On Mon, 26 Oct 2020 14:43:08 +0100
Philippe Mathieu-Daudé <phi...@redhat.com> wrote:
> On 10/26/20 1:40 PM, Greg Kurz wrote:
> > qemu_memalign() aborts if OOM. Drop some dead code.
> >
> > Signed-off-by: Greg Kurz <gr...@kaod.org>
> > ---
> > hw/ppc/spapr.c | 6 ------
> > hw/ppc/spapr_hcall.c | 8 ++------
> > 2 files changed, 2 insertions(+), 12 deletions(-)
> >
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 0cc19b5863a4..f098d0ee6d98 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -1521,12 +1521,6 @@ void spapr_reallocate_hpt(SpaprMachineState *spapr,
> > int shift,
> > int i;
> >
> > spapr->htab = qemu_memalign(size, size);
> > - if (!spapr->htab) {
> > - error_setg_errno(errp, errno,
> > - "Could not allocate HPT of order %d", shift);
> > - return;
>
> Wasn't the idea to use qemu_try_memalign() here?
>
Well... I have mixed feeling around this. The HTAB was first
introduced by commit:
commit f43e35255cffb6ac6230dd09d308f7909f823f96
Author: David Gibson <da...@gibson.dropbear.id.au>
Date: Fri Apr 1 15:15:22 2011 +1100
Virtual hash page table handling on pSeries machine
using qemu_mallocz(), which was aborting on OOM. It then got
replaced by g_malloc0() when qemu_mallocz() got deprecated
and eventually by qemu_memalign() when KVM support was added.
Surviving OOM when allocating the HTAB never seemed to be an
option until this commit that introduced the check:
commit c5f54f3e31bf693f70a98d4d73ea5dbe05689857
Author: David Gibson <da...@gibson.dropbear.id.au>
Date: Tue Feb 9 10:21:56 2016 +1000
pseries: Move hash page table allocation to reset time
I don't really see in the patch and in the changelog an obvious
desire to try to handle OOM.
> > - }
> > -
> > memset(spapr->htab, 0, size);
> > spapr->htab_shift = shift;
> >
> > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> > index 607740150fa2..34e146f628fb 100644
> > --- a/hw/ppc/spapr_hcall.c
> > +++ b/hw/ppc/spapr_hcall.c
> > @@ -361,12 +361,8 @@ static void *hpt_prepare_thread(void *opaque)
> > size_t size = 1ULL << pending->shift;
> >
> > pending->hpt = qemu_memalign(size, size);
> > - if (pending->hpt) {
> > - memset(pending->hpt, 0, size);
> > - pending->ret = H_SUCCESS;
> > - } else {
> > - pending->ret = H_NO_MEM;
>
> Ditto.
>
This one was introduced by commit:
commit 0b0b831016ae93bc14698a5d7202eb77feafea75
Author: David Gibson <da...@gibson.dropbear.id.au>
Date: Fri May 12 15:46:49 2017 +1000
pseries: Implement HPT resizing
I agree that maybe the intent here could have been to use qemu_try_memalign(),
but again I don't quite see any strong justification to handle OOM in the
changelog.
David,
Any insight to share ?
> > - }
> > + memset(pending->hpt, 0, size);
> > + pending->ret = H_SUCCESS;
> >
> > qemu_mutex_lock_iothread();
> >
>
