From: Borislav Petkov <bp@alien8.de>
To: James Morse <james.morse@arm.com>
Cc: jonathan.zhang@cavium.com, Rafael Wysocki <rjw@rjwysocki.net>,
Tony Luck <tony.luck@intel.com>,
linux-mm@kvack.org, Marc Zyngier <marc.zyngier@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Tyler Baicar <tbaicar@codeaurora.org>,
Will Deacon <will.deacon@arm.com>,
Dongjiu Geng <gengdongjiu@huawei.com>,
linux-acpi@vger.kernel.org, Punit Agrawal <punit.agrawal@arm.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, Len Brown <lenb@kernel.org>
Subject: Re: [PATCH v6 00/18] APEI in_nmi() rework
Date: Thu, 4 Oct 2018 17:15:55 +0200 [thread overview]
Message-ID: <20181004151555.GN1864@zn.tnic> (raw)
In-Reply-To: <c04d1b78-122b-d7f2-5a75-3d9c56386b11@arm.com>
On Wed, Oct 03, 2018 at 06:50:38PM +0100, James Morse wrote:
...
> The non-ghes HEST entries have a "number of records to pre-allocate" too, we
> could make this memory pool something hest.c looks after, but I can't see if the
> other error sources use those values.
Thanks for the detailed analysis!
> Hmmm, The size is capped to 64K, we could ignore the firmware description of the
> memory requirements, and allocate SZ_64K each time. Doing it per-GHES is still
> the only way to avoid allocating nmi-safe memory for irqs.
Right, so I'm thinking a lot simpler: allocate a pool which should
be large enough to handle all situations and drop all that logic
which recomputes and reallocates pool size. Just a static thing which
JustWorks(tm).
For a couple of reasons:
- you state it above: all those synchronization issues are gone with a
prellocated pool
- 64K per-GHES pool is nothing if you consider the machines this thing
runs on - fat servers with lotsa memory. And RAS there *is* important.
And TBH 64K is nothing even on a small client sporting gigabytes of
memory.
- code is a lot simpler and cleaner - you don't need all that pool
expanding and shrinking. I mean, I'm all for smarter solutions if they
have any clear advantages warranting the complication but this is a
lot of machinery just so that we can save a couple of KBs. Which, as a
whole, sounds just too much to me.
But this is just me.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de>
To: James Morse <james.morse@arm.com>
Cc: linux-acpi@vger.kernel.org, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
Marc Zyngier <marc.zyngier@arm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
Will Deacon <will.deacon@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Rafael Wysocki <rjw@rjwysocki.net>, Len Brown <lenb@kernel.org>,
Tony Luck <tony.luck@intel.com>,
Tyler Baicar <tbaicar@codeaurora.org>,
Dongjiu Geng <gengdongjiu@huawei.com>,
Xie XiuQi <xiexiuqi@huawei.com>,
Punit Agrawal <punit.agrawal@arm.com>,
jonathan.zhang@cavium.com
Subject: Re: [PATCH v6 00/18] APEI in_nmi() rework
Date: Thu, 4 Oct 2018 17:15:55 +0200 [thread overview]
Message-ID: <20181004151555.GN1864@zn.tnic> (raw)
In-Reply-To: <c04d1b78-122b-d7f2-5a75-3d9c56386b11@arm.com>
On Wed, Oct 03, 2018 at 06:50:38PM +0100, James Morse wrote:
...
> The non-ghes HEST entries have a "number of records to pre-allocate" too, we
> could make this memory pool something hest.c looks after, but I can't see if the
> other error sources use those values.
Thanks for the detailed analysis!
> Hmmm, The size is capped to 64K, we could ignore the firmware description of the
> memory requirements, and allocate SZ_64K each time. Doing it per-GHES is still
> the only way to avoid allocating nmi-safe memory for irqs.
Right, so I'm thinking a lot simpler: allocate a pool which should
be large enough to handle all situations and drop all that logic
which recomputes and reallocates pool size. Just a static thing which
JustWorks(tm).
For a couple of reasons:
- you state it above: all those synchronization issues are gone with a
prellocated pool
- 64K per-GHES pool is nothing if you consider the machines this thing
runs on - fat servers with lotsa memory. And RAS there *is* important.
And TBH 64K is nothing even on a small client sporting gigabytes of
memory.
- code is a lot simpler and cleaner - you don't need all that pool
expanding and shrinking. I mean, I'm all for smarter solutions if they
have any clear advantages warranting the complication but this is a
lot of machinery just so that we can save a couple of KBs. Which, as a
whole, sounds just too much to me.
But this is just me.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
WARNING: multiple messages have this Message-ID (diff)
From: bp@alien8.de (Borislav Petkov)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 00/18] APEI in_nmi() rework
Date: Thu, 4 Oct 2018 17:15:55 +0200 [thread overview]
Message-ID: <20181004151555.GN1864@zn.tnic> (raw)
In-Reply-To: <c04d1b78-122b-d7f2-5a75-3d9c56386b11@arm.com>
On Wed, Oct 03, 2018 at 06:50:38PM +0100, James Morse wrote:
...
> The non-ghes HEST entries have a "number of records to pre-allocate" too, we
> could make this memory pool something hest.c looks after, but I can't see if the
> other error sources use those values.
Thanks for the detailed analysis!
> Hmmm, The size is capped to 64K, we could ignore the firmware description of the
> memory requirements, and allocate SZ_64K each time. Doing it per-GHES is still
> the only way to avoid allocating nmi-safe memory for irqs.
Right, so I'm thinking a lot simpler: allocate a pool which should
be large enough to handle all situations and drop all that logic
which recomputes and reallocates pool size. Just a static thing which
JustWorks(tm).
For a couple of reasons:
- you state it above: all those synchronization issues are gone with a
prellocated pool
- 64K per-GHES pool is nothing if you consider the machines this thing
runs on - fat servers with lotsa memory. And RAS there *is* important.
And TBH 64K is nothing even on a small client sporting gigabytes of
memory.
- code is a lot simpler and cleaner - you don't need all that pool
expanding and shrinking. I mean, I'm all for smarter solutions if they
have any clear advantages warranting the complication but this is a
lot of machinery just so that we can save a couple of KBs. Which, as a
whole, sounds just too much to me.
But this is just me.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2018-10-04 15:15 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-21 22:16 [PATCH v6 00/18] APEI in_nmi() rework James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` [PATCH v6 01/18] ACPI / APEI: Move the estatus queue code up, and under its own ifdef James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` [PATCH v6 02/18] ACPI / APEI: Generalise the estatus queue's add/remove and notify code James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` [PATCH v6 03/18] ACPI / APEI: don't wait to serialise with oops messages when panic()ing James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` [PATCH v6 04/18] ACPI / APEI: Switch NOTIFY_SEA to use the estatus queue James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-28 17:04 ` Borislav Petkov
2018-09-28 17:04 ` Borislav Petkov
2018-09-28 17:04 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 05/18] ACPI / APEI: Make estatus queue a Kconfig symbol James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-01 17:59 ` Borislav Petkov
2018-10-01 17:59 ` Borislav Petkov
2018-10-01 17:59 ` Borislav Petkov
2018-10-03 17:50 ` James Morse
2018-10-03 17:50 ` James Morse
2018-10-03 17:50 ` James Morse
2018-10-04 17:34 ` Borislav Petkov
2018-10-04 17:34 ` Borislav Petkov
2018-10-04 17:34 ` Borislav Petkov
2018-10-12 17:17 ` James Morse
2018-10-12 17:17 ` James Morse
