add note about the need for deadlock-free sk_buff allocation Signed-off-by: Ed L. Cashin <[EMAIL PROTECTED]>
diff -uprN a/Documentation/aoe/todo.txt b/Documentation/aoe/todo.txt --- a/Documentation/aoe/todo.txt 1969-12-31 19:00:00.000000000 -0500 +++ b/Documentation/aoe/todo.txt 2005-03-10 12:19:57.000000000 -0500 @@ -0,0 +1,14 @@ +There is a potential for deadlock when allocating a struct sk_buff for +data that needs to be written out to aoe storage. If the data is +being written from a dirty page in order to free that page, and if +there are no other pages available, then deadlock may occur when a +free page is needed for the sk_buff allocation. This situation has +not been observed, but it would be nice to eliminate any potential for +deadlock under memory pressure. + +Because ATA over Ethernet is not fragmented by the kernel's IP code, +the destructore member of the struct sk_buff is available to the aoe +driver. By using a mempool for allocating all but the first few +sk_buffs, and by registering a destructor, we should be able to +efficiently allocate sk_buffs without introducing any potential for +deadlock. -- Ed L. Cashin <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
