* [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary
@ 2019-08-19 6:18 Wei Yang
2019-08-19 6:18 ` [Qemu-devel] [PATCH 1/3] migration/postcopy: not necessary to do discard when canonicalizing bitmap Wei Yang
` (4 more replies)
0 siblings, 5 replies; 12+ messages in thread
From: Wei Yang @ 2019-08-19 6:18 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, Wei Yang, dgilbert, quintela
Three patches to cleanup postcopy:
[1]: split canonicalize bitmap and discard page
[2]: remove unsentmap since it is not necessary
[3]: cleanup the get_queued_page_not_dirty
Wei Yang (3):
migration/postcopy: not necessary to do discard when canonicalizing
bitmap
migration/postcopy: unsentmap is not necessary for postcopy
migration: remove sent parameter in get_queued_page_not_dirty
include/exec/ram_addr.h | 6 ---
migration/ram.c | 94 +++++++----------------------------------
migration/trace-events | 2 +-
3 files changed, 16 insertions(+), 86 deletions(-)
--
2.17.1
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Qemu-devel] [PATCH 1/3] migration/postcopy: not necessary to do discard when canonicalizing bitmap
2019-08-19 6:18 [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
@ 2019-08-19 6:18 ` Wei Yang
2019-09-24 10:02 ` Dr. David Alan Gilbert
2019-08-19 6:18 ` [Qemu-devel] [PATCH 2/3] migration/postcopy: unsentmap is not necessary for postcopy Wei Yang
` (3 subsequent siblings)
4 siblings, 1 reply; 12+ messages in thread
From: Wei Yang @ 2019-08-19 6:18 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, Wei Yang, dgilbert, quintela
All pages, either partially sent or partially dirty, will be discarded in
postcopy_send_discard_bm_ram(), since we update the unsentmap to be
unsentmap = unsentmap | dirty in ram_postcopy_send_discard_bitmap().
This is not necessary to do discard when canonicalizing bitmap. And by
doing so, we separate the page discard into two individual steps:
* canonicalize bitmap
* discard page
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
migration/ram.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 35552c090b..075ddc468c 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2928,7 +2928,7 @@ static int postcopy_each_ram_send_discard(MigrationState *ms)
}
/**
- * postcopy_chunk_hostpages_pass: canocalize bitmap in hostpages
+ * postcopy_chunk_hostpages_pass: canonicalize bitmap in hostpages
*
* Helper for postcopy_chunk_hostpages; it's called twice to
* canonicalize the two bitmaps, that are similar, but one is
@@ -2991,18 +2991,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
host_ratio);
run_start = QEMU_ALIGN_UP(run_start, host_ratio);
- /* Tell the destination to discard this page */
- if (unsent_pass || !test_bit(fixup_start_addr, unsentmap)) {
- /* For the unsent_pass we:
- * discard partially sent pages
- * For the !unsent_pass (dirty) we:
- * discard partially dirty pages that were sent
- * (any partially sent pages were already discarded
- * by the previous unsent_pass)
- */
- postcopy_discard_send_range(ms, fixup_start_addr, host_ratio);
- }
-
/* Clean up the bitmap */
for (page = fixup_start_addr;
page < fixup_start_addr + host_ratio; page++) {
--
2.17.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [Qemu-devel] [PATCH 2/3] migration/postcopy: unsentmap is not necessary for postcopy
2019-08-19 6:18 [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
2019-08-19 6:18 ` [Qemu-devel] [PATCH 1/3] migration/postcopy: not necessary to do discard when canonicalizing bitmap Wei Yang
@ 2019-08-19 6:18 ` Wei Yang
2019-09-24 10:18 ` Dr. David Alan Gilbert
2019-08-19 6:18 ` [Qemu-devel] [PATCH 3/3] migration: remove sent parameter in get_queued_page_not_dirty Wei Yang
` (2 subsequent siblings)
4 siblings, 1 reply; 12+ messages in thread
From: Wei Yang @ 2019-08-19 6:18 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, Wei Yang, dgilbert, quintela
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(-)
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);
- }
}
}
}
--
2.17.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [Qemu-devel] [PATCH 3/3] migration: remove sent parameter in get_queued_page_not_dirty
2019-08-19 6:18 [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
2019-08-19 6:18 ` [Qemu-devel] [PATCH 1/3] migration/postcopy: not necessary to do discard when canonicalizing bitmap Wei Yang
2019-08-19 6:18 ` [Qemu-devel] [PATCH 2/3] migration/postcopy: unsentmap is not necessary for postcopy Wei Yang
@ 2019-08-19 6:18 ` Wei Yang
2019-09-24 10:19 ` Dr. David Alan Gilbert
2019-09-16 6:06 ` [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
2019-09-25 9:52 ` [Qemu-devel] " Dr. David Alan Gilbert
4 siblings, 1 reply; 12+ messages in thread
From: Wei Yang @ 2019-08-19 6:18 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, Wei Yang, dgilbert, quintela
This is a cleanup for previous removal of unsentmap.
