| Message ID | 20220920225223.49052-1-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | migration: Postcopy Preempt-Full | expand |
* Peter Xu (peterx@redhat.com) wrote: > Since we use PageSearchStatus to represent a channel, it makes perfect > sense to keep last_sent_block (aka, leverage RAM_SAVE_FLAG_CONTINUE) to be > per-channel rather than global because each channel can be sending > different pages on ramblocks. > > Hence move it from RAMState into PageSearchStatus. > > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > migration/ram.c | 71 ++++++++++++++++++++++++++++--------------------- > 1 file changed, 41 insertions(+), 30 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index dbe11e1ace..fdcb61a2c8 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -89,6 +89,8 @@ XBZRLECacheStats xbzrle_counters; > struct PageSearchStatus { > /* The migration channel used for a specific host page */ > QEMUFile *pss_channel; > + /* Last block from where we have sent data */ > + RAMBlock *last_sent_block; > /* Current block being searched */ > RAMBlock *block; > /* Current page to search from */ > @@ -368,8 +370,6 @@ struct RAMState { > int uffdio_fd; > /* Last block that we have visited searching for dirty pages */ > RAMBlock *last_seen_block; > - /* Last block from where we have sent data */ > - RAMBlock *last_sent_block; > /* Last dirty target page we have sent */ > ram_addr_t last_page; > /* last ram version we have seen */ > @@ -677,16 +677,17 @@ exit: > * > * Returns the number of bytes written > * > - * @f: QEMUFile where to send the data > + * @pss: current PSS channel status > * @block: block that contains the page we want to send > * @offset: offset inside the block for the page > * in the lower bits, it contains flags > */ > -static size_t save_page_header(RAMState *rs, QEMUFile *f, RAMBlock *block, > +static size_t save_page_header(PageSearchStatus *pss, RAMBlock *block, > ram_addr_t offset) > { > size_t size, len; > - bool same_block = (block == rs->last_sent_block); > + bool same_block = (block == pss->last_sent_block); > + QEMUFile *f = pss->pss_channel; > > if (same_block) { > offset |= RAM_SAVE_FLAG_CONTINUE; > @@ -699,7 +700,7 @@ static size_t save_page_header(RAMState *rs, QEMUFile *f, RAMBlock *block, > qemu_put_byte(f, len); > qemu_put_buffer(f, (uint8_t *)block->idstr, len); > size += 1 + len; > - rs->last_sent_block = block; > + pss->last_sent_block = block; > } > return size; > } > @@ -783,17 +784,19 @@ static void xbzrle_cache_zero_page(RAMState *rs, ram_addr_t current_addr) > * -1 means that xbzrle would be longer than normal > * > * @rs: current RAM state > + * @pss: current PSS channel > * @current_data: pointer to the address of the page contents > * @current_addr: addr of the page > * @block: block that contains the page we want to send > * @offset: offset inside the block for the page > */ > -static int save_xbzrle_page(RAMState *rs, QEMUFile *file, > +static int save_xbzrle_page(RAMState *rs, PageSearchStatus *pss, > uint8_t **current_data, ram_addr_t current_addr, > RAMBlock *block, ram_addr_t offset) > { > int encoded_len = 0, bytes_xbzrle; > uint8_t *prev_cached_page; > + QEMUFile *file = pss->pss_channel; > > if (!cache_is_cached(XBZRLE.cache, current_addr, > ram_counters.dirty_sync_count)) { > @@ -858,7 +861,7 @@ static int save_xbzrle_page(RAMState *rs, QEMUFile *file, > } > > /* Send XBZRLE based compressed page */ > - bytes_xbzrle = save_page_header(rs, file, block, > + bytes_xbzrle = save_page_header(pss, block, > offset | RAM_SAVE_FLAG_XBZRLE); > qemu_put_byte(file, ENCODING_FLAG_XBZRLE); > qemu_put_be16(file, encoded_len); > @@ -1289,19 +1292,19 @@ static void ram_release_page(const char *rbname, uint64_t offset) > * Returns the size of data written to the file, 0 means the page is not > * a zero page > * > - * @rs: current RAM state > - * @file: the file where the data is saved > + * @pss: current PSS channel > * @block: block that contains the page we want to send > * @offset: