Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)

Arjan van de Ven wrote:

The jne is expected to fail, so we will always continue to 0x13. Now is
this a problem with x86/x86_64?

I'm not saying there is a problem; likely/unlikely do have an effect for
sure, it's just not a "make it free" thing....

On x86 I think the main saving is the icache one. However I guess
gcc would try to align with the branch prediction behaviour for
unknown branches too.

The microoptimisation is that the call avoids the unlikely branch
in kfree. Maybe for x86 this isn't going to matter, but for some
architectures in might.

--
SUSE Labs, Novell Inc.

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• References:
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Jeff Garzik <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Andrew Morton <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Arjan van de Ven <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Steven Rostedt <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Arjan van de Ven <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Steven Rostedt <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Arjan van de Ven <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Arjan van de Ven <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Steven Rostedt <[email protected]>
  • Re: [PATCH] ext3_clear_inode(): avoid kfree(NULL)
    • From: Arjan van de Ven <[email protected]>

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