Re: [Qemu-devel] [PATCH v2 11/16] postcopy: Mask fault addresses to huge page boundary

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Laurent Vivier (lvivier@redhat.com) wrote:
> On 06/02/2017 18:33, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> > 
> > Currently the fault address received by userfault is rounded to
> > the host page boundary and a host page is requested from the source.
> > Use the current RAMBlock page size instead of the general host page
> > size so that for RAMBlocks backed by huge pages we request the whole
> > huge page.
> > 
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > Reviewed-by: Juan Quintela <quintela@redhat.com>
> > ---
> >  include/exec/memory.h    | 1 -
> >  migration/postcopy-ram.c | 7 +++----
> >  2 files changed, 3 insertions(+), 5 deletions(-)
> > 
> > diff --git a/include/exec/memory.h b/include/exec/memory.h
> > index 987f925..c428891 100644
> > --- a/include/exec/memory.h
> > +++ b/include/exec/memory.h
> > @@ -1614,7 +1614,6 @@ MemTxResult address_space_read_continue(AddressSpace *as, hwaddr addr,
> >  MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr,
> >                                      MemTxAttrs attrs, uint8_t *buf, int len);
> >  void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr);
> > -
> >  static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write)
> >  {
> >      if (is_write) {
> 
> This hunk removing one blank line is strange...

Oops, cleaned up.

Dave

> > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> > index 4c736d2..03cbd6e 100644
> > --- a/migration/postcopy-ram.c
> > +++ b/migration/postcopy-ram.c
> > @@ -403,7 +403,6 @@ static void *postcopy_ram_fault_thread(void *opaque)
> >      MigrationIncomingState *mis = opaque;
> >      struct uffd_msg msg;
> >      int ret;
> > -    size_t hostpagesize = getpagesize();
> >      RAMBlock *rb = NULL;
> >      RAMBlock *last_rb = NULL; /* last RAMBlock we sent part of */
> >  
> > @@ -470,7 +469,7 @@ static void *postcopy_ram_fault_thread(void *opaque)
> >              break;
> >          }
> >  
> > -        rb_offset &= ~(hostpagesize - 1);
> > +        rb_offset &= ~(qemu_ram_pagesize(rb) - 1);
> >          trace_postcopy_ram_fault_thread_request(msg.arg.pagefault.address,
> >                                                  qemu_ram_get_idstr(rb),
> >                                                  rb_offset);
> > @@ -482,11 +481,11 @@ static void *postcopy_ram_fault_thread(void *opaque)
> >          if (rb != last_rb) {
> >              last_rb = rb;
> >              migrate_send_rp_req_pages(mis, qemu_ram_get_idstr(rb),
> > -                                     rb_offset, hostpagesize);
> > +                                     rb_offset, qemu_ram_pagesize(rb));
> >          } else {
> >              /* Save some space */
> >              migrate_send_rp_req_pages(mis, NULL,
> > -                                     rb_offset, hostpagesize);
> > +                                     rb_offset, qemu_ram_pagesize(rb));
> >          }
> >      }
> >      trace_postcopy_ram_fault_thread_exit();
> > 
> Reviewed-by: Laurent Vivier <lvivier@redhat.com>
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK