| Message ID | 20191018004850.9888-6-richardw.yang@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | migration/postcopy: enable compress during postcopy | expand |
* Wei Yang (richardw.yang@linux.intel.com) wrote: > After using number of target page received to track one host page, we > could have the capability to handle random order target page arrival in > one host page. > > This is a preparation for enabling compress during postcopy. > > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> > --- > migration/ram.c | 16 +++------------- > 1 file changed, 3 insertions(+), 13 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index b5759793a9..da0596411c 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -4015,7 +4015,6 @@ static int ram_load_postcopy(QEMUFile *f) > MigrationIncomingState *mis = migration_incoming_get_current(); > /* Temporary page that is later 'placed' */ > void *postcopy_host_page = mis->postcopy_tmp_page; > - void *last_host = NULL; > bool all_zero = false; > int target_pages = 0; > > @@ -4062,24 +4061,15 @@ static int ram_load_postcopy(QEMUFile *f) > * that's moved into place later. > * The migration protocol uses, possibly smaller, target-pages > * however the source ensures it always sends all the components > - * of a host page in order. > + * of a host page in one chunk. > */ > page_buffer = postcopy_host_page + > ((uintptr_t)host & (block->page_size - 1)); > /* If all TP are zero then we can optimise the place */ > if (target_pages == 1) { > all_zero = true; > - } else { > - /* not the 1st TP within the HP */ > - if (host != (last_host + TARGET_PAGE_SIZE)) { > - error_report("Non-sequential target page %p/%p", > - host, last_host); > - ret = -EINVAL; > - break; > - } I think this is losing more protection than needed. I think you can still protect against a page from a different host-page arriving until we've placed the current host-page. So something like: if (((uintptr_t)host & ~(block->page_size - 1)) != last_host) and then set last_host to the start of the host page. Then you'll check if that flush is really working. Dave > } > > - > /* > * If it's the last part of a host page then we place the host > * page > @@ -4090,7 +4080,6 @@ static int ram_load_postcopy(QEMUFile *f) > } > place_source = postcopy_host_page; > } > - last_host = host; > > switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { > case RAM_SAVE_FLAG_ZERO: > @@ -4143,7 +4132,8 @@ static int ram_load_postcopy(QEMUFile *f) > > if (!ret && place_needed) { > /* This gets called at the last target page in the host page */ > - void *place_dest = host + TARGET_PAGE_SIZE - block->page_size; > + void *place_dest = (void *)QEMU_ALIGN_DOWN((unsigned long)host, > + block->page_size); > > if (all_zero) { > ret = postcopy_place_page_zero(mis, place_dest, > -- > 2.17.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Wed, Nov 06, 2019 at 08:08:28PM +0000, Dr. David Alan Gilbert wrote: >* Wei Yang (richardw.yang@linux.intel.com) wrote: >> After using number of target page received to track one host page, we >> could have the capability to handle random order target page arrival in >> one host page. >> >> This is a preparation for enabling compress during postcopy. >> >> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> >> --- >> migration/ram.c | 16 +++------------- >> 1 file changed, 3 insertions(+), 13 deletions(-) >> >> diff --git a/migration/ram.c b/migration/ram.c >> index b5759793a9..da0596411c 100644 >> --- a/migration/ram.c >> +++ b/migration/ram.c >> @@ -4015,7 +4015,6 @@ static int ram_load_postcopy(QEMUFile *f) >> MigrationIncomingState *mis = migration_incoming_get_current(); >> /* Temporary page that is later 'placed' */ >> void *postcopy_host_page = mis->postcopy_tmp_page; >> - void *last_host = NULL; >> bool all_zero = false; >> int target_pages = 0; >> >> @@ -4062,24 +4061,15 @@ static int ram_load_postcopy(QEMUFile *f) >> * that's moved into place later. >> * The migration protocol uses, possibly smaller, target-pages >> * however the source ensures it always sends all the components >> - * of a host page in order. >> + * of a host page in one chunk. >> */ >> page_buffer = postcopy_host_page + >> ((uintptr_t)host & (block->page_size - 1)); >> /* If all TP are zero then we can optimise the place */ >> if (target_pages == 1) { >> all_zero = true; >> - } else { >> - /* not the 1st TP within the HP */ >> - if (host != (last_host + TARGET_PAGE_SIZE)) { >> - error_report("Non-sequential target page %p/%p", >> - host, last_host); >> - ret = -EINVAL; >> - break; >> - } > >I think this is losing more protection than needed. >I think you can still protect against a page from a different host-page >arriving until we've placed the current host-page. >So something like: > > if (((uintptr_t)host & ~(block->page_size - 1)) != > last_host) > OK, looks reasonable. >and then set last_host to the start of the host page. > I think it is not necessary to update the last_host on each target page. We can just set it at the first target page. >Then you'll check if that flush is really working. > >Dave > >> } >> >> - >> /* >> * If it's the last part of a host page then we place the host >> * page >> @@ -4090,7 +4080,6 @@ static int ram_load_postcopy(QEMUFile *f) >> } >> place_source = postcopy_host_page; >> } >> - last_host = host; >> >> switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { >> case RAM_SAVE_FLAG_ZERO: >> @@ -4143,7 +4132,8 @@ static int ram_load_postcopy(QEMUFile *f) >> >> if (!ret && place_needed) { >> /* This gets called at the last target page in the host page */ >> - void *place_dest = host + TARGET_PAGE_SIZE - block->page_size; >> + void *place_dest = (void *)QEMU_ALIGN_DOWN((unsigned long)host, >> + block->page_size); >> >> if (all_zero) { >> ret = postcopy_place_page_zero(mis, place_dest, >> -- >> 2.17.1 >> >-- >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
