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SubjectRe: [PATCH] net: deinline netif_tx_stop_all_queues(), remove WARN_ON in netif_tx_stop_queue()
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From: Denys Vlasenko <dvlasenk@redhat.com>
Date: Mon, 11 May 2015 21:17:53 +0200

> These functions compile to 60 bytes of machine code each.
> With this .config: http://busybox.net/~vda/kernel_config
> there are 617 calls of netif_tx_stop_queue()
> and 49 calls of netif_tx_stop_all_queues() in vmlinux.
>
> To fix this, remove WARN_ON in netif_tx_stop_queue()
> as suggested by davem, and deinline netif_tx_stop_all_queues().
>
> Change in code size is about 20k:
>
> text data bss dec hex filename
> 82426986 22255416 20627456 125309858 77813a2 vmlinux.before
> 82406248 22255416 20627456 125289120 777c2a0 vmlinux
>
> gcc-4.7.2 still creates deinlined version of netif_tx_stop_queue
> sometimes:
>
> $ nm --size-sort vmlinux | grep netif_tx_stop_queue | wc -l
> 190
>
> ffffffff81b558a8 <netif_tx_stop_queue>:
> ffffffff81b558a8: 55 push %rbp
> ffffffff81b558a9: 48 89 e5 mov %rsp,%rbp
> ffffffff81b558ac: f0 80 8f e0 01 00 00 lock orb $0x1,0x1e0(%rdi)
> ffffffff81b558b3: 01
> ffffffff81b558b4: 5d pop %rbp
> ffffffff81b558b5: c3 retq
>
> This needs additional fixing.
>
> Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

Applied, thank you.


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