From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 10/28] mm: only allow page table mappings for built-in zsmalloc Date: Wed, 8 Apr 2020 17:36:02 +0200 Message-ID: <20200408153602.GA28081@lst.de> References: <20200408115926.1467567-1-hch@lst.de> <20200408115926.1467567-11-hch@lst.de> <20200408151203.GN20730@hirez.programming.kicks-ass.net> <20200408151519.GQ21484@bombadil.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200408151519.GQ21484@bombadil.infradead.org> Sender: linux-kernel-owner@vger.kernel.org To: Matthew Wilcox Cc: Peter Zijlstra , Randy Dunlap , Christoph Hellwig , Andrew Morton , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , x86@kernel.org, David Airlie , Daniel Vetter , Laura Abbott , Sumit Semwal , Sakari Ailus , Minchan Kim , Nitin Gupta , Robin Murphy , Christophe Leroy , linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org, dri-devel@lists.freedesktop.orgli List-Id: linux-arch.vger.kernel.org On Wed, Apr 08, 2020 at 08:15:19AM -0700, Matthew Wilcox wrote: > > > > config ZSMALLOC_PGTABLE_MAPPING > > > > bool "Use page table mapping to access object in zsmalloc" > > > > - depends on ZSMALLOC > > > > + depends on ZSMALLOC=y > > > > > > It's a bool so this shouldn't matter... not needed. > > > > My mm/Kconfig has: > > > > config ZSMALLOC > > tristate "Memory allocator for compressed pages" > > depends on MMU > > > > which I think means it can be modular, no? > > Randy means that ZSMALLOC_PGTABLE_MAPPING is a bool, so I think hch's patch > is wrong ... if ZSMALLOC is 'm' then ZSMALLOC_PGTABLE_MAPPING would become > 'n' instead of 'y'. In Linus' tree you can select PGTABLE_MAPPING=y with ZSMALLOC=m, and that fits my understanding of the kbuild language. With this patch I can't anymore. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 8 Apr 2020 17:36:02 +0200 From: Christoph Hellwig Subject: Re: [PATCH 10/28] mm: only allow page table mappings for built-in zsmalloc Message-ID: <20200408153602.GA28081@lst.de> References: <20200408115926.1467567-1-hch@lst.de> <20200408115926.1467567-11-hch@lst.de> <20200408151203.GN20730@hirez.programming.kicks-ass.net> <20200408151519.GQ21484@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200408151519.GQ21484@bombadil.infradead.org> Sender: owner-linux-mm@kvack.org To: Matthew Wilcox Cc: Peter Zijlstra , Randy Dunlap , Christoph Hellwig , Andrew Morton , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , x86@kernel.org, David Airlie , Daniel Vetter , Laura Abbott , Sumit Semwal , Sakari Ailus , Minchan Kim , Nitin Gupta , Robin Murphy , Christophe Leroy , linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: Message-ID: <20200408153602.ssArrU4DwjrSObOEElRuY3JTgn7mJKXy73yiAJGZi-g@z> On Wed, Apr 08, 2020 at 08:15:19AM -0700, Matthew Wilcox wrote: > > > > config ZSMALLOC_PGTABLE_MAPPING > > > > bool "Use page table mapping to access object in zsmalloc" > > > > - depends on ZSMALLOC > > > > + depends on ZSMALLOC=y > > > > > > It's a bool so this shouldn't matter... not needed. > > > > My mm/Kconfig has: > > > > config ZSMALLOC > > tristate "Memory allocator for compressed pages" > > depends on MMU > > > > which I think means it can be modular, no? > > Randy means that ZSMALLOC_PGTABLE_MAPPING is a bool, so I think hch's patch > is wrong ... if ZSMALLOC is 'm' then ZSMALLOC_PGTABLE_MAPPING would become > 'n' instead of 'y'. In Linus' tree you can select PGTABLE_MAPPING=y with ZSMALLOC=m, and that fits my understanding of the kbuild language. With this patch I can't anymore.