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charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.39, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , Juan Quintela , Pankaj Gupta , "Michael S. Tsirkin" , teawater , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , Alex Williamson , Marek Kedzierski , Paolo Bonzini , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Andrey Gruzdev , Wei Yang Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Sep 02, 2021 at 03:14:31PM +0200, David Hildenbrand wrote: > Let's factor out prefaulting/populating to make further changes easier to > review. While at it, use the actual page size of the ramblock, which > defaults to qemu_real_host_page_size for anonymous memory. > > Signed-off-by: David Hildenbrand > --- > migration/ram.c | 21 ++++++++++++--------- > 1 file changed, 12 insertions(+), 9 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index e1c158dc92..de47650c90 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1639,6 +1639,17 @@ out: > return ret; > } > > +static inline void populate_range(RAMBlock *block, ram_addr_t offset, > + ram_addr_t size) > +{ > + for (; offset < size; offset += block->page_size) { > + char tmp = *((char *)block->host + offset); > + > + /* Don't optimize the read out */ > + asm volatile("" : "+r" (tmp)); > + } > +} If to make it a common function, make it populate_range_read()? Just to identify from RW, as we'll fill the holes with zero pages only, not doing page allocations yet, so not a complete "populate". That'll be good enough for live snapshot as uffd-wp works for zero pages, however I'm just afraid it may stop working for some new users of it when zero pages won't suffice. Maybe some comment would help too? -- Peter Xu