From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vineet Gupta Subject: Re: [PATCH 1/2] mm,thp: refactor generic deposit/withdraw routines for wider usage Date: Thu, 11 Feb 2016 16:23:33 +0530 Message-ID: <56BC682D.6070808@synopsys.com> References: <1455182907-15445-1-git-send-email-vgupta@synopsys.com> <1455182907-15445-2-git-send-email-vgupta@synopsys.com> <20160211112223.0acc8237@mschwide> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160211112223.0acc8237@mschwide> Sender: owner-linux-mm@kvack.org To: Martin Schwidefsky Cc: Andrew Morton , "Kirill A. Shutemov" , "Aneesh Kumar K.V" , "David S. Miller" , Alex Thorlton , Gerald Schaefer , linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Andrea Arcangeli List-Id: linux-arch.vger.kernel.org On Thursday 11 February 2016 03:52 PM, Martin Schwidefsky wrote: > On Thu, 11 Feb 2016 14:58:26 +0530 > Vineet Gupta wrote: > >> Generic pgtable_trans_huge_deposit()/pgtable_trans_huge_withdraw() >> assume pgtable_t to be struct page * which is not true for all arches. >> Thus arc, s390, sparch end up with their own copies despite no special >> hardware requirements (unlike powerpc). > > s390 does have a special hardware requirement. pgtable_t is an address > for a 2K block of memory. It is *not* equivalent to a struct page * > which refers to a 4K block of memory. That has been the whole point > to introduce pgtable_t. Actually my reference to hardware requirement was more like powerpc style save a hash value some where etc. Now pgtable_t need not be struct page * even if the actual sizes are same - e.g. in ARC port I kept pgtable_t as pte_t * simply to avoid a few page_address() calls in mm code (you could argue that is was a micro-optimization, anyways..) So given I know nothing about s390 MMU internals, I still think you can switch to the update generic version despite 2K vs. 4K. Agree ? >> It seems massaging the code a bit can make it reusbale. > > Imho the new code for asm-generic looks fine, as long as the override > with __HAVE_ARCH_PGTABLE_DEPOSIT/__HAVE_ARCH_PGTABLE_WITHDRAW continues > to work I do not mind. -- 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