From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH mk-II 08/17] asm-generic/tlb: Provide MMU_GATHER_TABLE_FREE Date: Mon, 27 Jan 2020 09:11:34 +0100 Message-ID: <20200127081134.GI14914@hirez.programming.kicks-ass.net> References: <20191211120713.360281197@infradead.org> <20191211122956.112607298@infradead.org> <20191212093205.GU2827@hirez.programming.kicks-ass.net> <20200126155205.GA19169@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200126155205.GA19169@roeck-us.net> Sender: linux-kernel-owner@vger.kernel.org To: Guenter Roeck Cc: Will Deacon , "Aneesh Kumar K.V" , Andrew Morton , Nick Piggin , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yoshinori Sato , Rich Felker , "David S. Miller" , Helge Deller , Geert Uytterhoeven , Paul Burton , Tony Luck , Richard Henderson , Nick Hu , Paul Walmsley List-Id: linux-arch.vger.kernel.org On Sun, Jan 26, 2020 at 07:52:05AM -0800, Guenter Roeck wrote: > On Thu, Dec 12, 2019 at 10:32:05AM +0100, Peter Zijlstra wrote: > > As described in the comment, the correct order for freeing pages is: > > > > 1) unhook page > > 2) TLB invalidate page > > 3) free page > > > > This order equally applies to page directories. > > > > Currently there are two correct options: > > > > - use tlb_remove_page(), when all page directores are full pages and > > there are no futher contraints placed by things like software > > walkers (HAVE_FAST_GUP). > > > > - use MMU_GATHER_RCU_TABLE_FREE and tlb_remove_table() when the > > architecture does not do IPI based TLB invalidate and has > > HAVE_FAST_GUP (or software TLB fill). > > > > This however leaves architectures that don't have page based > > directories but don't need RCU in a bind. For those, provide > > MMU_GATHER_TABLE_FREE, which provides the independent batching for > > directories without the additional RCU freeing. > > > > Signed-off-by: Peter Zijlstra (Intel) > > --- > > Various sparc64 builds (allnoconfig, tinyconfig, as well as builds > with SMP disabled): > > mm/mmu_gather.c: In function '__tlb_remove_table_free': > mm/mmu_gather.c:101:3: error: implicit declaration of function '__tlb_remove_table'; did you mean 'tlb_remove_table'? Thanks; I'll respin these patches against Aneesh' pile and make sure to look into this when I do so. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:40326 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727093AbgA0IMI (ORCPT ); Mon, 27 Jan 2020 03:12:08 -0500 Date: Mon, 27 Jan 2020 09:11:34 +0100 From: Peter Zijlstra Subject: Re: [PATCH mk-II 08/17] asm-generic/tlb: Provide MMU_GATHER_TABLE_FREE Message-ID: <20200127081134.GI14914@hirez.programming.kicks-ass.net> References: <20191211120713.360281197@infradead.org> <20191211122956.112607298@infradead.org> <20191212093205.GU2827@hirez.programming.kicks-ass.net> <20200126155205.GA19169@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200126155205.GA19169@roeck-us.net> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Guenter Roeck Cc: Will Deacon , "Aneesh Kumar K.V" , Andrew Morton , Nick Piggin , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yoshinori Sato , Rich Felker , "David S. Miller" , Helge Deller , Geert Uytterhoeven , Paul Burton , Tony Luck , Richard Henderson , Nick Hu , Paul Walmsley Message-ID: <20200127081134.fWonNLQpEA98v2F-7G0QKhg4QPgyAJlyvbMop7qt9uY@z> On Sun, Jan 26, 2020 at 07:52:05AM -0800, Guenter Roeck wrote: > On Thu, Dec 12, 2019 at 10:32:05AM +0100, Peter Zijlstra wrote: > > As described in the comment, the correct order for freeing pages is: > > > > 1) unhook page > > 2) TLB invalidate page > > 3) free page > > > > This order equally applies to page directories. > > > > Currently there are two correct options: > > > > - use tlb_remove_page(), when all page directores are full pages and > > there are no futher contraints placed by things like software > > walkers (HAVE_FAST_GUP). > > > > - use MMU_GATHER_RCU_TABLE_FREE and tlb_remove_table() when the > > architecture does not do IPI based TLB invalidate and has > > HAVE_FAST_GUP (or software TLB fill). > > > > This however leaves architectures that don't have page based > > directories but don't need RCU in a bind. For those, provide > > MMU_GATHER_TABLE_FREE, which provides the independent batching for > > directories without the additional RCU freeing. > > > > Signed-off-by: Peter Zijlstra (Intel) > > --- > > Various sparc64 builds (allnoconfig, tinyconfig, as well as builds > with SMP disabled): > > mm/mmu_gather.c: In function '__tlb_remove_table_free': > mm/mmu_gather.c:101:3: error: implicit declaration of function '__tlb_remove_table'; did you mean 'tlb_remove_table'? Thanks; I'll respin these patches against Aneesh' pile and make sure to look into this when I do so.