Re: [PATCH v5 3/3] locking/rwsem: Optimize down_read_trylock()

Subject: Re: [PATCH v5 3/3] locking/rwsem: Optimize down_read_trylock()
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date: Fri, 22 Mar 2019 10:08:29 -0700
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Ingo Molnar <mingo@xxxxxxxxxx>, Will Deacon <will.deacon@xxxxxxx>, Thomas Gleixner <tglx@xxxxxxxxxxxxx>, Linux List Kernel Mailing <linux-kernel@xxxxxxxxxxxxxxx>, "linux-alpha@xxxxxxxxxxxxxxx" <linux-alpha@xxxxxxxxxxxxxxx>, "linux-alpha@xxxxxxxxxxxxxxx" <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>, linux-c6x-dev@xxxxxxxxxxxxx, uclinux-h8-devel@xxxxxxxxxxxxxxxxxxxx, linux-hexagon@xxxxxxxxxxxxxxx, linux-ia64@xxxxxxxxxxxxxxx, linux-m68k <linux-m68k@xxxxxxxxxxxxxxx>, linux-mips@xxxxxxxxxxxxxxx, nios2-dev@xxxxxxxxxxxxxxxxxxxxxx, openrisc@xxxxxxxxxxxxxxxxxxxx, linux-parisc@xxxxxxxxxxxxxxx, linuxppc-dev@xxxxxxxxxxxxxxxx, linux-riscv@xxxxxxxxxxxxxxxxxxx, linux-s390@xxxxxxxxxxxxxxx, Linux-sh list <linux-sh@xxxxxxxxxxxxxxx>, sparclinux@xxxxxxxxxxxxxxx, linux-um@xxxxxxxxxxxxxxxxxxx, linux-xtensa@xxxxxxxxxxxxxxxx, linux-arch <linux-arch@xxxxxxxxxxxxxxx>, "the arch/x86 maintainers" <x86@xxxxxxxxxx>, Arnd Bergmann <arnd@xxxxxxxx>, Borislav Petkov <bp@xxxxxxxxx>, "H. Peter Anvin" <hpa@xxxxxxxxx>, Davidlohr Bueso <dave@xxxxxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
In-reply-to: <20190322143008.21313-4-longman@redhat.com>
References: <20190322143008.21313-1-longman@redhat.com> <20190322143008.21313-4-longman@redhat.com>

On Fri, Mar 22, 2019 at 7:30 AM Waiman Long <longman@xxxxxxxxxx> wrote:


Modify __down_read_trylock() to optimize for an unlocked rwsem and make
it generate slightly better code.


Oh, that should teach me to read all patches in the series before
starting to comment on them.

So ignore my comment on #1.

                Linus

References:
- [PATCH v5 0/3] locking/rwsem: Rwsem rearchitecture part 0
  - From: Waiman Long
- [PATCH v5 3/3] locking/rwsem: Optimize down_read_trylock()
  - From: Waiman Long