| Message ID | 20190819061843.28642-3-richardw.yang@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | migration/postcopy: unsentmap is not necessary | expand |
* Wei Yang (richardw.yang@linux.intel.com) wrote: > Commit f3f491fcd6dd594ba695 ('Postcopy: Maintain unsentmap') introduced > unsentmap to track not yet sent pages. > > This is not necessary since: > > * unsentmap is a sub-set of bmap before postcopy start > * unsentmap is the summation of bmap and unsentmap after canonicalizing > > This patch just removes it. > > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Yes, that's simpler Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > include/exec/ram_addr.h | 6 ---- > migration/ram.c | 80 ++++++++--------------------------------- > 2 files changed, 14 insertions(+), 72 deletions(-) > > diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h > index a327a80cfe..e96e621de5 100644 > --- a/include/exec/ram_addr.h > +++ b/include/exec/ram_addr.h > @@ -44,12 +44,6 @@ struct RAMBlock { > size_t page_size; > /* dirty bitmap used during migration */ > unsigned long *bmap; > - /* bitmap of pages that haven't been sent even once > - * only maintained and used in postcopy at the moment > - * where it's used to send the dirtymap at the start > - * of the postcopy phase > - */ > - unsigned long *unsentmap; > /* bitmap of already received pages in postcopy */ > unsigned long *receivedmap; > > diff --git a/migration/ram.c b/migration/ram.c > index 075ddc468c..066eb4755f 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -2348,7 +2348,7 @@ static bool get_queued_page(RAMState *rs, PageSearchStatus *pss) > dirty = test_bit(page, block->bmap); > if (!dirty) { > trace_get_queued_page_not_dirty(block->idstr, (uint64_t)offset, > - page, test_bit(page, block->unsentmap)); > + page, test_bit(page, block->bmap)); We could actually lose that last trace parameter. Dave > } else { > trace_get_queued_page(block->idstr, (uint64_t)offset, page); > } > @@ -2619,10 +2619,6 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss, > } > > pages += tmppages; > - if (pss->block->unsentmap) { > - clear_bit(pss->page, pss->block->unsentmap); > - } > - > pss->page++; > } while ((pss->page & (pagesize_bits - 1)) && > offset_in_ramblock(pss->block, pss->page << TARGET_PAGE_BITS)); > @@ -2776,8 +2772,6 @@ static void ram_save_cleanup(void *opaque) > block->clear_bmap = NULL; > g_free(block->bmap); > block->bmap = NULL; > - g_free(block->unsentmap); > - block->unsentmap = NULL; > } > > xbzrle_cleanup(); > @@ -2857,8 +2851,6 @@ void ram_postcopy_migrated_memory_release(MigrationState *ms) > * Returns zero on success > * > * Callback from postcopy_each_ram_send_discard for each RAMBlock > - * Note: At this point the 'unsentmap' is the processed bitmap combined > - * with the dirtymap; so a '1' means it's either dirty or unsent. > * > * @ms: current migration state > * @block: RAMBlock to discard > @@ -2867,17 +2859,17 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms, RAMBlock *block) > { > unsigned long end = block->used_length >> TARGET_PAGE_BITS; > unsigned long current; > - unsigned long *unsentmap = block->unsentmap; > + unsigned long *bitmap = block->bmap; > > for (current = 0; current < end; ) { > - unsigned long one = find_next_bit(unsentmap, end, current); > + unsigned long one = find_next_bit(bitmap, end, current); > unsigned long zero, discard_length; > > if (one >= end) { > break; > } > > - zero = find_next_zero_bit(unsentmap, end, one + 1); > + zero = find_next_zero_bit(bitmap, end, one + 1); > > if (zero >= end) { > discard_length = end - one; > @@ -2938,16 +2930,12 @@ static int postcopy_each_ram_send_discard(MigrationState *ms) > * clean, not a mix. This function canonicalizes the bitmaps. > * > * @ms: current migration state > - * @unsent_pass: if true we need to canonicalize partially unsent host pages > - * otherwise we need to canonicalize partially dirty host pages > * @block: block that contains the page we want to canonicalize > */ > -static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, > - RAMBlock *block) > +static void postcopy_chunk_hostpages_pass(MigrationState *ms, RAMBlock *block) > { > RAMState *rs = ram_state; > unsigned long *bitmap = block->bmap; > - unsigned long *unsentmap = block->unsentmap; > unsigned int host_ratio = block->page_size / TARGET_PAGE_SIZE; > unsigned long pages = block->used_length >> TARGET_PAGE_BITS; > unsigned long run_start; > @@ -2957,13 +2945,8 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, > return; > } > > - if (unsent_pass) { > - /* Find a sent page */ > - run_start = find_next_zero_bit(unsentmap, pages, 0); > - } else { > - /* Find a dirty page */ > - run_start = find_next_bit(bitmap, pages, 0); > - } > + /* Find a dirty page */ > + run_start = find_next_bit(bitmap, pages, 0); > > while (run_start < pages) { > > @@ -2973,11 +2956,7 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, > */ > if (QEMU_IS_ALIGNED(run_start, host_ratio)) { > /* Find the end of this run */ > - if (unsent_pass) { > - run_start = find_next_bit(unsentmap, pages, run_start + 1); > - } else { > - run_start = find_next_zero_bit(bitmap, pages, run_start + 1); > - } > + run_start = find_next_zero_bit(bitmap, pages, run_start + 1); > /* > * If the end isn't at the start of a host page, then the > * run doesn't finish at the end of a host page > @@ -2994,9 +2973,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, > /* Clean up the bitmap */ > for (page = fixup_start_addr; > page < fixup_start_addr + host_ratio; page++) { > - /* All pages in this host page are now not sent */ > - set_bit(page, unsentmap); > - > /* > * Remark them as dirty, updating the count for any pages > * that weren't previously dirty. > @@ -3005,13 +2981,8 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, > } > } > > - if (unsent_pass) { > - /* Find the next sent page for the next iteration */ > - run_start = find_next_zero_bit(unsentmap, pages, run_start); > - } else { > - /* Find the next dirty page for the next iteration */ > - run_start = find_next_bit(bitmap, pages, run_start); > - } > + /* Find the next dirty page for the next iteration */ > + run_start = find_next_bit(bitmap, pages, run_start); > } > } > > @@ -3033,13 +3004,10 @@ static int postcopy_chunk_hostpages(MigrationState *ms, RAMBlock *block) > { > postcopy_discard_send_init(ms, block->idstr); > > - /* First pass: Discard all partially sent host pages */ > - postcopy_chunk_hostpages_pass(ms, true, block); > /* > - * Second pass: Ensure that all partially dirty host pages are made > - * fully dirty. > + * Ensure that all partially dirty host pages are made fully dirty. > */ > - postcopy_chunk_hostpages_pass(ms, false, block); > + postcopy_chunk_hostpages_pass(ms, block); > > postcopy_discard_send_finish(ms); > return 0; > @@ -3077,19 +3045,6 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms) > rs->last_page = 0; > > RAMBLOCK_FOREACH_NOT_IGNORED(block) { > - unsigned long pages = block->used_length >> TARGET_PAGE_BITS; > - unsigned long *bitmap = block->bmap; > - unsigned long *unsentmap = block->unsentmap; > - > - if (!unsentmap) { > - /* We don't have a safe way to resize the sentmap, so > - * if the bitmap was resized it will be NULL at this > - * point. > - */ > - error_report("migration ram resized during precopy phase"); > - rcu_read_unlock(); > - return -EINVAL; > - } > /* Deal with TPS != HPS and huge pages */ > ret = postcopy_chunk_hostpages(ms, block); > if (ret) { > @@ -3097,12 +3052,9 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms) > return ret; > } > > - /* > - * Update the unsentmap to be unsentmap = unsentmap | dirty > - */ > - bitmap_or(unsentmap, unsentmap, bitmap, pages); > #ifdef DEBUG_POSTCOPY > - ram_debug_dump_bitmap(unsentmap, true, pages); > + ram_debug_dump_bitmap(block->bmap, true, > + block->used_length >> TARGET_PAGE_BITS); > #endif > } > trace_ram_postcopy_send_discard_bitmap(); > @@ -3270,10 +3222,6 @@ static void ram_list_init_bitmaps(void) > bitmap_set(block->bmap, 0, pages); > block->clear_bmap_shift = shift; > block->clear_bmap = bitmap_new(clear_bmap_size(pages, shift)); > - if (migrate_postcopy_ram()) { > - block->unsentmap = bitmap_new(pages); > - bitmap_set(block->unsentmap, 0, pages); > - } > } > } > } > -- > 2.17.