| Message ID | 20180313075739.11194-7-xiaoguangrong@tencent.com |
|---|---|
| State | New |
| Headers | show |
| Series | migration: improve and cleanup compression | expand |
* guangrong.xiao@gmail.com (guangrong.xiao@gmail.com) wrote: > From: Xiao Guangrong <xiaoguangrong@tencent.com> > > save_zero_page() is always our first approach to try, move it to > the common place before calling ram_save_compressed_page > and ram_save_page > > Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com> > --- > migration/ram.c | 106 ++++++++++++++++++++++++++++++++------------------------ > 1 file changed, 60 insertions(+), 46 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index 839665d866..9627ce18e9 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1021,15 +1021,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage) > trace_ram_save_page(block->idstr, (uint64_t)offset, p); > > XBZRLE_cache_lock(); > - pages = save_zero_page(rs, block, offset); > - if (pages > 0) { > - /* Must let xbzrle know, otherwise a previous (now 0'd) cached > - * page would be stale > - */ > - xbzrle_cache_zero_page(rs, current_addr); > - ram_release_pages(block->idstr, offset, pages); > - } else if (!rs->ram_bulk_stage && > - !migration_in_postcopy() && migrate_use_xbzrle()) { > + if (!rs->ram_bulk_stage && !migration_in_postcopy() && > + migrate_use_xbzrle()) { > pages = save_xbzrle_page(rs, &p, current_addr, block, > offset, last_stage); > if (!last_stage) { > @@ -1172,40 +1165,23 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss, > > p = block->host + offset; > > - /* When starting the process of a new block, the first page of > - * the block should be sent out before other pages in the same > - * block, and all the pages in last block should have been sent > - * out, keeping this order is important, because the 'cont' flag > - * is used to avoid resending the block name. > - */ > if (block != rs->last_sent_block) { > - flush_compressed_data(rs); > - pages = save_zero_page(rs, block, offset); > - if (pages > 0) { > - ram_release_pages(block->idstr, offset, pages); > - } else { > - /* > - * Make sure the first page is sent out before other pages. > - * > - * we post it as normal page as compression will take much > - * CPU resource. > - */ > - ram_counters.transferred += save_page_header(rs, rs->f, block, > - offset | RAM_SAVE_FLAG_PAGE); > - qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE, > - migrate_release_ram() & > - migration_in_postcopy()); > - ram_counters.transferred += TARGET_PAGE_SIZE; > - ram_counters.normal++; > - pages = 1; > - } > + /* > + * Make sure the first page is sent out before other pages. > + * > + * we post it as normal page as compression will take much > + * CPU resource. > + */ > + ram_counters.transferred += save_page_header(rs, rs->f, block, > + offset | RAM_SAVE_FLAG_PAGE); > + qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE, > + migrate_release_ram() & > + migration_in_postcopy()); > + ram_counters.transferred += TARGET_PAGE_SIZE; > + ram_counters.normal++; > + pages = 1; > } else { > - pages = save_zero_page(rs, block, offset); > - if (pages == -1) { > - pages = compress_page_with_multi_thread(rs, block, offset); > - } else { > - ram_release_pages(block->idstr, offset, pages); > - } > + pages = compress_page_with_multi_thread(rs, block, offset); > } > > return pages; > @@ -1447,6 +1423,25 @@ err: > return -1; > } > > +static bool save_page_use_compression(RAMState *rs) > +{ > + if (!migrate_use_compression()) { > + return false; > + } > + > + /* > + * If xbzrle is on, stop using the data compression after first > + * round of migration even if compression is enabled. In theory, > + * xbzrle can do better than compression. > + */ > + if (rs->ram_bulk_stage || !migrate_use_xbzrle()) { > + return true; > + } > + > + return false; > + > +} > + > /** > * ram_save_target_page: save one target page > * > @@ -1472,12 +1467,31 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss, > } > > /* > - * If xbzrle is on, stop using the data compression after first > - * round of migration even if compression is enabled. In theory, > - * xbzrle can do better than compression. > + * When starting the process of a new block, the first page of > + * the block should be sent out before other pages in the same > + * block, and all the pages in last block should have been sent > + * out, keeping this order is important, because the 'cont' flag > + * is used to avoid resending the block name. > */ > - if (migrate_use_compression() && > - (rs->ram_bulk_stage || !migrate_use_xbzrle())) { > + if (block != rs->last_sent_block && save_page_use_compression(rs)) { > + flush_compressed_data(rs); > + } > + > + res = save_zero_page(rs, block, offset); > + if (res > 0) { > + /* Must let xbzrle know, otherwise a previous (now 0'd) cached > + * page would be stale > + */ > + if (!save_page_use_compression(rs)) { This test is quite interesting; I think the reason it's different in the compression case is that since we don't put any none-0 data in the xbzrle cache, we don't need to knock any old none-0 pages out of the cache. > + XBZRLE_cache_lock(); > + xbzrle_cache_zero_page(rs, block->offset + offset); > + XBZRLE_cache_unlock(); > + } > + ram_release_pages(block->idstr, offset, res); > + goto page_saved; > + } > + > + if (save_page_use_compression(rs)) { > res = ram_save_compressed_page(rs, pss, last_stage); > } else { > res = ram_save_page(rs, pss, last_stage); Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > -- > 2.14.3 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Tue, Mar 13, 2018 at 03:57:37PM +0800, guangrong.xiao@gmail.com wrote: > From: Xiao Guangrong <xiaoguangrong@tencent.com> > > save_zero_page() is always our first approach to try, move it to > the common place before calling ram_save_compressed_page > and ram_save_page > > Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com> > --- > migration/ram.c | 106 ++++++++++++++++++++++++++++++++------------------------ > 1 file changed, 60 insertions(+), 46 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index 839665d866..9627ce18e9 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1021,15 +1021,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage) > trace_ram_save_page(block->idstr, (uint64_t)offset, p); > > XBZRLE_cache_lock(); > - pages = save_zero_page(rs, block, offset); > - if (pages > 0) { > - /* Must let xbzrle know, otherwise a previous (now 0'd) cached > - * page would be stale > - */ > - xbzrle_cache_zero_page(rs, current_addr); > - ram_release_pages(block->idstr, offset, pages); > - } else if (!rs->ram_bulk_stage && > - !migration_in_postcopy() && migrate_use_xbzrle()) { > + if (!rs->ram_bulk_stage && !migration_in_postcopy() && > + migrate_use_xbzrle()) { Nit: indent problem? [...] > +static bool save_page_use_compression(RAMState *rs) > +{ > + if (!migrate_use_compression()) { > + return false; > + } > + > + /* > + * If xbzrle is on, stop using the data compression after first > + * round of migration even if compression is enabled. In theory, > + * xbzrle can do better than compression. > + */ > + if (rs->ram_bulk_stage || !migrate_use_xbzrle()) { > + return true; > + } > + > + return false; > + Nit: remove this line? Otherwise I'd say I like this patch... :) Better with the nit fixed: Reviewed-by: Peter Xu <peterx@redhat.com> Thanks,
diff --git a/migration/ram.c b/migration/ram.c index 839665d866..9627ce18e9 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1021,15 +1021,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage) trace_ram_save_page(block->idstr, (uint64_t)offset, p); XBZRLE_cache_lock(); - pages = save_zero_page(rs, block, offset); - if (pages > 0) { - /* Must let xbzrle know, otherwise a previous (now 0'd) cached - * page would be stale - */ - xbzrle_cache_zero_page(rs, current_addr); - ram_release_pages(block->idstr, offset, pages); - } else if (!rs->ram_bulk_stage && - !migration_in_postcopy() && migrate_use_xbzrle()) { + if (!rs->ram_bulk_stage && !migration_in_postcopy() && + migrate_use_xbzrle()) { pages = save_xbzrle_page(rs, &p, current_addr, block, offset, last_stage); if (!last_stage) { @@ -1172,40 +1165,23 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss, p = block->host + offset; - /* When starting the process of a new block, the first page of - * the block should be sent out before other pages in the same - * block, and all the pages in last block should have been sent - * out, keeping this order is important, because the 'cont' flag - * is used to avoid resending the block name. - */ if (block != rs->last_sent_block) { - flush_compressed_data(rs); - pages = save_zero_page(rs, block, offset); - if (pages > 0) { - ram_release_pages(block->idstr, offset, pages); - } else { - /* - * Make sure the first page is sent out before other pages. - * - * we post it as normal page as compression will take much - * CPU resource. - */ - ram_counters.transferred += save_page_header(rs, rs->f, block, - offset | RAM_SAVE_FLAG_PAGE); - qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE, - migrate_release_ram() & - migration_in_postcopy()); - ram_counters.transferred += TARGET_PAGE_SIZE; - ram_counters.normal++; - pages = 1; - } + /* + * Make sure the first page is sent out before other pages. + * + * we post it as normal page as compression will take much + * CPU resource. + */ + ram_counters.transferred += save_page_header(rs, rs->f, block, + offset | RAM_SAVE_FLAG_PAGE); + qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE, + migrate_release_ram() & + migration_in_postcopy()); + ram_counters.transferred += TARGET_PAGE_SIZE; + ram_counters.normal++; + pages = 1; } else { - pages = save_zero_page(rs, block, offset); - if (pages == -1) { - pages = compress_page_with_multi_thread(rs, block, offset); - } else { - ram_release_pages(block->idstr, offset, pages); - } + pages = compress_page_with_multi_thread(rs, block, offset); } return pages; @@ -1447,6 +1423,25 @@ err: return -1; } +static bool save_page_use_compression(RAMState *rs) +{ + if (!migrate_use_compression()) { + return false; + } + + /* + * If xbzrle is on, stop using the data compression after first + * round of migration even if compression is enabled. In theory, + * xbzrle can do better than compression. + */ + if (rs->ram_bulk_stage || !migrate_use_xbzrle()) { + return true; + } + + return false; + +} + /** * ram_save_target_page: save one target page * @@ -1472,12 +1467,31 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss, } /* - * If xbzrle is on, stop using the data compression after first - * round of migration even if compression is enabled. In theory, - * xbzrle can do better than compression. + * When starting the process of a new block, the first page of + * the block should be sent out before other pages in the same + * block, and all the pages in last block should have been sent + * out, keeping this order is important, because the 'cont' flag + * is used to avoid resending the block name. */ - if (migrate_use_compression() && - (rs->ram_bulk_stage || !migrate_use_xbzrle())) { + if (block != rs->last_sent_block && save_page_use_compression(rs)) { + flush_compressed_data(rs); + } + + res = save_zero_page(rs, block, offset); + if (res > 0) { + /* Must let xbzrle know, otherwise a previous (now 0'd) cached + * page would be stale + */ + if (!save_page_use_compression(rs)) { + XBZRLE_cache_lock(); + xbzrle_cache_zero_page(rs, block->offset + offset); + XBZRLE_cache_unlock(); + } + ram_release_pages(block->idstr, offset, res); + goto page_saved; + } + + if (save_page_use_compression(rs)) { res = ram_save_compressed_page(rs, pss, last_stage); } else { res = ram_save_page(rs, pss, last_stage);