linux-kernel - Re: [PATCH 3/6] x86, pmem: add PMEM API for persistent memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1432901463.4282.25.camel@gmail.com>
Date:	Fri, 29 May 2015 06:11:03 -0600
From:	Ross Zwisler <zwisler@...il.com>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Dan Williams <dan.j.williams@...el.com>,
	linux-nvdimm <linux-nvdimm@...1.01.org>, X86 ML <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linux ACPI <linux-acpi@...r.kernel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 3/6] x86, pmem: add PMEM API for persistent memory

On Thu, 2015-05-28 at 21:19 -0700, H. Peter Anvin wrote:
> On 05/28/2015 05:02 PM, Dan Williams wrote:
> > 
> > Hmm, yes, but I believe Ross (on vacation now) was following the
> > precedent set by commit cd8ddf1a2800 "x86: clflush_page_range needs
> > mfence" whereby the api handles all necessary fencing internally.
> > Shall we introduce something like __unordered_clflush_cache_range()
> > for arch_persistent_flush() to use with the understanding it will 
> > be
> > following up with the wmb() in arch_persistent_sync()?
> > 
> 
> Are we ever going to have arch_persistent_sync() without
> arch_persistent_flush()?
> 
> However, thinking about it, it would be more efficient to do all 
> flushes
> first and then have a single barrier.

Yep, we have arch_persistent_sync() without arch_persistent_flush() in
both our PMEM and ND_BLK write paths.  These use arch_persistent_copy() to get NT stores, so they don't need to manually flush/write-back 
before doing a persistent_sync().
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/