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| author | ecashin@coraid.com <ecashin@coraid.com> | 2005-04-18 22:00:21 -0700 |
|---|---|---|
| committer | Greg KH <greg@press.kroah.org> | 2005-04-18 22:00:21 -0700 |
| commit | e3b7df65e089f143b9228472b80fb96c495fb634 (patch) | |
| tree | a2366a9a09aaa9063b3b4e41eab747fc0c8b29a5 /Documentation/aoe | |
| parent | d098840e37468fdd0143d8bcfe86bc53627bf96e (diff) | |
| download | lwn-e3b7df65e089f143b9228472b80fb96c495fb634.tar.gz lwn-e3b7df65e089f143b9228472b80fb96c495fb634.zip | |
[PATCH] aoe 9/12: add note about the need for deadlock-free sk_buff allocation
add note about the need for deadlock-free sk_buff allocation
Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation/aoe')
| -rw-r--r-- | Documentation/aoe/todo.txt | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/aoe/todo.txt b/Documentation/aoe/todo.txt new file mode 100644 index 000000000000..7fee1e1165bc --- /dev/null +++ b/Documentation/aoe/todo.txt @@ -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. |