From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 23 Jun 2013 15:17:56 +0000 (-0700)
Subject: mlx4: allow order-0 memory allocations in RX path
X-Git-Tag: v3.11-rc1~64^2~150
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=51151a16a60f0a886a0b1e4a0697001198af50c4;p=pandora-kernel.git

mlx4: allow order-0 memory allocations in RX path

Signed-off-by: Eric Dumazet <edumazet@google.com>

mlx4 exclusively uses order-2 allocations in RX path, which are
likely to fail under memory pressure.

We therefore drop frames more than needed.

This patch tries order-3, order-2, order-1 and finally order-0
allocations to keep good performance, yet allow allocations if/when
memory gets fragmented.

By using larger pages, and avoiding unnecessary get_page()/put_page()
on compound pages, this patch improves performance as well, lowering
false sharing on struct page.

Also use GFP_KERNEL allocations in initialization path, as allocating 12
MB (390 order-3 pages) can easily fail with GFP_ATOMIC.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Amir Vadai <amirv@mellanox.com>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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