From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Date: Thu, 14 Feb 2019 11:12:11 +0000 Subject: Re: [PATCH v4 2/3] locking/rwsem: Remove rwsem-spinlock.c & use rwsem-xadd.c for all archs Message-Id: <20190214111211.GL32494@hirez.programming.kicks-ass.net> List-Id: References: <1550095217-12047-1-git-send-email-longman@redhat.com> <1550095217-12047-3-git-send-email-longman@redhat.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Geert Uytterhoeven Cc: "linux-ia64@vger.kernel.org" , Linux-sh list , Will Deacon , Linux Kernel Mailing List , "H. Peter Anvin" , sparclinux , linux-riscv@lists.infradead.org, Christoph Hellwig , Linux-Arch , linux-s390 , Davidlohr Bueso , linux-c6x-dev@linux-c6x.org, "open list:QUALCOMM HEXAGON..." , the arch/x86 maintainers , Ingo Molnar , Waiman Long , "moderated list:H8/300 ARCHITECTURE" , linux-xtensa@linux-xtensa.org, Arnd Bergmann , linux-um@lists.infradead.org, linuxppc-dev On Thu, Feb 14, 2019 at 11:54:47AM +0100, Geert Uytterhoeven wrote: > On Wed, Feb 13, 2019 at 11:01 PM Waiman Long wrote: > > Currently, we have two different implementation of rwsem: > > 1) CONFIG_RWSEM_GENERIC_SPINLOCK (rwsem-spinlock.c) > > 2) CONFIG_RWSEM_XCHGADD_ALGORITHM (rwsem-xadd.c) > > > > As we are going to use a single generic implementation for rwsem-xadd.c > > and no architecture-specific code will be needed, there is no point > > in keeping two different implementations of rwsem. In most cases, the > > performance of rwsem-spinlock.c will be worse. It also doesn't get all > > the performance tuning and optimizations that had been implemented in > > rwsem-xadd.c over the years. > > > > For simplication, we are going to remove rwsem-spinlock.c and make all > > architectures use a single implementation of rwsem - rwsem-xadd.c. > > > > All references to RWSEM_GENERIC_SPINLOCK and RWSEM_XCHGADD_ALGORITHM > > in the code are removed. > > > > Suggested-by: Peter Zijlstra > > Signed-off-by: Waiman Long > > Note that this conflicts with "[PATCH 03/11] kernel/locks: consolidate > RWSEM_GENERIC_* options" > https://lore.kernel.org/lkml/20190213174005.28785-4-hch@lst.de/ *sigh*.. of that never was Cc'ed to locking people :/