(request, self.model, list_display, self.list_display_links,
                 self.list_filter, self.date_hierarchy, self.search_fields,
-                self.list_select_related, self.list_per_page, self.list_editable, self)
+                self.list_select_related, self.list_per_page, self.list_max_show_all, self.list_editable, self)
         except IncorrectLookupParameters:
             # Wacky lookup parameters were given, so redirect to the main
             # changelist page, without parameters, and pass an 'invalid=1'
Index: django/contrib/admin/views/main.py
===================================================================
--- django/contrib/admin/views/main.py	(revision 16213)
+++ django/contrib/admin/views/main.py	(working copy)
@@ -11,10 +11,6 @@
 from django.contrib.admin.options import IncorrectLookupParameters
 from django.contrib.admin.util import quote, get_fields_from_path
 
-# The system will display a "Show all" link on the change list only if the
-# total result count is less than or equal to this setting.
-MAX_SHOW_ALL_ALLOWED = 200
-
 # Changelist settings
 ALL_VAR = 'all'
 ORDER_VAR = 'o'
@@ -43,7 +39,7 @@
 class ChangeList(object):
     def __init__(self, request, model, list_display, list_display_links,
             list_filter, date_hierarchy, search_fields, list_select_related,
-            list_per_page, list_editable, model_admin):
+            list_per_page, list_max_show_all, list_editable, model_admin):
         self.model = model
         self.opts = model._meta
         self.lookup_opts = self.opts
@@ -55,6 +51,7 @@
         self.search_fields = search_fields
         self.list_select_related = list_select_related
         self.list_per_page = list_per_page
+        self.list_max_show_all = list_max_show_all
         self.model_admin = model_admin
 
         # Get search parameters from the query string.
@@ -144,7 +141,7 @@
         else:
             full_result_count = self.root_query_set.count()
 
-        can_show_all = result_count <= MAX_SHOW_ALL_ALLOWED
+        can_show_all = result_count <= self.list_max_show_all
         multi_page = result_count > self.list_per_page
 
         # Get the list of objects to display on this page.
Index: tests/regressiontests/admin_filters/tests.py
===================================================================
--- tests/regressiontests/admin_filters/tests.py	(revision 16213)
+++ tests/regressiontests/admin_filters/tests.py	(working copy)
@@ -109,7 +109,7 @@
     def get_changelist(self, request, model, modeladmin):
         return ChangeList(request, model, modeladmin.list_display, modeladmin.list_display_links,
             modeladmin.list_filter, modeladmin.date_hierarchy, modeladmin.search_fields,
-            modeladmin.list_select_related, modeladmin.list_per_page, modeladmin.list_editable, modeladmin)
+            modeladmin.list_select_related, modeladmin.list_per_page, modeladmin.list_max_show_all, modeladmin.list_editable, modeladmin)
 
     def test_datefieldlistfilter(self):
         modeladmin = BookAdmin(Book, site)
Index: tests/regressiontests/admin_changelist/tests.py
===================================================================
--- tests/regressiontests/admin_changelist/tests.py	(revision 16213)
+++ tests/regressiontests/admin_changelist/tests.py	(working copy)
@@ -1,6 +1,6 @@
 from django.contrib import admin
 from django.contrib.admin.options import IncorrectLookupParameters
-from django.contrib.admin.views.main import ChangeList, SEARCH_VAR
+from django.contrib.admin.views.main import ChangeList, SEARCH_VAR, ALL_VAR
 from django.core.paginator import Paginator
 from django.template import Context, Template
 from django.test import TransactionTestCase
@@ -18,7 +18,7 @@
         m = ChildAdmin(Child, admin.site)
         cl = ChangeList(MockRequest(), Child, m.list_display, m.list_display_links,
                 m.list_filter, m.date_hierarchy, m.search_fields,
-                m.list_select_related, m.list_per_page, m.list_editable, m)
+                m.list_select_related, m.list_per_page, m.list_max_show_all, m.list_editable, m)
         self.assertEqual(cl.query_set.query.select_related, {'parent': {'name': {}}})
 
