From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 4 Jul 2007 16:38:26 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [BUGFIX][PATCH] DO flush icache before set_pte() on ia64. Message-Id: <20070704163826.d0b7465b.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <468B3EAA.9070905@yahoo.com.au> References: <20070704150504.423f6c54.kamezawa.hiroyu@jp.fujitsu.com> <468B3EAA.9070905@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: "linux-ia64@vger.kernel.org" , LKML , "tony.luck@intel.com" , "linux-mm@kvack.org" , Christoph Lameter , Mike.stroya@hp.com, GOTO , dmosberger@gmail.com, hugh@veritas.com List-ID: On Wed, 04 Jul 2007 16:31:06 +1000 Nick Piggin wrote: > The only thing I noticed when I looked at the code is that some places > may not have flushed icache when they should have? Did you get them all? I think that I added flush_icache_page() to the place where any flush_(i)cache_xxx is not called and lazy_mmu_prot_update was used instead of them. But I want good review, of course. > Minor nitpick: you have one place where you test VM_EXEC before flushing, > but the flush routine itself contains the same test I think? > Ah, yes...in do_anonymous_page(). my mistake. > Regarding the ia64 code -- I'm not an expert so I can't say whether it > is the right thing to do or not. However I still can't work out what it's > rationale for the PG_arch_1 bit is, exactly. Does it assume that > flush_dcache_page sites would only ever be encountered by pages that are > not faulted in? A faulted in page kind of is "special" because it is > guaranteed uptodate, but is the ia64 arch code relying on that? Should it? (I'm sorry if I misses point.) ia64's D-cache is coherent but I-cache and D-cache is not coherent and any invalidation against d-cache will invalidate I-cache. In my understanding : PG_arch_1 is used for showing "there is no inconsistent data on any level of cache". PG_uptodate is used for showing "this page includes the newest data and contents are valid." ...maybe not used for the same purpose. BTW, a page filled by DMA should have PG_arch_1 :( -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org