Re: overly aggressive memory usage by sort.c

[Paul Eggert]

On 06/10/2012 11:30 PM, Jim Meyering wrote:
> Any objection to reverting that and adjusting the comment to match?

Yes, as this would run afoul of bug 10877
<http://bugs.gnu.org/10877>.  Instead,
I suggest following Jeff Janes's advice
and installing the following patch:

>From c498519fcf4e4a2cc93c1ca75d0b263e215fc01a Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Mon, 11 Jun 2012 02:47:05 -0700
Subject: [PATCH] sort: by default, do not exceed 3/4 of physical memory

* src/sort.c (default_sort_size): Do not exceed 3/4 of total memory.
See Jeff Janes's bug report in
<http://lists.gnu.org/archive/html/coreutils/2012-06/msg00018.html>.
---
 src/sort.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/sort.c b/src/sort.c
index 2593a2a..a517f4e 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -1412,10 +1412,13 @@ default_sort_size (void)
   double mem = MAX (avail, total / 8);
   struct rlimit rlimit;
 
-  /* Let SIZE be MEM, but no more than the maximum object size or
-     system resource limits.  Don't bother to check for values like
-     RLIM_INFINITY since in practice they are not much less than SIZE_MAX.  */
+  /* Let SIZE be MEM, but no more than the maximum object size, 3/4 of
+     total memory, or system resource limits.  Don't bother to check
+     for values like RLIM_INFINITY since in practice they are not much
+     less than SIZE_MAX.  */
   size_t size = SIZE_MAX;
+  if (total * 0.75 < size)
+    size = total * 0.75;
   if (getrlimit (RLIMIT_DATA, &rlimit) == 0 && rlimit.rlim_cur < size)
     size = rlimit.rlim_cur;
 #ifdef RLIMIT_AS
-- 
1.7.6.5