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From: Robert Richter <rrichter@marvell.com>
To: James Morse <james.morse@arm.com>
Cc: Borislav Petkov <bp@alien8.de>, Tony Luck <tony.luck@intel.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 11/21] EDAC, ghes: Unify trace_mc_event() code with edac_mc driver
Date: Thu, 13 Jun 2019 22:23:18 +0000
Message-ID: <20190613222305.eqvpom2bgcavq5it@rric.localdomain> (raw)
In-Reply-To: <1fac170a-f461-a779-9e82-5b4a0fa2c154@arm.com>

On 04.06.19 18:15:50, James Morse wrote:
> On 03/06/2019 14:10, Robert Richter wrote:
> > The +1 looks odd to me also for the edac_mc driver, but I need to take
> > a closer look here as well as some logs suggest the grain is
> > calculated correctly.
> 
> My theory on this is that ghes_edac.c is generating a grain like 0x1000, fls() does the
> right thing. Other edac drivers are generating a grain like 0xfff to describe the same
> size, fls() is now off-by-one, hence the addition.
> I don't have a platform where I can trigger any other edac driver to test this though.
> 
> The way round this would be to put the grain_bits in struct edac_raw_error_desc so that
> ghes_edac.c can calculate it directly.

I think the grain calculation in edac_mc is broken from the beginning:

 53f2d0289875 RAS: Add a tracepoint for reporting memory controller events

The log we see in the patch desc is:

 mc_event: 1 Corrected error:memory read on memory stick DIMM_1A (mc:0 location:0:0:0 page:0x586b6e offset:0xa66 grain:32 syndrome:0x0 area:DMA)

The grain reported in mc_event there is probably 8 (quad word,
granularity in bytes) and calculates as follows:

 dimm->grain = 8
 e->grain = dimm->grain
 grain_bits = fls_long(e->grain) + 1 = 4 + 1 = 5
 __entry->grain_bits = grain_bits
 TP_printk() = 1 << __entry->grain_bits = 2 << 5 = 32

So the reported grain of 32 should actually be 8.

I think the following is correct:

 grain_bits = fls_long(e->grain ? e->grain - 1 : 0);

This also handles the case if e->grain is not a power of 2.

Thoughts?

-Robert

  reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-29  8:44 [PATCH 00/21] EDAC, mc, ghes: Fixes and updates to improve memory error reporting Robert Richter
2019-05-29  8:44 ` [PATCH 01/21] EDAC, mc: Fix edac_mc_find() in case no device is found Robert Richter
2019-05-29  8:44 ` [PATCH 02/21] EDAC: Fixes to use put_device() after device_add() errors Robert Richter
2019-06-11 17:28   ` Borislav Petkov
2019-06-12 17:17     ` Robert Richter
2019-05-29  8:44 ` [PATCH 03/21] EDAC: Kill EDAC_DIMM_PTR() macro Robert Richter
2019-05-29  8:44 ` [PATCH 04/21] EDAC: Kill EDAC_DIMM_OFF() macro Robert Richter
2019-05-29  8:44 ` [PATCH 05/21] EDAC: Introduce mci_for_each_dimm() iterator Robert Richter
2019-05-29  8:44 ` [PATCH 06/21] EDAC, mc: Cleanup _edac_mc_free() code Robert Richter
2019-05-29  8:44 ` [PATCH 07/21] EDAC, mc: Remove per layer counters Robert Richter
2019-05-29  8:44 ` [PATCH 08/21] EDAC, mc: Rework edac_raw_mc_handle_error() to use struct dimm_info Robert Richter
2019-05-29  8:44 ` [PATCH 09/21] EDAC, ghes: Use standard kernel macros for page calculations Robert Richter
2019-05-29 15:13   ` James Morse
2019-05-29  8:44 ` [PATCH 10/21] EDAC, ghes: Remove pvt->detail_location string Robert Richter
2019-05-29 15:13   ` James Morse
2019-06-12 18:13     ` Robert Richter
2019-05-29  8:44 ` [PATCH 11/21] EDAC, ghes: Unify trace_mc_event() code with edac_mc driver Robert Richter
2019-05-29 15:12   ` James Morse
2019-06-03 13:10     ` Robert Richter
2019-06-04 17:15       ` James Morse
2019-06-13 22:23         ` Robert Richter [this message]
2019-05-29  8:44 ` [PATCH 12/21] EDAC, ghes: Add support for legacy API counters Robert Richter
2019-05-29 15:13   ` James Morse
2019-06-12 18:41     ` Robert Richter
2019-06-19 17:22       ` James Morse
2019-06-20  6:55         ` Robert Richter
2019-06-26  9:33           ` James Morse
2019-06-26 10:27             ` Robert Richter
2019-05-29  8:44 ` [PATCH 13/21] EDAC, ghes: Rework memory hierarchy detection Robert Richter
2019-05-29 15:06   ` James Morse
2019-05-31 13:41     ` Robert Richter
2019-05-29  8:44 ` [PATCH 14/21] EDAC, ghes: Extract numa node information for each dimm Robert Richter
2019-05-29 17:51   ` James Morse
2019-06-13 20:52     ` Robert Richter
2019-05-29  8:44 ` [PATCH 15/21] EDAC, ghes: Moving code around ghes_edac_register() Robert Richter
2019-05-29  8:44 ` [PATCH 16/21] EDAC, ghes: Create one memory controller device per node Robert Richter
2019-05-29  8:44 ` [PATCH 17/21] EDAC, ghes: Fill sysfs with the DMI DIMM label information Robert Richter
2019-05-29  8:44 ` [PATCH 18/21] EDAC, mc: Introduce edac_mc_alloc_by_dimm() for per dimm allocation Robert Richter
2019-05-29  8:44 ` [PATCH 19/21] EDAC, ghes: Identify dimm by node, card, module and handle Robert Richter
2019-05-29  8:44 ` [PATCH 20/21] EDAC, ghes: Enable per-layer reporting based on card/module Robert Richter
2019-05-29  8:44 ` [PATCH 21/21] EDAC, Documentation: Describe CPER module definition and DIMM ranks Robert Richter
2019-05-29 14:54 ` [PATCH 00/21] EDAC, mc, ghes: Fixes and updates to improve memory error reporting Borislav Petkov
2019-05-31 14:48   ` Robert Richter

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