Re: [PATCH] fdtable: Eradicate fdarray overflow.
From: Eric Dumazet
Date: Thu Oct 12 2006 - 01:27:11 EST
Vadim Lobanov a écrit :
diff -Npru old/fs/file.c new/fs/file.c
--- old/fs/file.c 2006-10-10 18:58:21.000000000 -0700
+++ new/fs/file.c 2006-10-11 19:37:23.000000000 -0700
@@ -164,9 +164,8 @@ static struct fdtable * alloc_fdtable(un
* the fdarray into page-sized chunks: starting at a quarter of a page,
* and growing in powers of two from there on.
*/
- nr++;
nr /= (PAGE_SIZE / 4 / sizeof(struct file *));
- nr = roundup_pow_of_two(nr);
+ nr = roundup_pow_of_two(nr + 1);
nr *= (PAGE_SIZE / 4 / sizeof(struct file *));
if (nr > NR_OPEN)
nr = NR_OPEN;
Hi Vadim
I find your PAGE_SIZE/4 minimum allocation quite unjustified.
For architectures with 64K PAGE_SIZE, we endup allocating 16K, for poor tasks
that happen to touch a not so high (>= 64) file descriptor...
I would vote for a fixed size, like 1024
Eric
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