offset inside the block for the page > */ > -static int save_zero_page_to_file(RAMState *rs, QEMUFile *file, > +static int save_zero_page_to_file(PageSearchStatus *pss, > RAMBlock *block, ram_addr_t offset) > { > uint8_t *p = block->host + offset; > + QEMUFile *file = pss->pss_channel; > int len = 0; > > if (buffer_is_zero(p, TARGET_PAGE_SIZE)) { > - len += save_page_header(rs, file, block, offset | RAM_SAVE_FLAG_ZERO); > + len += save_page_header(pss, block, offset | RAM_SAVE_FLAG_ZERO); > qemu_put_byte(file, 0); > len += 1; > ram_release_page(block->idstr, offset); > @@ -1314,14 +1317,14 @@ static int save_zero_page_to_file(RAMState *rs, QEMUFile *file, > * > * Returns the number of pages written. > * > - * @rs: current RAM state > + * @pss: current PSS channel > * @block: block that contains the page we want to send > * @offset: offset inside the block for the page > */ > -static int save_zero_page(RAMState *rs, QEMUFile *file, RAMBlock *block, > +static int save_zero_page(PageSearchStatus *pss, RAMBlock *block, > ram_addr_t offset) > { > - int len = save_zero_page_to_file(rs, file, block, offset); > + int len = save_zero_page_to_file(pss, block, offset); > > if (len) { > qatomic_inc(&ram_counters.duplicate); > @@ -1374,16 +1377,18 @@ static bool control_save_page(PageSearchStatus *pss, RAMBlock *block, > * > * Returns the number of pages written. > * > - * @rs: current RAM state > + * @pss: current PSS channel > * @block: block that contains the page we want to send > * @offset: offset inside the block for the page > * @buf: the page to be sent > * @async: send to page asyncly > */ > -static int save_normal_page(RAMState *rs, QEMUFile *file, RAMBlock *block, > +static int save_normal_page(PageSearchStatus *pss, RAMBlock *block, > ram_addr_t offset, uint8_t *buf, bool async) > { > - ram_transferred_add(save_page_header(rs, file, block, > + QEMUFile *file = pss->pss_channel; > + > + ram_transferred_add(save_page_header(pss, block, > offset | RAM_SAVE_FLAG_PAGE)); > if (async) { > qemu_put_buffer_async(file, buf, TARGET_PAGE_SIZE, > @@ -1423,7 +1428,7 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss) > > XBZRLE_cache_lock(); > if (rs->xbzrle_enabled && !migration_in_postcopy()) { > - pages = save_xbzrle_page(rs, pss->pss_channel, &p, current_addr, > + pages = save_xbzrle_page(rs, pss, &p, current_addr, > block, offset); > if (!rs->last_stage) { > /* Can't send this cached data async, since the cache page > @@ -1435,8 +1440,7 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss) > > /* XBZRLE overflow or normal page */ > if (pages == -1) { > - pages = save_normal_page(rs, pss->pss_channel, block, offset, > - p, send_async); > + pages = save_normal_page(pss, block, offset, p, send_async); > } > > XBZRLE_cache_unlock(); > @@ -1459,14 +1463,15 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block, > ram_addr_t offset, uint8_t *source_buf) > { > RAMState *rs = ram_state; > + PageSearchStatus *pss = &rs->pss[RAM_CHANNEL_PRECOPY]; > uint8_t *p = block->host + offset; > int ret; > > - if (save_zero_page_to_file(rs, f, block, offset)) { > + if (save_zero_page_to_file(pss, block, offset)) { > return true; > } > > - save_page_header(rs, f, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE); > + save_page_header(pss, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE); > > /* > * copy it to a internal buffer to avoid it being modified by VM > @@ -2286,7 +2291,8 @@ static bool save_page_use_compression(RAMState *rs) > * has been properly handled by compression, otherwise needs other > * paths to handle it > */ > -static bool save_compress_page(RAMState *rs, RAMBlock *block, ram_addr_t offset) > +static bool save_compress_page(RAMState *rs, PageSearchStatus *pss, > + RAMBlock *block, ram_addr_t offset) > { > if (!save_page_use_compression(rs)) { > return false; > @@ -2302,7 +2308,7 @@ static bool save_compress_page(RAMState *rs, RAMBlock *block, ram_addr_t offset) > * We post the fist page as normal page as