From: Jeff Moyer <jmoyer@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Jens Axboe <axboe@fb.com>, Jan Kara <jack@suse.cz>,
linux-nvdimm <linux-nvdimm@ml01.01.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
david <david@fromorbit.com>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2 1/5] pmem, dax: clean up clear_pmem()
Date: Wed, 28 Oct 2015 17:01:30 -0400 [thread overview]
Message-ID: <x49a8r2aes5.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <CAPcyv4jGPaoZAHSUqWg+2yqN=jCBTEivJauKa-Mr58cFkDF+CQ@mail.gmail.com> (Dan Williams's message of "Thu, 22 Oct 2015 15:29:33 -0700")
Dan Williams <dan.j.williams@intel.com> writes:
> On Thu, Oct 22, 2015 at 1:48 PM, Jeff Moyer <jmoyer@redhat.com> wrote:
>> Dan Williams <dan.j.williams@intel.com> writes:
>>
>>> Both, __dax_pmd_fault, and clear_pmem() were taking special steps to
>>> clear memory a page at a time to take advantage of non-temporal
>>> clear_page() implementations. However, x86_64 does not use
>>> non-temporal instructions for clear_page(), and arch_clear_pmem() was
>>> always incurring the cost of __arch_wb_cache_pmem().
>>>
>>> Clean up the assumption that doing clear_pmem() a page at a time is more
>>> performant.
>>
>> Wouldn't another solution be to actually use non-temporal stores?
>
> Sure.
>
>> Why did you choose to punt?
>
> Just a priority call at this point. Patches welcome of course ;-).
OK. Patch is harmless.
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
next prev parent reply other threads:[~2015-10-28 21:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-22 17:10 [PATCH v2 0/5] block, dax: updates for 4.4 Dan Williams
2015-10-22 17:10 ` [PATCH v2 1/5] pmem, dax: clean up clear_pmem() Dan Williams
2015-10-22 20:48 ` Jeff Moyer
2015-10-22 22:29 ` Dan Williams
2015-10-28 21:01 ` Jeff Moyer [this message]
2015-10-27 17:31 ` Ross Zwisler
2015-10-22 17:10 ` [PATCH v2 2/5] dax: increase granularity of dax_clear_blocks() operations Dan Williams
2015-10-22 21:04 ` Jeff Moyer
2015-10-22 22:57 ` Williams, Dan J
2015-10-28 21:02 ` Jeff Moyer
2015-10-22 17:10 ` [PATCH v2 3/5] block, dax: fix lifetime of in-kernel dax mappings with dax_map_atomic() Dan Williams
2015-10-28 20:15 ` Jeff Moyer
2015-10-22 17:10 ` [PATCH v2 4/5] block: introduce bdev_file_inode() Dan Williams
2015-10-22 20:37 ` Jan Kara
2015-10-28 20:16 ` Jeff Moyer
2015-10-22 17:10 ` [PATCH v2 5/5] block: enable dax for raw block devices Dan Williams
2015-10-28 20:50 ` Jeff Moyer
2015-10-29 7:14 ` Dan Williams
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