From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: removing flush_tlb_mm as a generic hook ? From: Benjamin Herrenschmidt Content-Type: text/plain Date: Mon, 09 Jul 2007 13:47:54 +1000 Message-Id: <1183952874.3388.349.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org Cc: Linux Kernel list List-ID: 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, 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