Messages in this thread Patch in this message | | | Subject | [patch] 2.4's sys_readahead is borked | From | Robert Love <> | Date | Tue, 03 Feb 2004 19:19:22 -0500 |
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In 2.4, sys_readahead() performs readahead against a maximum of half the number of inactive pages. This is dumb, as it ignores the number of free pages completely. Worse, in certain situations, such as boot, the inactive list can be quite small and the free list quite large, but readahead(2) won't do anything.
The right thing to do is limit sys_readahead() to a maximum of half of the sum of the number of free pages and inactive pages, which is what 2.6 does.
Attached patch is against 2.4.25-pre8. Please apply.
Robert Love
mm/filemap.c | 2 +- 1 files changed, 1 insertion(+), 1 deletion(-)
diff -urN linux-2.4.25-pre8/mm/filemap.c.orig linux-2.4.25-pre8/mm/filemap.c --- linux-2.4.25-pre8/mm/filemap.c.orig 2004-02-03 19:13:33.540115456 -0500 +++ linux-2.4.25-pre8/mm/filemap.c 2004-02-03 19:13:49.468693944 -0500 @@ -1965,7 +1965,7 @@ nr = max; /* And limit it to a sane percentage of the inactive list.. */ - max = nr_inactive_pages / 2; + max = (nr_free_pages() + nr_inactive_pages) / 2; if (nr > max) nr = max; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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