Re: [Qemu-ppc] [Qemu-devel] [PATCH 03/10] pseries: Clean up hash page table allocation error handling

[David Gibson]

On Mon, Jan 18, 2016 at 04:17:08PM +1100, Alexey Kardashevskiy wrote:
> On 01/18/2016 03:42 PM, David Gibson wrote:
> >On Mon, Jan 18, 2016 at 01:44:00PM +1100, Alexey Kardashevskiy wrote:
> >>On 01/15/2016 11:00 PM, David Gibson wrote:
> >>>The spapr_alloc_htab() and spapr_reset_htab() functions currently handle
> >>>all errors with error_setg(&error_abort, ...).
> >>>
> >>>But really, the callers are really better placed to decide on the error
> >>>handling.  So, instead make the functions use the error propagation
> >>>infrastructure.
> >>>
> >>>In the callers we change to &error_fatal instead of &error_abort, since
> >>>this can be triggered by a bad configuration or kernel error rather than
> >>>indicating a programming error in qemu.
> >>>
> >>>While we're at it improve the messages themselves a bit, and clean up the
> >>>indentation a little.
> >>>
> >>>Signed-off-by: David Gibson <address@hidden>
> >>>---
> >>>  hw/ppc/spapr.c | 24 ++++++++++++++++--------
> >>>  1 file changed, 16 insertions(+), 8 deletions(-)
> >>>
> >>>diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> >>>index b7fd09a..d28e349 100644
> >>>--- a/hw/ppc/spapr.c
> >>>+++ b/hw/ppc/spapr.c
> >>>@@ -1016,7 +1016,7 @@ static void emulate_spapr_hypercall(PowerPCCPU *cpu)
> >>>  #define CLEAN_HPTE(_hpte)  ((*(uint64_t *)(_hpte)) &= 
> >>> tswap64(~HPTE64_V_HPTE_DIRTY))
> >>>  #define DIRTY_HPTE(_hpte)  ((*(uint64_t *)(_hpte)) |= 
> >>> tswap64(HPTE64_V_HPTE_DIRTY))
> >>>
> >>>-static void spapr_alloc_htab(sPAPRMachineState *spapr)
> >>>+static void spapr_alloc_htab(sPAPRMachineState *spapr, Error **errp)
> >>>  {
> >>>      long shift;
> >>>      int index;
> >>>@@ -1031,7 +1031,8 @@ static void spapr_alloc_htab(sPAPRMachineState 
> >>>*spapr)
> >>>           * For HV KVM, host kernel will return -ENOMEM when requested
> >>>           * HTAB size can't be allocated.
> >>>           */
> >>>-        error_setg(&error_abort, "Failed to allocate HTAB of requested 
> >>>size, try with smaller maxmem");
> >>>+        error_setg_errno(errp, -shift,
> >>>+                         "Error allocating KVM hash page table, try 
> >>>smaller maxmem");
> >>>      } else if (shift > 0) {
> >>>          /*
> >>>           * Kernel handles htab, we don't need to allocate one
> >>>@@ -1040,7 +1041,10 @@ static void spapr_alloc_htab(sPAPRMachineState 
> >>>*spapr)
> >>>           * but we don't allow booting of such guests.
> >>>           */
> >>>          if (shift != spapr->htab_shift) {
> >>>-            error_setg(&error_abort, "Failed to allocate HTAB of 
> >>>requested size, try with smaller maxmem");
> >>>+            error_setg(errp,
> >>>+                "Small allocation for KVM hash page table (%ld < %"
> >>>+                PRIu32 "), try smaller maxmem",
> >>
> >>
> >>
> >>Even though it is not in the CODING_STYLE, I have not seen anyone objecting
> >>the very good kernel's "never break user-visible strings" rule or rejecting
> >>patches with user-visible strings failing to fit 80 chars limit.
> >
> >I'm not.  Or rather, the string is already broken by the PRIu32, so
> >the newline doesn't make it any less greppable.
> 
> 
> "KVM hash page table.*smaller maxmem" stopped working. Not a big deal but I
> do not see any win in breaking strings anyway.

The problem is that the current pre-commit hooks don't agree with
you.  They seem to allow long unbroken strings, but if there's a break
like the PRIu32, they won't permit the commit.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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