Re: [PATCH 0 of 4] mm+paravirt+xen: add pte read-modify-write abstraction

[Jeremy Fitzhardinge <jeremy@goop.org>]

Linus Torvalds wrote:
> On Fri, 23 May 2008, Jeremy Fitzhardinge wrote:
>   
>> This series adds the pte_rmw_start() and pte_rmw_commit() operations,
>> which change this sequence to:
>>
>> 	ptent = pte_rmw_start(mm, addr, pte);
>> 	ptent = pte_modify(ptent, newprot);
>> 	/* ... */
>> 	pte_rmw_commit(mm, addr, pte, ptent);
>>     
>
> Can you please rename these.
>
> It's not a general "read-modify-write" operation on the PTE, and this 
> *only* works for changing protection details. In particular, you cannot 
> use pte_rmw_start/commit to change the actual page. So it's very much 
> about just protection bits.
>   

Well, you could use it to update the page and protection bits while 
preserving the AD bits, but I don't think that's very useful.

> It should probably also be called ptep_xyz(), since it takes a pte 
> pointer, not a pte.
>
> So maybe calling it "ptent = ptep_modify_prot_start(..)" ... 
> "ptep_modify_prot_commit(..)" or something.
>   

Yep, sounds fine to me.

    J