2018-10-12 17:17 ` James Morse
2018-10-12 18:10 ` Borislav Petkov
2018-10-12 18:10 ` Borislav Petkov
2018-10-12 18:10 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 06/18] KVM: arm/arm64: Add kvm_ras.h to collect kvm specific RAS plumbing James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 9:57 ` Borislav Petkov
2018-10-12 9:57 ` Borislav Petkov
2018-10-12 9:57 ` Borislav Petkov
2018-10-12 17:18 ` James Morse
2018-10-12 17:18 ` James Morse
2018-10-12 17:18 ` James Morse
2018-09-21 22:16 ` [PATCH v6 07/18] arm64: KVM/mm: Move SEA handling behind a single 'claim' interface James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 10:02 ` Borislav Petkov
2018-10-12 10:02 ` Borislav Petkov
2018-10-12 10:02 ` Borislav Petkov
2018-10-12 17:18 ` James Morse
2018-10-12 17:18 ` James Morse
2018-10-12 17:18 ` James Morse
2018-09-21 22:16 ` [PATCH v6 08/18] ACPI / APEI: Move locking to the notification helper James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 11:08 ` Borislav Petkov
2018-10-12 11:08 ` Borislav Petkov
2018-10-12 11:08 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 09/18] ACPI / APEI: Let the notification helper specify the fixmap slot James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 11:14 ` Borislav Petkov
2018-10-12 11:14 ` Borislav Petkov
2018-10-12 11:14 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 10/18] ACPI / APEI: preparatory split of ghes->estatus James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 16:37 ` Borislav Petkov
2018-10-12 16:37 ` Borislav Petkov
2018-10-12 16:37 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 11/18] ACPI / APEI: Remove silent flag from ghes_read_estatus() James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-10-12 16:55 ` Borislav Petkov
2018-10-12 16:55 ` Borislav Petkov
2018-10-12 16:55 ` Borislav Petkov
2018-09-21 22:16 ` [PATCH v6 12/18] ACPI / APEI: Don't store CPER records physical address in struct ghes James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:16 ` James Morse
2018-09-21 22:17 ` [PATCH v6 13/18] ACPI / APEI: Don't update struct ghes' flags in read/clear estatus James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-10-12 17:14 ` Borislav Petkov
2018-10-12 17:14 ` Borislav Petkov
2018-10-12 17:14 ` Borislav Petkov
2018-09-21 22:17 ` [PATCH v6 14/18] ACPI / APEI: Split ghes_read_estatus() to read CPER length James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-10-12 17:25 ` Borislav Petkov
2018-10-12 17:25 ` Borislav Petkov
2018-10-12 17:25 ` Borislav Petkov
2018-09-21 22:17 ` [PATCH v6 15/18] ACPI / APEI: Only use queued estatus entry during _in_nmi_notify_one() James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-10-12 17:34 ` Borislav Petkov
2018-10-12 17:34 ` Borislav Petkov
2018-10-12 17:34 ` Borislav Petkov
2018-09-21 22:17 ` [PATCH v6 16/18] ACPI / APEI: Split fixmap pages for arm64 NMI-like notifications James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` [PATCH v6 17/18] mm/memory-failure: increase queued recovery work's priority James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-10-15 16:49 ` Borislav Petkov
2018-10-15 16:49 ` Borislav Petkov
2018-10-15 16:49 ` Borislav Petkov
2018-10-16 7:43 ` Peter Zijlstra
2018-10-16 7:43 ` Peter Zijlstra
2018-10-16 7:43 ` Peter Zijlstra
2018-09-21 22:17 ` [PATCH v6 18/18] arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work James Morse
2018-09-21 22:17 ` James Morse
2018-09-21 22:17 ` James Morse
2018-09-25 12:45 ` [PATCH v6 00/18] APEI in_nmi() rework Borislav Petkov
2018-09-25 12:45 ` Borislav Petkov
2018-09-25 12:45 ` Borislav Petkov
2018-10-03 17:50 ` James Morse
2018-10-03 17:50 ` James Morse
2018-10-03 17:50 ` James Morse
2018-10-04 15:15 ` Borislav Petkov [this message]
2018-10-04 15:15 ` Borislav Petkov
2018-10-04 15:15 ` Borislav Petkov
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