From: Christoph Hellwig <hch@infradead.org>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Mike Snitzer <msnitzer@redhat.com>,
dm-devel@redhat.com, linux-nvdimm@lists.01.org
Subject: Re: [dm-devel] [patch 4/4] dm-writecache: use new API for flushing
Date: Mon, 21 May 2018 23:39:46 -0700 [thread overview]
Message-ID: <20180522063946.GB8054@infradead.org> (raw)
In-Reply-To: <20180519052635.567438191@debian.vm>
On Sat, May 19, 2018 at 07:25:07AM +0200, Mikulas Patocka wrote:
> Use new API for flushing persistent memory.
The sentence doesnt make much sense. 'A new API', 'A better
abstraction' maybe?
>
> The problem is this:
> * on X86-64, non-temporal stores have the best performance
> * ARM64 doesn't have non-temporal stores, so we must flush cache. We
> should flush cache as late as possible, because it performs better this
> way.
>
> We introduce functions pmem_memcpy, pmem_flush and pmem_commit. To commit
> data persistently, all three functions must be called.
>
> The macro pmem_assign may be used instead of pmem_memcpy. pmem_assign
> (unlike pmem_memcpy) guarantees that 8-byte values are written atomically.
>
> On X86, pmem_memcpy is memcpy_flushcache, pmem_flush is empty and
> pmem_commit is wmb.
>
> On ARM64, pmem_memcpy is memcpy, pmem_flush is arch_wb_cache_pmem and
> pmem_commit is empty.
All these should be provided by the pmem layer, and be properly
documented. And be sorted before adding your new target that uses
them.
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
To: Mikulas Patocka <mpatocka-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Mike Snitzer <msnitzer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org
Subject: Re: [dm-devel] [patch 4/4] dm-writecache: use new API for flushing
Date: Mon, 21 May 2018 23:39:46 -0700 [thread overview]
Message-ID: <20180522063946.GB8054@infradead.org> (raw)
In-Reply-To: <20180519052635.567438191-59tzFEB+POEAvxtiuMwx3w@public.gmane.org>
On Sat, May 19, 2018 at 07:25:07AM +0200, Mikulas Patocka wrote:
> Use new API for flushing persistent memory.
The sentence doesnt make much sense. 'A new API', 'A better
abstraction' maybe?
>
> The problem is this:
> * on X86-64, non-temporal stores have the best performance
> * ARM64 doesn't have non-temporal stores, so we must flush cache. We
> should flush cache as late as possible, because it performs better this
> way.
>
> We introduce functions pmem_memcpy, pmem_flush and pmem_commit. To commit
> data persistently, all three functions must be called.
>
> The macro pmem_assign may be used instead of pmem_memcpy. pmem_assign
> (unlike pmem_memcpy) guarantees that 8-byte values are written atomically.
>
> On X86, pmem_memcpy is memcpy_flushcache, pmem_flush is empty and
> pmem_commit is wmb.
>
> On ARM64, pmem_memcpy is memcpy, pmem_flush is arch_wb_cache_pmem and
> pmem_commit is empty.
All these should be provided by the pmem layer, and be properly
documented. And be sorted before adding your new target that uses
them.
next prev parent reply other threads:[~2018-05-22 6:39 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-19 5:25 [patch 0/4] dm-writecache patches Mikulas Patocka
2018-05-19 5:25 ` [patch 1/4] x86: optimize memcpy_flushcache Mikulas Patocka
2018-05-19 14:21 ` Dan Williams
2018-05-24 18:20 ` [PATCH v2] " Mike Snitzer
2018-06-18 13:23 ` [PATCH v2 RESEND] " Mike Snitzer
2018-06-18 13:23 ` Mike Snitzer
2018-06-21 14:31 ` Ingo Molnar
2018-06-22 1:19 ` Mikulas Patocka
2018-06-22 1:19 ` Mikulas Patocka
2018-06-22 1:30 ` Ingo Molnar
2018-08-08 21:22 ` [PATCH v3 " Mikulas Patocka