     def test_result_list_empty_changelist_value(self):
@@ -31,7 +31,7 @@
         m = ChildAdmin(Child, admin.site)
         cl = ChangeList(request, Child, m.list_display, m.list_display_links,
                 m.list_filter, m.date_hierarchy, m.search_fields,
-                m.list_select_related, m.list_per_page, m.list_editable, m)
+                m.list_select_related, m.list_per_page, m.list_max_show_all, m.list_editable, m)
         cl.formset = None
         template = Template('{% load admin_list %}{% spaceless %}{% result_list cl %}{% endspaceless %}')
         context = Context({'cl': cl})
@@ -52,7 +52,7 @@
         m = ChildAdmin(Child, admin.site)
         cl = ChangeList(request, Child, m.list_display, m.list_display_links,
                 m.list_filter, m.date_hierarchy, m.search_fields,
-                m.list_select_related, m.list_per_page, m.list_editable, m)
+                m.list_select_related, m.list_per_page, m.list_max_show_all, m.list_editable, m)
         cl.formset = None
         template = Template('{% load admin_list %}{% spaceless %}{% result_list cl %}{% endspaceless %}')
         context = Context({'cl': cl})
@@ -81,7 +81,7 @@
         m.list_editable = ['name']
         cl = ChangeList(request, Child, m.list_display, m.list_display_links,
                 m.list_filter, m.date_hierarchy, m.search_fields,
-                m.list_select_related, m.list_per_page, m.list_editable, m)
+                m.list_select_related, m.list_per_page, m.list_max_show_all, m.list_editable, m)
         FormSet = m.get_changelist_formset(request)
         cl.formset = FormSet(queryset=cl.result_list)
         template = Template('{% load admin_list %}{% spaceless %}{% result_list cl %}{% endspaceless %}')
@@ -115,7 +115,7 @@
         self.assertRaises(IncorrectLookupParameters, lambda: \
             ChangeList(request, Child, m.list_display, m.list_display_links,
                     m.list_filter, m.date_hierarchy, m.search_fields,
-                    m.list_select_related, m.list_per_page, m.list_editable, m))
+                    m.list_select_related, m.list_per_page, m.list_max_show_all, m.list_editable, m))
 
     def test_custom_paginator(self):
         new_parent = Parent.objects.create(name='parent')
@@ -131,7 +131,7 @@
 
         cl = ChangeList(request, Child, m.list_display, m.list_display_links,
                 m.list_filter, m.date_hierarchy, m.search_fields,
-                m.list_select_related, m.list_per_page, m.list_editable, m)
+                m.list_select_related, m.list_per_page, m.list_max_show_all, m.list_editable, m)
 
         cl.get_results(request)
         self.assertIsInstance(cl.paginator, CustomPaginator)
@@ -153,7 +153,7 @@
         cl = ChangeList(request, Band, m.list_display,
                 m.list_display_links, m.list_filter, m.date_hierarchy,
                 m.search_fields, m.list_select_related, m.list_per_page,
-                m.list_editable, m)
+                m.list_max_show_all, m.list_editable, m)
 
         cl.get_results(request)
 
@@ -176,7 +176,7 @@
         cl = ChangeList(request, Group, m.list_display,
                 m.list_display_links, m.list_filter, m.date_hierarchy,
                 m.search_fields, m.list_select_related, m.list_per_page,
-                m.list_editable, m)
+                m.list_max_show_all, m.list_editable, m)
 
         cl.get_results(request)
 
@@ -200,7 +200,7 @@
         cl = ChangeList(request, Quartet, m.list_display,
                 m.list_display_links, m.list_filter, m.date_hierarchy,
                 m.search_fields, m.list_select_related, m.list_per_page,
-                m.list_editable, m)
+                m.list_max_show_all, m.list_editable, m)
 
         cl.get_results(request)
 
@@ -224,7 +224,7 @@
         cl = ChangeList(request, ChordsBand, m.list_display,
                 m.list_display_links, m.list_filter, m.date_hierarchy,
                 m.search_fields, m.list_select_related, m.list_per_page,
-                m.list_editable, m)
+                m.list_max_show_all, m.list_editable, m)
 
         cl.get_results(request)
 
@@ -247,7 +247,7 @@
         cl = ChangeList(request, Parent, m.list_display, m.list_display_links,
                         m.list_filter, m.date_hierarchy, m.search_fields,
                         m.list_select_related, m.list_per_page,
-                        m.list_editable, m)
+                        m.list_max_show_all, m.list_editable, m)
 