* Wei Yang (richardw.yang@linux.intel.com) wrote: > On Wed, Nov 06, 2019 at 08:08:28PM +0000, Dr. David Alan Gilbert wrote: > >* Wei Yang (richardw.yang@linux.intel.com) wrote: > >> After using number of target page received to track one host page, we > >> could have the capability to handle random order target page arrival in > >> one host page. > >> > >> This is a preparation for enabling compress during postcopy. > >> > >> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> > >> --- > >> migration/ram.c | 16 +++------------- > >> 1 file changed, 3 insertions(+), 13 deletions(-) > >> > >> diff --git a/migration/ram.c b/migration/ram.c > >> index b5759793a9..da0596411c 100644 > >> --- a/migration/ram.c > >> +++ b/migration/ram.c > >> @@ -4015,7 +4015,6 @@ static int ram_load_postcopy(QEMUFile *f) > >> MigrationIncomingState *mis = migration_incoming_get_current(); > >> /* Temporary page that is later 'placed' */ > >> void *postcopy_host_page = mis->postcopy_tmp_page; > >> - void *last_host = NULL; > >> bool all_zero = false; > >> int target_pages = 0; > >> > >> @@ -4062,24 +4061,15 @@ static int ram_load_postcopy(QEMUFile *f) > >> * that's moved into place later. > >> * The migration protocol uses, possibly smaller, target-pages > >> * however the source ensures it always sends all the components > >> - * of a host page in order. > >> + * of a host page in one chunk. > >> */ > >> page_buffer = postcopy_host_page + > >> ((uintptr_t)host & (block->page_size - 1)); > >> /* If all TP are zero then we can optimise the place */ > >> if (target_pages == 1) { > >> all_zero = true; > >> - } else { > >> - /* not the 1st TP within the HP */ > >> - if (host != (last_host + TARGET_PAGE_SIZE)) { > >> - error_report("Non-sequential target page %p/%p", > >> - host, last_host); > >> - ret = -EINVAL; > >> - break; > >> - } > > > >I think this is losing more protection than needed. > >I think you can still protect against a page from a different host-page > >arriving until we've placed the current host-page. > >So something like: > > > > if (((uintptr_t)host & ~(block->page_size - 1)) != > > last_host) > > > > OK, looks reasonable. > > >and then set last_host to the start of the host page. > > > > I think it is not necessary to update the last_host on each target page. We > can just set it at the first target page. Yes, that would be fine. Dave > >Then you'll check if that flush is really working. > > > >Dave > > > >> } > >> > >> - > >> /* > >> * If it's the last part of a host page then we place the host > >> * page > >> @@ -4090,7 +4080,6 @@ static int ram_load_postcopy(QEMUFile *f) > >> } > >> place_source = postcopy_host_page; > >> } > >> - last_host = host; > >> > >> switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { > >> case RAM_SAVE_FLAG_ZERO: > >> @@ -4143,7 +4132,8 @@ static int ram_load_postcopy(QEMUFile *f) > >> > >> if (!ret && place_needed) { > >> /* This gets called at the last target page in the host page */ > >> - void *place_dest = host + TARGET_PAGE_SIZE - block->page_size; > >> + void *place_dest = (void *)QEMU_ALIGN_DOWN((unsigned long)host, > >> + block->page_size); > >> > >> if (all_zero) { > >> ret = postcopy_place_page_zero(mis, place_dest, > >> -- > >> 2.17.1 > >> > >-- > >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > -- > Wei Yang > Help you, Help me -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff --git a/migration/ram.c b/migration/ram.c index b5759793a9..da0596411c 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -4015,7 +4015,6 @@ static int ram_load_postcopy(QEMUFile *f) MigrationIncomingState *mis = migration_incoming_get_current(); /* Temporary page that is later 'placed' */ void *postcopy_host_page = mis->postcopy_tmp_page; - void *last_host = NULL; bool all_zero = false; int target_pages = 0; @@ -4062,24 +4061,15 @@ static int ram_load_postcopy(QEMUFile *f) * that's moved into place later. * The migration protocol uses, possibly smaller, target-pages * however the source ensures it always sends all the components - * of a host page in order. + * of a host page in one chunk. */ page_buffer = postcopy_host_page + ((uintptr_t)host & (block->page_size - 1)); /* If all TP are zero then we can optimise the place */ if (target_pages == 1) { all_zero = true; - } else { - /* not the 1st TP within the HP */ - if (host != (last_host + TARGET_PAGE_SIZE)) { - error_report("Non-sequential target page %p/%p", - host, last_host); - ret = -EINVAL; - break; - } } - /* * If it's the last part of a host page then we place the host * page @@ -4090,7 +4080,6 @@ static int ram_load_postcopy(QEMUFile *f) } place_source = postcopy_host_page; } - last_host = host; switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { case RAM_SAVE_FLAG_ZERO: @@ -4143,7 +4132,8 @@ static int ram_load_postcopy(QEMUFile *f) if (!ret && place_needed) { /* This gets called at the last target page in the host page */ - void *place_dest = host + TARGET_PAGE_SIZE - block->page_size; + void *place_dest = (void *)QEMU_ALIGN_DOWN((unsigned long)host, + block->page_size); if (all_zero) { ret = postcopy_place_page_zero(mis, place_dest,
After using number of target page received to track one host page, we could have the capability to handle random order target page arrival in one host page. This is a preparation for enabling compress during postcopy. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> --- migration/ram.c | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-)