Re: Fw: [PATCH] ia64: race flushing icache in do_no_page path

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Rohit Seth wrote:
-----Original Message-----
From: Hugh Dickins [mailto:[email protected]] Sent: Friday, April 27, 2007 10:20 PM
To: Nick Piggin
Cc: [email protected]; Mike Stroyan; Andrew Morton; Luck, Tony;
[email protected]; [email protected]
Subject: Re: Fw: [PATCH] ia64: race flushing icache in do_no_page path

On Sat, 28 Apr 2007, Nick Piggin wrote:

OIC, you need a virtual address to evict the icache, so you can't flush at flush_dcache time? Or does ia64 have an instruction to flush the whole icache? (it would be worth testing, to see how much performance suffers).


IIRC, there is a PAL call to flush the whole cache (but that is quite a
heavy call).  Though you really don't need to be doing this.


I'm puzzled by that remark: the ia64 flush_icache_range always has a virtual address, it uses the kernel virtual address; it takes no interest in whether there's a user virtual address.


Caches on Itanium are physical.  So, it doesn't matter what virtual address
you use to flush a cache line, cache line containing specific physical
memory will be flushed.

Really? I was under the vague impression that L1 i/d caches were virtual
and required this flushing... but I guess so long as the ISA says that
fc/fc.i flushes all caches corresponding to the physical address of the
provided virtual address, then that's what matters.

For the cases where you have virtual caches,
update_mmu_cache is the API to use.

But it happens after the pte is installed.

--
SUSE Labs, Novell Inc.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux