Date: Thu, 30 Jan 2020 20:05:31 -0800 From: Cy Schubert <Cy.Schubert@cschubert.com> To: Jeff Roberson <jeff@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r357314 - in head/sys: conf kern sys vm Message-ID: <202001310405.00V45VZn014071@slippy.cwsent.com> In-Reply-To: <202001310049.00V0np1a077223@repo.freebsd.org> References: <202001310049.00V0np1a077223@repo.freebsd.org>
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In message <202001310049.00V0np1a077223@repo.freebsd.org>, Jeff Roberson writes : > Author: jeff > Date: Fri Jan 31 00:49:51 2020 > New Revision: 357314 > URL: https://svnweb.freebsd.org/changeset/base/357314 > > Log: > Implement a safe memory reclamation feature that is tightly coupled with UM > A. > > This is in the same family of algorithms as Epoch/QSBR/RCU/PARSEC but is > a unique algorithm. This has 3x the performance of epoch in a write heavy > workload with less than half of the read side cost. The memory overhead > is significantly lessened by limiting the free-to-use latency. A synthetic > test uses 1/20th of the memory vs Epoch. There is significant further > discussion in the comments and code review. > > This code should be considered experimental. I will write a man page after > it has settled. After further validation the VM will begin using this > feature to permit lockless page lookups. > > Both markj and cperciva tested on arm64 at large core counts to verify > fences on weaker ordering architectures. I will commit a stress testing > tool in a follow-up. > > Reviewed by: mmacy, markj, rlibby, hselasky > Discussed with: sbahara > Differential Revision: https://reviews.freebsd.org/D22586 > > Added: > head/sys/kern/subr_smr.c (contents, props changed) > head/sys/sys/_smr.h (contents, props changed) > head/sys/sys/smr.h (contents, props changed) > Modified: > head/sys/conf/files > head/sys/vm/uma.h > head/sys/vm/uma_core.c > head/sys/vm/uma_int.h > Thank you for all your hard work Jeff. -- Cheers, Cy Schubert <Cy.Schubert@cschubert.com> FreeBSD UNIX: <cy@FreeBSD.org> Web: http://www.FreeBSD.org The need of the many outweighs the greed of the few.
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