compression will take > * much CPU resource. > */ > - if (block != rs->last_sent_block) { > + if (block != pss->last_sent_block) { > flush_compressed_data(rs); > return false; > } > @@ -2333,11 +2339,11 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss) > return res; > } > > - if (save_compress_page(rs, block, offset)) { > + if (save_compress_page(rs, pss, block, offset)) { > return 1; > } > > - res = save_zero_page(rs, pss->pss_channel, block, offset); > + res = save_zero_page(pss, block, offset); > if (res > 0) { > /* Must let xbzrle know, otherwise a previous (now 0'd) cached > * page would be stale > @@ -2469,7 +2475,7 @@ static void postcopy_preempt_choose_channel(RAMState *rs, PageSearchStatus *pss) > * If channel switched, reset last_sent_block since the old sent block > * may not be on the same channel. > */ > - rs->last_sent_block = NULL; > + pss->last_sent_block = NULL; > > trace_postcopy_preempt_switch_channel(channel); > } > @@ -2804,8 +2810,13 @@ static void ram_save_cleanup(void *opaque) > > static void ram_state_reset(RAMState *rs) > { > + int i; > + > + for (i = 0; i < RAM_CHANNEL_MAX; i++) { > + rs->pss[i].last_sent_block = NULL; > + } > + > rs->last_seen_block = NULL; > - rs->last_sent_block = NULL; > rs->last_page = 0; > rs->last_version = ram_list.version; > rs->xbzrle_enabled = false; > @@ -2999,8 +3010,8 @@ void ram_postcopy_send_discard_bitmap(MigrationState *ms) > migration_bitmap_sync(rs); > > /* Easiest way to make sure we don't resume in the middle of a host-page */ > + rs->pss[RAM_CHANNEL_PRECOPY].last_sent_block = NULL; Why don't we reset the postcopy one here as well? Dave > rs->last_seen_block = NULL; > - rs->last_sent_block = NULL; > rs->last_page = 0; > > postcopy_each_ram_send_discard(ms); > -- > 2.32.0 >
On Thu, Oct 06, 2022 at 05:59:51PM +0100, Dr. David Alan Gilbert wrote: > > @@ -2999,8 +3010,8 @@ void ram_postcopy_send_discard_bitmap(MigrationState *ms) > > migration_bitmap_sync(rs); > > > > /* Easiest way to make sure we don't resume in the middle of a host-page */ > > + rs->pss[RAM_CHANNEL_PRECOPY].last_sent_block = NULL; > > Why don't we reset the postcopy one here as well? Because ram_postcopy_send_discard_bitmap() is only called before postcopy starts, so the other field should be NULL already. Thanks,
* Peter Xu (peterx@redhat.com) wrote: > On Thu, Oct 06, 2022 at 05:59:51PM +0100, Dr. David Alan Gilbert wrote: > > > @@ -2999,8 +3010,8 @@ void ram_postcopy_send_discard_bitmap(MigrationState *ms) > > > migration_bitmap_sync(rs); > > > > > > /* Easiest way to make sure we don't resume in the middle of a host-page */ > > > + rs->pss[RAM_CHANNEL_PRECOPY].last_sent_block = NULL; > > > > Why don't we reset the postcopy one here as well? > > Because ram_postcopy_send_discard_bitmap() is only called before postcopy > starts, so the other field should be NULL already. Thanks, Ah, yes, OK Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > -- > Peter Xu >
diff --git a/migration/ram.c b/migration/ram.c index dbe11e1ace..fdcb61a2c8 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -89,6 +89,8 @@ XBZRLECacheStats xbzrle_counters; struct PageSearchStatus { /* The migration channel used for a specific host page */ QEMUFile *pss_channel; + /* Last block from where we have sent data */ + RAMBlock *last_sent_block; /* Current block being searched */ RAMBlock *block; /* Current page to search from */ @@ -368,8 +370,6 @@ struct RAMState { int uffdio_fd; /* Last block that we have visited searching for dirty pages */ RAMBlock *last_seen_block; - /* Last block from where we have sent data */ - RAMBlock *last_sent_block; /* Last dirty target page we have sent */ ram_addr_t last_page; /* last ram version we have seen */ @@ -677,16 +677,17 @@ exit: * * Returns the number of bytes written * - * @f: QEMUFile where to send the data + * @pss: current PSS channel status * @block: block that contains the page we want to send * @offset: offset inside the block for the page * in the lower bits, it