On 07/03/2013 08:14 PM, Borislav Petkov wrote:
On Tue, Jul 02, 2013 at 05:02:48PM +0530, Naveen N. Rao wrote:
Here is the updated patch. I also added printk_ratelimit() in line with the
rest of the GHES code.

Thanks,
Naveen

--
If the firmware indicates in GHES error data entry that the error threshold
has exceeded for a corrected error event, then we try to soft-offline the
page. This could be called in interrupt context, so we queue this up similar
to how we handle memory failure scenarios.


Signed-off-by: Naveen N. Rao <[email protected]>
---
  drivers/acpi/apei/ghes.c |   38 +++++++++++++++++++++++++++++---------
  include/linux/mm.h       |    1 +
  mm/memory-failure.c      |    5 ++++-
  3 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index fcd7d91..74ef688 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -409,6 +409,34 @@ static void ghes_clear_estatus(struct ghes *ghes)
        ghes->flags &= ~GHES_TO_CLEAR;
  }

+static void ghes_handle_memory_failure(struct acpi_hest_generic_data *gdata, 
int sev)
+{
+#ifdef CONFIG_ACPI_APEI_MEMORY_FAILURE
+       int sec_sev = ghes_severity(gdata->error_severity);
+       struct cper_sec_mem_err *mem_err;
+       mem_err = (struct cper_sec_mem_err *)(gdata+1);

A newline here please. Also, spaces around '+'.

This was borrowed from existing code in ghes_do_proc(), but yes, let me make this change.


+       if (sec_sev == GHES_SEV_CORRECTED &&
+           (gdata->flags & CPER_SEC_ERROR_THRESHOLD_EXCEEDED) &&
+           (mem_err->validation_bits & CPER_MEM_VALID_PHYSICAL_ADDRESS)) {
+               unsigned long pfn;

This pfn is defined twice, move it up to the beginning of the function.

Ok.


+               pfn = mem_err->physical_addr >> PAGE_SHIFT;
+               if (pfn_valid(pfn))
+                       memory_failure_queue(pfn, 0, MF_SOFT_OFFLINE);
+               else if (printk_ratelimit())
+                       pr_warning(FW_WARN GHES_PFX

WARNING: Prefer printk_ratelimited or pr_<level>_ratelimited to printk_ratelimit
#35: FILE: drivers/acpi/apei/ghes.c:425:
+               else if (printk_ratelimit())

Please run your patches through checkpatch.pl first.

I did run checkpatch.pl, but chose to ignore this warning. ghes.c uses printk_ratelimit() [hence "in line with the rest of the ghes code" in patch description] and I felt using it is better in this scenario given there will be other messages being printed by the rest of the APEI code. So, rate-limiting these messages globally seems better rather than doing locally using pr_warn_ratelimited()


This requested change will even simplify the code (ontop of your patch):

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 74ef6882bca9..87e11d468f6b 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -422,10 +422,10 @@ static void ghes_handle_memory_failure(struct 
acpi_hest_generic_data *gdata, int
                pfn = mem_err->physical_addr >> PAGE_SHIFT;
                if (pfn_valid(pfn))
                        memory_failure_queue(pfn, 0, MF_SOFT_OFFLINE);
-               else if (printk_ratelimit())
-                       pr_warning(FW_WARN GHES_PFX
-                       "Invalid address in generic error data: %#llx\n",
-                       mem_err->physical_addr);
+               else
+                       pr_warn_ratelimited(FW_WARN GHES_PFX
+                                           "Invalid address in generic error data: 
%#llx\n",
+                                           mem_err->physical_addr);
        }
        if (sev == GHES_SEV_RECOVERABLE &&
            sec_sev == GHES_SEV_RECOVERABLE &&
---



+                       "Invalid address in generic error data: %#llx\n",
+                       mem_err->physical_addr);
+       }
+       if (sev == GHES_SEV_RECOVERABLE &&
+           sec_sev == GHES_SEV_RECOVERABLE &&
+           mem_err->validation_bits & CPER_MEM_VALID_PHYSICAL_ADDRESS) {
+               unsigned long pfn;
+               pfn = mem_err->physical_addr >> PAGE_SHIFT;
+               memory_failure_queue(pfn, 0, 0);
+       }
+#endif
+}
+
  static void ghes_do_proc(struct ghes *ghes,
                         const struct acpi_hest_generic_status *estatus)
  {
@@ -428,15 +456,7 @@ static void ghes_do_proc(struct ghes *ghes,
                        apei_mce_report_mem_error(sev == GHES_SEV_CORRECTED,
                                                  mem_err);
  #endif
-#ifdef CONFIG_ACPI_APEI_MEMORY_FAILURE
-                       if (sev == GHES_SEV_RECOVERABLE &&
-                           sec_sev == GHES_SEV_RECOVERABLE &&
-                           mem_err->validation_bits & 
CPER_MEM_VALID_PHYSICAL_ADDRESS) {
-                               unsigned long pfn;
-                               pfn = mem_err->physical_addr >> PAGE_SHIFT;
-                               memory_failure_queue(pfn, 0, 0);
-                       }
-#endif
+                       ghes_handle_memory_failure(gdata, sev);
                }
  #ifdef CONFIG_ACPI_APEI_PCIEAER
                else if (!uuid_le_cmp(*(uuid_le *)gdata->section_type,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e0c8528..958e9efd 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1784,6 +1784,7 @@ enum mf_flags {
        MF_COUNT_INCREASED = 1 << 0,
        MF_ACTION_REQUIRED = 1 << 1,
        MF_MUST_KILL = 1 << 2,
+       MF_SOFT_OFFLINE = 1 << 3,
  };
  extern int memory_failure(unsigned long pfn, int trapno, int flags);
  extern void memory_failure_queue(unsigned long pfn, int trapno, int flags);
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ceb0c7f..0d6717e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1286,7 +1286,10 @@ static void memory_failure_work_func(struct work_struct 
*work)
                spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
                if (!gotten)
                        break;
-               memory_failure(entry.pfn, entry.trapno, entry.flags);
+               if (entry.flags & MF_SOFT_OFFLINE)
+                       soft_offline_page(pfn_to_page(entry.pfn), entry.flags);
+               else
+                       memory_failure(entry.pfn, entry.trapno, entry.flags);

The rest looks ok to me.

I'm guessing this has been tested by injecting errors...?

Yes, at least partially to ensure this works ;)

Thanks,
Naveen

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