From: Jeff Moyer <jmoyer@redhat.com> To: Nicholas Piggin <npiggin@gmail.com> Cc: "Luck, Tony" <tony.luck@intel.com>, linux-nvdimm <linux-nvdimm@lists.01.org>, Michael Ellerman <mpe@ellerman.id.au>, Matthew Wilcox <mawilcox@microsoft.com>, linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, Christoph Hellwig <hch@lst.de> Subject: Re: [RESEND 2/3] powerpc/memcpy: Add memcpy_mcsafe for pmem Date: Thu, 05 Apr 2018 16:40:26 -0400 [thread overview] Message-ID: <x496055gzet.fsf@segfault.boston.devel.redhat.com> (raw) In-Reply-To: <20180405164508.7a15a770@roar.ozlabs.ibm.com> (Nicholas Piggin's message of "Thu, 5 Apr 2018 16:45:08 +1000") Nicholas Piggin <npiggin@gmail.com> writes: > On Thu, 5 Apr 2018 15:53:07 +1000 > Balbir Singh <bsingharora@gmail.com> wrote: >> I'm thinking about it, I wonder what "bytes remaining" mean in pmem context >> in the context of a machine check exception. Also, do we want to be byte >> accurate or cache-line accurate for the bytes remaining? The former is much >> easier than the latter :) > > The ideal would be a linear measure of how much of your copy reached > (or can reach) non-volatile storage with nothing further copied. You > may have to allow for some relaxing of the semantics depending on > what the architecture can support. I think you've got that backwards. memcpy_mcsafe is used to copy *from* persistent memory. The idea is to catch errors when reading pmem, not writing to it. > What's the problem with just counting bytes copied like usercopy -- > why is that harder than cacheline accuracy? He said the former (i.e. bytes) is easier. So, I think you're on the same page. :) Cheers, Jeff _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
WARNING: multiple messages have this Message-ID (diff)
From: Jeff Moyer <jmoyer@redhat.com> To: Nicholas Piggin <npiggin@gmail.com> Cc: Balbir Singh <bsingharora@gmail.com>, "Luck\, Tony" <tony.luck@intel.com>, Matthew Wilcox <mawilcox@microsoft.com>, Michael Ellerman <mpe@ellerman.id.au>, linux-nvdimm <linux-nvdimm@lists.01.org>, linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, Christoph Hellwig <hch@lst.de> Subject: Re: [RESEND 2/3] powerpc/memcpy: Add memcpy_mcsafe for pmem Date: Thu, 05 Apr 2018 16:40:26 -0400 [thread overview] Message-ID: <x496055gzet.fsf@segfault.boston.devel.redhat.com> (raw) In-Reply-To: <20180405164508.7a15a770@roar.ozlabs.ibm.com> (Nicholas Piggin's message of "Thu, 5 Apr 2018 16:45:08 +1000") Nicholas Piggin <npiggin@gmail.com> writes: > On Thu, 5 Apr 2018 15:53:07 +1000 > Balbir Singh <bsingharora@gmail.com> wrote: >> I'm thinking about it, I wonder what "bytes remaining" mean in pmem context >> in the context of a machine check exception. Also, do we want to be byte >> accurate or cache-line accurate for the bytes remaining? The former is much >> easier than the latter :) > > The ideal would be a linear measure of how much of your copy reached > (or can reach) non-volatile storage with nothing further copied. You > may have to allow for some relaxing of the semantics depending on > what the architecture can support. I think you've got that backwards. memcpy_mcsafe is used to copy *from* persistent memory. The idea is to catch errors when reading pmem, not writing to it. > What's the problem with just counting bytes copied like usercopy -- > why is that harder than cacheline accuracy? He said the former (i.e. bytes) is easier. So, I think you're on the same page. :) Cheers, Jeff
next prev parent reply other threads:[~2018-04-05 20:40 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-04-04 23:19 [RESEND 0/3] Add support for memcpy_mcsafe Balbir Singh 2018-04-04 23:19 ` Balbir Singh 2018-04-04 23:19 ` [RESEND 1/3] powerpc/mce: Bug fixes for MCE handling in kernel space Balbir Singh 2018-04-04 23:19 ` Balbir Singh 2018-04-04 23:49 ` Nicholas Piggin 2018-04-04 23:49 ` Nicholas Piggin 2018-04-05 1:11 ` Balbir Singh 2018-04-05 1:11 ` Balbir Singh 2018-04-04 23:19 ` [RESEND 2/3] powerpc/memcpy: Add memcpy_mcsafe for pmem Balbir Singh 2018-04-04 23:19 ` Balbir Singh 2018-04-04 23:57 ` Nicholas Piggin 2018-04-04 23:57 ` Nicholas Piggin 2018-04-05 3:00 ` Dan Williams 2018-04-05 3:00 ` Dan Williams 2018-04-05 5:04 ` Nicholas Piggin 2018-04-05 5:04 ` Nicholas Piggin 2018-04-05 5:53 ` Balbir Singh 2018-04-05 5:53 ` Balbir Singh 2018-04-05 6:45 ` Nicholas Piggin 2018-04-05 6:45 ` Nicholas Piggin 2018-04-05 15:00 ` Dan Williams 2018-04-05 15:00 ` Dan Williams 2018-05-01 20:57 ` Dan Williams 2018-05-01 20:57 ` Dan Williams 2018-05-02 12:36 ` Balbir Singh 2018-05-02 12:36 ` Balbir Singh 2018-04-05 20:40 ` Jeff Moyer [this message] 2018-04-05 20:40 ` Jeff Moyer 2018-04-06 1:26 ` Nicholas Piggin 2018-04-06 1:26 ` Nicholas Piggin 2018-04-06 9:25 ` Balbir Singh 2018-04-06 9:25 ` Balbir Singh 2018-04-06 15:46 ` Luck, Tony 2018-04-06 15:46 ` Luck, Tony 2018-04-04 23:19 ` [RESEND 3/3] powerpc/mce: Handle memcpy_mcsafe Balbir Singh 2018-04-04 23:19 ` Balbir Singh
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