* Juan Quintela (quint...@redhat.com) wrote: > Hi > > (Li special edition) > > Current migration code returns number of bytes transferred and from > there we decide if we.have sent something or not. Problem, we need > two results: number of pages written, and number of bytes written > (depending on compression, zero pages, etc, it is not possible to > derive one value from the other). > > So, I changed all relevant function to return the number of written > pages, and then pass as uint64_t *bytes_transferred to update the > written bytes. > > On current code, makes things a bit easier to understand, but is not > strictely necesary. But for the compression patches from Li, it makes > a big difference, we can return that we have written a page, even if > we have just started the write, but having writtten in reality zero > bytes. > > Once there, I add doxygen documentation to all function that I touched > (yes, I was long due). > > save_block_hdr really saved headers for pages, not blocks. Rename it, > and simplify the interface. > > Li, does this make your life easier? I hope so. Should make really > easy to remove the one_bytes_sent "hack", and allow my other suggestions. > > Comments?
I like it; it generally seems to make sense to separate the concept of whether we've actually sent any pages from the actual byte counting. While you're there though; do we actually care about bean counting the individual header bytes? For example the &bytes_transferred += 1 in the RAM_SAVE_FLAG_COMPRESS case where it puts the 0, or the EOS mark where we add 8 bytes? Do we need to keep track of anything other than stuff that's potentially big enough to make an impact on the bandwidth calculations? Dave > > Later, Juan. > > PD. Code is obviously correct, but I run it through virt-test > anyways. And it failed :-( In despair, I tried virt-test on HEAD, > and it also failed, so .... I add another thing to my ToDo list. > > PD2. Modifying ram_save_page() has become complicated, very > complicated. I think that know a couple of simplications, but > require touching RDMA code, and anyways, fixing migration in > "master" looks like a higher priority. > > > Juan Quintela (6): > ram: make all save_page functions take a uint64_t parameter > ram_find_and_save_block: change calling convention > ram_save_page: change calling covention > save_xbzrle_page: change calling convention > save_block_hdr: we can recalculate the cont parameter here > rename save_block_hdr to save_page_header > > arch_init.c | 176 > ++++++++++++++++++++++++++---------------- > include/migration/migration.h | 2 +- > include/migration/qemu-file.h | 2 +- > migration/qemu-file.c | 3 +- > migration/rdma.c | 2 +- > 5 files changed, 114 insertions(+), 71 deletions(-) > > -- > 2.1.0 > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
