From: Jarkko Sakkinen <jarkko@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: linux-sgx@vger.kernel.org,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/3] x86/sgx: Use sgx_free_epc_page() in sgx_reclaim_pages()
Date: Mon, 15 Mar 2021 21:06:26 +0200 [thread overview]
Message-ID: <YE+wMvw4YuDKu1xx@kernel.org> (raw)
In-Reply-To: <ab40db7a-234e-b28e-c235-0c720d2d6a5f@intel.com>
On Mon, Mar 15, 2021 at 08:32:13AM -0700, Dave Hansen wrote:
> On 3/13/21 8:01 AM, Jarkko Sakkinen wrote:
> > Replace the ad-hoc code with a sgx_free_epc_page(), in order to make sure
> > that all the relevant checks and book keeping is done, while freeing a
> > borrowed EPC page, and remove redundant code. EREMOVE inside
> > sgx_free_epc_page() does not change the semantics, as EREMOVE to an
> > uninitialize pages is a nop.
>
> ^ uninitialized
>
> I know this is a short patch, but this changelog still falls a bit short
> for me.
>
> Why is this patch a part of _this_ series? What *problem* does it
> solve, related to this series?
I'm thinking of merging sgx_epc_section and sgx_numa_node. That's why I
kept it as part of the series.
Also, in any case it's better to clean up duplicate functionality. The
code is essentially open coded implementation of sgx_free_epc_page()
without EREMOVE.
> It would also be nice to remind me why the EREMOVE is redundant. Why
> didn't we need one before? What put the page in the uninitialized
> state? Is EREMOVE guaranteed to do nothing? How expensive is it?
EREMOVE gets removed by KVM series from sgx_free_epc_page() anyway.
Maybe should re-send this patch, or series, after KVM series is merged.
Then there is no explaining with EREMOVE, as sgx_free_epc_page() won't
contain it.
/Jarkko
next prev parent reply other threads:[~2021-03-15 19:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-13 16:01 [PATCH v4 0/3] x86/sgx: NUMA Jarkko Sakkinen
2021-03-13 16:01 ` [PATCH v4 1/3] x86/sgx: Use sgx_free_epc_page() in sgx_reclaim_pages() Jarkko Sakkinen
2021-03-15 15:32 ` Dave Hansen
2021-03-15 19:06 ` Jarkko Sakkinen [this message]
2021-03-15 19:27 ` Jarkko Sakkinen
2021-03-16 12:50 ` Jarkko Sakkinen
2021-03-13 16:01 ` [PATCH v4 2/3] x86/sgx: Replace section local dirty page lists with a global list Jarkko Sakkinen
2021-03-15 16:03 ` Dave Hansen
2021-03-15 19:14 ` Jarkko Sakkinen
2021-03-15 19:47 ` Dave Hansen
2021-03-13 16:01 ` [PATCH v4 3/3] x86/sgx: Add a basic NUMA allocation scheme to sgx_alloc_epc_page() Jarkko Sakkinen
2021-03-14 11:56 ` Jarkko Sakkinen
2021-03-15 16:35 ` Dave Hansen
2021-03-15 19:23 ` Jarkko Sakkinen
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