2018-09-10 13:18 ` Ingo Molnar
2018-09-11 6:22 ` [tip:x86/asm] x86/asm: Optimize memcpy_flushcache() tip-bot for Mikulas Patocka
2018-05-19 5:25 ` [patch 2/4] swait: export the symbols __prepare_to_swait and __finish_swait Mikulas Patocka
2018-05-22 6:34 ` Christoph Hellwig
2018-05-22 18:52 ` Mike Snitzer
2018-05-23 9:21 ` Peter Zijlstra
2018-05-23 15:10 ` Mike Snitzer
2018-05-23 18:10 ` [PATCH v2] swait: export " Mike Snitzer
2018-05-23 20:38 ` Mikulas Patocka
2018-05-23 21:51 ` Mike Snitzer
2018-05-24 14:10 ` Peter Zijlstra
2018-05-24 15:09 ` Mike Snitzer
2018-05-19 5:25 ` [patch 3/4] dm-writecache Mikulas Patocka
2018-05-22 6:37 ` Christoph Hellwig
2018-05-19 5:25 ` [patch 4/4] dm-writecache: use new API for flushing Mikulas Patocka
2018-05-22 6:39 ` Christoph Hellwig [this message]
2018-05-22 6:39 ` [dm-devel] " Christoph Hellwig
2018-05-22 18:41 ` Mike Snitzer
2018-05-22 18:41 ` Mike Snitzer
2018-05-22 19:00 ` Dan Williams
2018-05-22 19:00 ` Dan Williams
2018-05-22 19:19 ` Mike Snitzer
2018-05-22 19:19 ` Mike Snitzer
2018-05-22 19:27 ` Dan Williams
2018-05-22 19:27 ` Dan Williams
2018-05-22 20:52 ` Mike Snitzer
2018-05-22 20:52 ` Mike Snitzer
2018-05-22 22:53 ` [dm-devel] " Jeff Moyer
2018-05-22 22:53 ` Jeff Moyer
2018-05-23 20:57 ` Mikulas Patocka
2018-05-23 20:57 ` Mikulas Patocka
2018-05-28 13:52 ` Mikulas Patocka
2018-05-28 13:52 ` Mikulas Patocka
2018-05-28 17:41 ` Dan Williams
2018-05-28 17:41 ` Dan Williams
2018-05-30 13:42 ` [dm-devel] " Jeff Moyer
2018-05-30 13:42 ` Jeff Moyer
2018-05-30 13:51 ` Mikulas Patocka
2018-05-30 13:51 ` Mikulas Patocka
2018-05-30 13:52 ` Jeff Moyer
2018-05-30 13:52 ` Jeff Moyer
2018-05-24 8:15 ` Mikulas Patocka
2018-05-24 8:15 ` Mikulas Patocka
2018-05-25 3:12 ` Dan Williams
2018-05-25 6:17 ` Mikulas Patocka
2018-05-25 12:51 ` Mike Snitzer
2018-05-25 12:51 ` Mike Snitzer
2018-05-25 15:57 ` Dan Williams
2018-05-25 15:57 ` Dan Williams
2018-05-26 7:02 ` Mikulas Patocka
2018-05-26 7:02 ` Mikulas Patocka
2018-05-26 15:26 ` Dan Williams
2018-05-26 15:26 ` Dan Williams
2018-05-28 13:32 ` Mikulas Patocka
2018-05-28 13:32 ` Mikulas Patocka
2018-05-28 18:14 ` Dan Williams
2018-05-28 18:14 ` Dan Williams
2018-05-30 13:07 ` Mikulas Patocka
2018-05-30 13:07 ` Mikulas Patocka
2018-05-30 13:16 ` Mike Snitzer
2018-05-30 13:16 ` Mike Snitzer
2018-05-30 13:21 ` Mikulas Patocka
2018-05-30 13:21 ` Mikulas Patocka
2018-05-30 13:26 ` Mike Snitzer
2018-05-30 13:26 ` Mike Snitzer
2018-05-30 13:33 ` Mikulas Patocka
2018-05-30 13:33 ` Mikulas Patocka
2018-05-30 13:54 ` Mike Snitzer
2018-05-30 13:54 ` Mike Snitzer
2018-05-30 14:09 ` Mikulas Patocka
2018-05-30 14:09 ` Mikulas Patocka
2018-05-30 14:21 ` Mike Snitzer
2018-05-30 14:21 ` Mike Snitzer
2018-05-30 14:46 ` Mikulas Patocka
2018-05-30 14:46 ` Mikulas Patocka
2018-05-31 3:42 ` Mike Snitzer
2018-05-31 3:42 ` Mike Snitzer
2018-06-03 15:03 ` Mikulas Patocka
2018-06-03 15:03 ` Mikulas Patocka
2018-05-31 3:39 ` Mike Snitzer
2018-05-31 3:39 ` Mike Snitzer
2018-05-31 8:16 ` Mikulas Patocka
2018-05-31 8:16 ` Mikulas Patocka
2018-05-31 12:09 ` Mike Snitzer
2018-05-31 12:09 ` Mike Snitzer
2018-05-30 15:58 ` Dan Williams
2018-05-30 15:58 ` Dan Williams
2018-05-30 22:39 ` Dan Williams
2018-05-30 22:39 ` Dan Williams
2018-05-31 8:19 ` Mikulas Patocka
2018-05-31 8:19 ` Mikulas Patocka
2018-05-31 14:51 ` Dan Williams
2018-05-31 14:51 ` Dan Williams
2018-05-31 15:31 ` Mikulas Patocka
2018-05-31 15:31 ` Mikulas Patocka
2018-05-31 16:39 ` Dan Williams
2018-05-31 16:39 ` Dan Williams
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