lkml.org 
[lkml]   [2007]   [Jul]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Subjectremoving flush_tlb_mm as a generic hook ?
From
Date
Hi folks !

While toying around with various MM callbacks, I found out that
flush_tlb_mm() as a generic hook provided by the archs has been mostly
obsoleted by the mmu_gather stuff.

(I'm not talking about archs internally wanting to implement it and use
it as a tlb_flush(), I'm talking about possibly making that optional :-)

I see two remaining users:

- fs/proc/task_mmu.c, which I easily converted to use the mmu_gather
(I'll send a patch if people agree it's worth doing)

- kernel/fork.c uses it to flush the "old" mm. That's the "meat".

I wonder if it's worth pursuing, that is converting copy_page_range to
use an mmu_gather on the source instead of using flush_tlb_mm. It might
allow some archs that can't just "flush all" easily but have to go
through every PTE individually to improve things a bit on fork, and it
allow them to remove the flush_tlb_mm() logic.

There is one reason why it's not a trivial conversion though, is that
copy_page_range() calls copy_hugetlb_page_range() for huge pages, and
I'm not sure about mixing up the hugetlb stuff with the mmu_gather
stuff, I need to do a bit more code auditing to figure out whether
that's an ok thing to do.

Nothing very urgent or important, it's just that one less hook seems
like a good idea ;-)

Cheers,
Ben.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-07-09 05:51    [W:0.045 / U:0.540 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site