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index a327a80cfe..e96e621de5 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -44,12 +44,6 @@ struct RAMBlock { size_t page_size; /* dirty bitmap used during migration */ unsigned long *bmap; - /* bitmap of pages that haven't been sent even once - * only maintained and used in postcopy at the moment - * where it's used to send the dirtymap at the start - * of the postcopy phase - */ - unsigned long *unsentmap; /* bitmap of already received pages in postcopy */ unsigned long *receivedmap; diff --git a/migration/ram.c b/migration/ram.c index 075ddc468c..066eb4755f 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2348,7 +2348,7 @@ static bool get_queued_page(RAMState *rs, PageSearchStatus *pss) dirty = test_bit(page, block->bmap); if (!dirty) { trace_get_queued_page_not_dirty(block->idstr, (uint64_t)offset, - page, test_bit(page, block->unsentmap)); + page, test_bit(page, block->bmap)); } else { trace_get_queued_page(block->idstr, (uint64_t)offset, page); } @@ -2619,10 +2619,6 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss, } pages += tmppages; - if (pss->block->unsentmap) { - clear_bit(pss->page, pss->block->unsentmap); - } - pss->page++; } while ((pss->page & (pagesize_bits - 1)) && offset_in_ramblock(pss->block, pss->page << TARGET_PAGE_BITS)); @@ -2776,8 +2772,6 @@ static void ram_save_cleanup(void *opaque) block->clear_bmap = NULL; g_free(block->bmap); block->bmap = NULL; - g_free(block->unsentmap); - block->unsentmap = NULL; } xbzrle_cleanup(); @@ -2857,8 +2851,6 @@ void ram_postcopy_migrated_memory_release(MigrationState *ms) * Returns zero on success * * Callback from postcopy_each_ram_send_discard for each RAMBlock - * Note: At this point the 'unsentmap' is the processed bitmap combined - * with the dirtymap; so a '1' means it's either dirty or unsent. * * @ms: current migration state * @block: RAMBlock to discard @@ -2867,17 +2859,17 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms, RAMBlock *block) { unsigned long end = block->used_length >> TARGET_PAGE_BITS; unsigned long current; - unsigned long *unsentmap = block->unsentmap; + unsigned long *bitmap = block->bmap; for (current = 0; current < end; ) { - unsigned long one = find_next_bit(unsentmap, end, current); + unsigned long one = find_next_bit(bitmap, end, current); unsigned long zero, discard_length; if (one >= end) { break; } - zero = find_next_zero_bit(unsentmap, end, one + 1); + zero = find_next_zero_bit(bitmap, end, one + 1); if (zero >= end) { discard_length = end - one; @@ -2938,16 +2930,12 @@ static int postcopy_each_ram_send_discard(MigrationState *ms) * clean, not a mix. This function canonicalizes the bitmaps. * * @ms: current migration state - * @unsent_pass: if true we need to canonicalize partially unsent host pages - * otherwise we need to canonicalize partially dirty host pages * @block: block that contains the page we want to canonicalize */ -static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, - RAMBlock *block) +static void postcopy_chunk_hostpages_pass(MigrationState *ms, RAMBlock *block) { RAMState *rs = ram_state; unsigned long *bitmap = block->bmap; - unsigned long *unsentmap = block->unsentmap; unsigned int host_ratio = block->page_size / TARGET_PAGE_SIZE; unsigned long pages = block->used_length >> TARGET_PAGE_BITS; unsigned long run_start; @@ -2957,13 +2945,8 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, return; } - if (unsent_pass) { - /* Find a sent page */ - run_start = find_next_zero_bit(unsentmap, pages, 0); - } else { - /* Find a dirty page */ - run_start = find_next_bit(bitmap, pages, 0); - } + /* Find a dirty page */ + run_start = find_next_bit(bitmap, pages, 0); while (run_start < pages) { @@ -2973,11 +2956,7 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, */ if (QEMU_IS_ALIGNED(run_start, host_ratio)) { /* Find the end of this run */ - if (unsent_pass) { - run_start = find_next_bit(unsentmap, pages, run_start + 1); - } else { - run_start = find_next_zero_bit(bitmap, pages, run_start + 1); - } + run_start = find_next_zero_bit(bitmap, pages, run_start + 1); /* * If the end isn't at the start of a host page, then the * run doesn't finish at the end of a host page @@ -2994,9 +2973,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, /* Clean up the bitmap */ for (page = fixup_start_addr; page < fixup_start_addr + host_ratio; page++) { - /* All pages in this host page are now not sent */ - set_bit(page, unsentmap); - /* * Remark them as dirty, updating the count for any pages * that weren't previously dirty. @@ -3005,13 +2981,8 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass, } } - if (unsent_pass) { - /* Find the next sent page for the next iteration */ - run_start = find_next_zero_bit(unsentmap, pages, run_start); - } else { - /* Find the next dirty page for the next iteration */ - run_start = find_next_bit(bitmap, pages, run_start); - } + /* Find the next dirty page for the next iteration */ + run_start = find_next_bit(bitmap, pages, run_start); } } @@ -3033,13 +3004,10 @@ static int postcopy_chunk_hostpages(MigrationState *ms, RAMBlock *block) { postcopy_discard_send_init(ms, block->idstr); - /* First pass: Discard all partially sent host pages */ - postcopy_chunk_hostpages_pass(ms, true, block); /* - * Second pass: Ensure that all partially dirty host pages are made - * fully dirty. + * Ensure that all partially dirty host pages are made fully dirty. */ - postcopy_chunk_hostpages_pass(ms, false, block); + postcopy_chunk_hostpages_pass(ms, block); postcopy_discard_send_finish(ms); return 0; @@ -3077,19 +3045,6 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms) rs->last_page = 0; RAMBLOCK_FOREACH_NOT_IGNORED(block) { - unsigned long pages = block->used_length >> TARGET_PAGE_BITS; - unsigned long *bitmap = block->bmap; - unsigned long *unsentmap = block->unsentmap; - - if (!unsentmap) { - /* We don't have a safe way to resize the sentmap, so - * if the bitmap was resized it will be NULL at this - * point. - */ - error_report("migration ram resized during precopy phase"); - rcu_read_unlock(); - return -EINVAL; - } /* Deal with TPS != HPS and huge pages */ ret = postcopy_chunk_hostpages(ms, block); if (ret) { @@ -3097,12 +3052,9 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms) return ret; } - /* - * Update the unsentmap to be unsentmap = unsentmap | dirty - */ - bitmap_or(unsentmap, unsentmap, bitmap, pages); #ifdef DEBUG_POSTCOPY - ram_debug_dump_bitmap(unsentmap, true, pages); + ram_debug_dump_bitmap(block->bmap, true, + block->used_length >> TARGET_PAGE_BITS); #endif } trace_ram_postcopy_send_discard_bitmap(); @@ -3270,10 +3222,6 @@ static void ram_list_init_bitmaps(void) bitmap_set(block->bmap, 0, pages); block->clear_bmap_shift = shift; block->clear_bmap = bitmap_new(clear_bmap_size(pages, shift)); - if (migrate_postcopy_ram()) { - block->unsentmap = bitmap_new(pages); - bitmap_set(block->unsentmap, 0, pages); - } } } }
Commit f3f491fcd6dd594ba695 ('Postcopy: Maintain unsentmap') introduced unsentmap to track not yet sent pages. This is not necessary since: * unsentmap is a sub-set of bmap before postcopy start * unsentmap is the summation of bmap and unsentmap after canonicalizing This patch just removes it. Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> --- include/exec/ram_addr.h | 6 ---- migration/ram.c | 80 ++++++++--------------------------------- 2 files changed, 14 insertions(+), 72 deletions(-)