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[Bug 1175] Changed - swap readahead sets the page referenced bit



http://distro.conectiva.com.br/bugzilla/show_bug.cgi?id=1175

--- shadow/1175	Wed Jan 31 16:54:08 2001
+++ shadow/1175.tmp.24105	Thu Feb  1 14:46:48 2001
@@ -3,8 +3,8 @@
 +----------------------------------------------------------------------------+
 |        Bug #: 1175                        Product: Linux kernel MM         |
 |       Status: NEW                         Version: 2.4 (stable)            |
-|   Resolution:                            Platform:                         |
-|     Severity: normal                   OS/Version:                         |
+|   Resolution:                            Platform: All                     |
+|     Severity: normal                   OS/Version: Linux                   |
 |     Priority: P2                        Component: linux mm                |
 +----------------------------------------------------------------------------+
 |  Assigned To: linux-mm-bugs@nl.linux.org                                   |
@@ -25,3 +25,19 @@
 used by any process, they get freed before other (probably more useful) pages.
 
 This can be easily fixed using Rik's __find_page_simple().
\ No newline at end of file
+
+------- Additional Comments From riel@conectiva.com.br  2001-02-01 14:46 -------
+swapin readahead also has the potential to evict lots of useful pages from
+memory, this could/should be most evident when running big processes with very
+random access patterns
+
+the solution in this case would be to place (most of) the pages we do readaround
+on on the inactive_dirty list, so they won't put too much pressure on the
+working set but still have a decent chance of being used
+
+for linear access patterns, we can do things differently ... in this case we can
+put the pages we read in on the active list and do drop_behind() on an equal
+number of pages we've already used
+
+FreeBSD's vm/vm_page.c::vm_page_dontneed() could be a useful model for doing
+this ... anybody have opinions on this idea ?
\ No newline at end of file

-
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