contains flags */ -static size_t save_page_header(RAMState *rs, QEMUFile *f, RAMBlock *block, +static size_t save_page_header(PageSearchStatus *pss, RAMBlock *block, ram_addr_t offset) { size_t size, len; - bool same_block = (block == rs->last_sent_block); + bool same_block = (block == pss->last_sent_block); + QEMUFile *f = pss->pss_channel; if (same_block) { offset |= RAM_SAVE_FLAG_CONTINUE; @@ -699,7 +700,7 @@ static size_t save_page_header(RAMState *rs, QEMUFile *f, RAMBlock *block, qemu_put_byte(f, len); qemu_put_buffer(f, (uint8_t *)block->idstr, len); size += 1 + len; - rs->last_sent_block = block; + pss->last_sent_block = block; } return size; } @@ -783,17 +784,19 @@ static void xbzrle_cache_zero_page(RAMState *rs, ram_addr_t current_addr) * -1 means that xbzrle would be longer than normal * * @rs: current RAM state + * @pss: current PSS channel * @current_data: pointer to the address of the page contents * @current_addr: addr of the page * @block: block that contains the page we want to send * @offset: offset inside the block for the page */ -static int save_xbzrle_page(RAMState *rs, QEMUFile *file, +static int save_xbzrle_page(RAMState *rs, PageSearchStatus *pss, uint8_t **current_data, ram_addr_t current_addr, RAMBlock *block, ram_addr_t offset) { int encoded_len = 0, bytes_xbzrle; uint8_t *prev_cached_page; + QEMUFile *file = pss->pss_channel; if (!cache_is_cached(XBZRLE.cache, current_addr, ram_counters.dirty_sync_count)) { @@ -858,7 +861,7 @@ static int save_xbzrle_page(RAMState *rs, QEMUFile *file, } /* Send XBZRLE based compressed page */ - bytes_xbzrle = save_page_header(rs, file, block, + bytes_xbzrle = save_page_header(pss, block, offset | RAM_SAVE_FLAG_XBZRLE); qemu_put_byte(file, ENCODING_FLAG_XBZRLE); qemu_put_be16(file, encoded_len); @@ -1289,19 +1292,19 @@ static void ram_release_page(const char *rbname, uint64_t offset) * Returns the size of data written to the file, 0 means the page is not * a zero page * - * @rs: current RAM state - * @file: the file where the data is saved + * @pss: current PSS channel * @block: block that contains the page we want to send * @offset: offset inside the block for the page */ -static int save_zero_page_to_file(RAMState *rs, QEMUFile *file, +static int save_zero_page_to_file(PageSearchStatus *pss, RAMBlock *block, ram_addr_t offset) { uint8_t *p = block->host + offset; + QEMUFile *file = pss->pss_channel; int len = 0; if (buffer_is_zero(p, TARGET_PAGE_SIZE)) { - len += save_page_header(rs, file, block, offset | RAM_SAVE_FLAG_ZERO); + len += save_page_header(pss, block, offset | RAM_SAVE_FLAG_ZERO); qemu_put_byte(file, 0); len += 1; ram_release_page(block->idstr, offset); @@ -1314,14 +1317,14 @@ static int save_zero_page_to_file(RAMState *rs, QEMUFile *file, * * Returns the number of pages written. * - * @rs: current RAM state + * @pss: current PSS channel * @block: block that contains the page we want to send * @offset: offset inside the block for the page */ -static int save_zero_page(RAMState *rs, QEMUFile *file, RAMBlock *block, +static int save_zero_page(PageSearchStatus *pss, RAMBlock *block, ram_addr_t offset) { - int len = save_zero_page_to_file(rs, file, block, offset); + int len = save_zero_page_to_file(pss, block, offset); if (len) { qatomic_inc(&ram_counters.duplicate); @@ -1374,16 +1377,18 @@ static bool control_save_page(PageSearchStatus *pss, RAMBlock *block, * * Returns the number of pages written. * - * @rs: current RAM state + * @pss: current PSS channel * @block: block that contains the page we want to send * @offset: offset inside the block for the page * @buf: the page to be sent * @async: send to page asyncly */ -static int save_normal_page(RAMState *rs, QEMUFile *file, RAMBlock *block, +static int save_normal_page(PageSearchStatus *pss, RAMBlock *block, ram_addr_t offset, uint8_t *buf, bool async) { - ram_transferred_add(save_page_header(rs, file, block, + QEMUFile *file = pss->pss_channel; + + ram_transferred_add(save_page_header(pss, block, offset | RAM_SAVE_FLAG_PAGE)); if (async) { qemu_put_buffer_async(file, buf, TARGET_PAGE_SIZE, @@ -1423,7 +1428,7 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss) XBZRLE_cache_lock(); if (rs->xbzrle_enabled && !migration_in_postcopy()) { - pages = save_xbzrle_page(rs, pss->pss_channel, &p, current_addr, + pages = save_xbzrle_page(rs, pss, &p, current_addr, block, offset); if (!rs->last_stage) { /* Can't send this cached data async, since the cache page @@ -1435,8 +1440,7 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss) /* XBZRLE overflow or normal page */ if (pages == -1) { - pages = save_normal_page(rs, pss->pss_channel, block, offset, - p, send_async); + pages = save_normal_page(pss, block, offset, p, send_async); } XBZRLE_cache_unlock(); @@ -1459,14 +1463,15 @@ static bool do_compress_ram_page(QEMUFile *f, z_stream *stream, RAMBlock *block, ram_addr_t offset, uint8_t *source_buf) { RAMState *rs = ram_state; + PageSearchStatus *pss = &rs->pss[RAM_CHANNEL_PRECOPY]; uint8_t *p = block->host + offset; int ret; - if (save_zero_page_to_file(rs, f, block, offset)) { + if (save_zero_page_to_file(pss, block, offset)) { return true; } - save_page_header(rs, f, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE); + save_page_header(pss, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE); /* * copy it to a internal buffer to avoid it being modified by VM @@ -2286,7 +2291,8 @@ static bool save_page_use_compression(RAMState *rs) * has been properly handled by compression, otherwise needs other * paths to handle it */ -static bool save_compress_page(RAMState *rs, RAMBlock *block, ram_addr_t offset) +static bool save_compress_page(RAMState *rs, PageSearchStatus *pss, + RAMBlock *block, ram_addr_t offset) { if (!save_page_use_compression(rs)) { return false; @@ -2302,7 +2308,7 @@ static bool save_compress_page(RAMState *rs, RAMBlock *block, ram_addr_t offset) * We post the fist page as normal page as compression will take * much CPU resource. */ - if (block != rs->last_sent_block) { + if (block != pss->last_sent_block) { flush_compressed_data(rs); return false; } @@ -2333,11 +2339,11 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss) return res; } - if (save_compress_page(rs, block, offset)) { + if (save_compress_page(rs, pss, block, offset)) { return 1; } - res = save_zero_page(rs, pss->pss_channel, block, offset); + res = save_zero_page(pss, block, offset); if (res > 0) { /* Must let xbzrle know, otherwise a previous (now 0'd) cached * page would be stale @@ -2469,7 +2475,7 @@ static void postcopy_preempt_choose_channel(RAMState *rs, PageSearchStatus *pss) * If channel switched, reset last_sent_block since the old sent block * may not be on the same channel. */ - rs->last_sent_block = NULL; + pss->last_sent_block = NULL; trace_postcopy_preempt_switch_channel(channel); } @@ -2804,8 +2810,13 @@ static void ram_save_cleanup(void *opaque) static void ram_state_reset(RAMState *rs) { + int i; + + for (i = 0; i < RAM_CHANNEL_MAX; i++) { + rs->pss[i].last_sent_block = NULL; + } + rs->last_seen_block = NULL; - rs->last_sent_block = NULL; rs->last_page = 0; rs->last_version = ram_list.version; rs->xbzrle_enabled = false; @@ -2999,8 +3010,8 @@ void ram_postcopy_send_discard_bitmap(MigrationState *ms) migration_bitmap_sync(rs); /* Easiest way to make sure we don't resume in the middle of a host-page */ + rs->pss[RAM_CHANNEL_PRECOPY].last_sent_block = NULL; rs->last_seen_block = NULL; - rs->last_sent_block = NULL; rs->last_page = 0; postcopy_each_ram_send_discard(ms);
Since we use PageSearchStatus to represent a channel, it makes perfect sense to keep last_sent_block (aka, leverage RAM_SAVE_FLAG_CONTINUE) to be per-channel rather than global because each channel can be sending different pages on ramblocks. Hence move it from RAMState into PageSearchStatus. Signed-off-by: Peter Xu <peterx@redhat.com> --- migration/ram.c | 71 ++++++++++++++++++++++++++++--------------------- 1 file changed, 41 insertions(+), 30 deletions(-)