         # Make sure distinct() was called
         self.assertEqual(cl.query_set.count(), 1)
@@ -267,7 +267,7 @@
         cl = ChangeList(request, Parent, m.list_display, m.list_display_links,
                         m.list_filter, m.date_hierarchy, m.search_fields,
                         m.list_select_related, m.list_per_page,
-                        m.list_editable, m)
+                        m.list_max_show_all, m.list_editable, m)
 
         # Make sure distinct() was called
         self.assertEqual(cl.query_set.count(), 1)
@@ -288,7 +288,7 @@
         m = ChildAdmin(Child, admin.site)
         cl = ChangeList(request, Child, m.list_display, m.list_display_links,
                 m.list_filter, m.date_hierarchy, m.search_fields,
-                m.list_select_related, m.list_per_page, m.list_editable, m)
+                m.list_select_related, m.list_per_page, m.list_max_show_all, m.list_editable, m)
         self.assertEqual(cl.query_set.count(), 60)
         self.assertEqual(cl.paginator.count, 60)
         self.assertEqual(cl.paginator.page_range, [1, 2, 3, 4, 5, 6])
@@ -297,12 +297,39 @@
         m = FilteredChildAdmin(Child, admin.site)
         cl = ChangeList(request, Child, m.list_display, m.list_display_links,
                 m.list_filter, m.date_hierarchy, m.search_fields,
-                m.list_select_related, m.list_per_page, m.list_editable, m)
+                m.list_select_related, m.list_per_page, m.list_max_show_all, m.list_editable, m)
         self.assertEqual(cl.query_set.count(), 30)
         self.assertEqual(cl.paginator.count, 30)
         self.assertEqual(cl.paginator.page_range, [1, 2, 3])
+    
+    def test_show_all(self):
+        parent = Parent.objects.create(name='anything')
+        for i in range(30):
+            Child.objects.create(name='name %s' % i, parent=parent)
+            Child.objects.create(name='filtered %s' % i, parent=parent)
 
+        request = MockRequest()
+        # Add "show all" parameter to request
+        request.GET[ALL_VAR] = []
+        
+        # Test valid "show all" request (number of total objects is under max)
+        m = ChildAdmin(Child, admin.site)
+        # 200 is the max we'll pass to ChangeList
+        cl = ChangeList(request, Child, m.list_display, m.list_display_links,
+                m.list_filter, m.date_hierarchy, m.search_fields,
+                m.list_select_related, m.list_per_page, 200, m.list_editable, m)
+        cl.get_results(request)
+        self.assertEqual(len(cl.result_list), 60)
+        
+        # Test invalid "show all" request (number of total objects over max) raises exception
+        m = ChildAdmin(Child, admin.site)
+        # 30 is the max we'll pass to ChangeList for this test
+        with self.assertRaises(IncorrectLookupParameters):
+            cl = ChangeList(request, Child, m.list_display, m.list_display_links,
+                    m.list_filter, m.date_hierarchy, m.search_fields,
+                    m.list_select_related, m.list_per_page, 30, m.list_editable, m)
 
+
 class ParentAdmin(admin.ModelAdmin):
     list_filter = ['child__name']
     search_fields = ['child__name']
Index: tests/regressiontests/modeladmin/tests.py
===================================================================
--- tests/regressiontests/modeladmin/tests.py	(revision 16213)
+++ tests/regressiontests/modeladmin/tests.py	(working copy)
@@ -932,7 +932,25 @@
             list_per_page = 100
 
         validate(ValidationTestModelAdmin, ValidationTestModel)
+    
+    def test_max_show_all_allowed_validation(self):
 
+        class ValidationTestModelAdmin(ModelAdmin):
+            list_max_show_all = 'hello'
+
+        self.assertRaisesRegexp(
+            ImproperlyConfigured,
+            "'ValidationTestModelAdmin.list_max_show_all' should be an integer.",
+            validate,
+            ValidationTestModelAdmin,
+            ValidationTestModel,
+        )
+
+        class ValidationTestModelAdmin(ModelAdmin):
+            list_max_show_all = 200
+
+        validate(ValidationTestModelAdmin, ValidationTestModel)
+
     def test_search_fields_validation(self):
 
         class ValidationTestModelAdmin(ModelAdmin):