The sent parameter is not necessary now.
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
migration/ram.c | 2 +-
migration/trace-events | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 066eb4755f..a6d3d09ebd 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->bmap));
+ page);
} else {
trace_get_queued_page(block->idstr, (uint64_t)offset, page);
}
diff --git a/migration/trace-events b/migration/trace-events
index 00ffcd5930..858d415d56 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -76,7 +76,7 @@ qemu_file_fclose(void) ""
# ram.c
get_queued_page(const char *block_name, uint64_t tmp_offset, unsigned long page_abs) "%s/0x%" PRIx64 " page_abs=0x%lx"
-get_queued_page_not_dirty(const char *block_name, uint64_t tmp_offset, unsigned long page_abs, int sent) "%s/0x%" PRIx64 " page_abs=0x%lx (sent=%d)"
+get_queued_page_not_dirty(const char *block_name, uint64_t tmp_offset, unsigned long page_abs) "%s/0x%" PRIx64 " page_abs=0x%lx"
migration_bitmap_sync_start(void) ""
migration_bitmap_sync_end(uint64_t dirty_pages) "dirty_pages %" PRIu64
migration_bitmap_clear_dirty(char *str, uint64_t start, uint64_t size, unsigned long page) "rb %s start 0x%"PRIx64" size 0x%"PRIx64" page 0x%lx"
--
2.17.1
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary
2019-08-19 6:18 [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
` (2 preceding siblings ...)
2019-08-19 6:18 ` [Qemu-devel] [PATCH 3/3] migration: remove sent parameter in get_queued_page_not_dirty Wei Yang
@ 2019-09-16 6:06 ` Wei Yang
2019-09-20 18:53 ` Dr. David Alan Gilbert
2019-09-25 9:52 ` [Qemu-devel] " Dr. David Alan Gilbert
4 siblings, 1 reply; 12+ messages in thread
From: Wei Yang @ 2019-09-16 6:06 UTC (permalink / raw)
To: Wei Yang; +Cc: pbonzini, qemu-devel, dgilbert, quintela
Hi, Dave and Juan
Would you mind taking a look at this one?
On Mon, Aug 19, 2019 at 02:18:40PM +0800, Wei Yang wrote:
>Three patches to cleanup postcopy:
>
>[1]: split canonicalize bitmap and discard page
>[2]: remove unsentmap since it is not necessary
>[3]: cleanup the get_queued_page_not_dirty
>
>Wei Yang (3):
> migration/postcopy: not necessary to do discard when canonicalizing
> bitmap
> migration/postcopy: unsentmap is not necessary for postcopy
> migration: remove sent parameter in get_queued_page_not_dirty
>
> include/exec/ram_addr.h | 6 ---
> migration/ram.c | 94 +++++++----------------------------------
> migration/trace-events | 2 +-
> 3 files changed, 16 insertions(+), 86 deletions(-)
>
>--
>2.17.1
--
Wei Yang
Help you, Help me
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 0/3] migration/postcopy: unsentmap is not necessary
2019-09-16 6:06 ` [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
@ 2019-09-20 18:53 ` Dr. David Alan Gilbert
2019-09-23 5:56 ` Wei Yang
0 siblings, 1 reply; 12+ messages in thread
From: Dr. David Alan Gilbert @ 2019-09-20 18:53 UTC (permalink / raw)
To: Wei Yang; +Cc: pbonzini, qemu-devel, quintela
* Wei Yang (richardw.yang@linux.intel.com) wrote:
> Hi, Dave and Juan
>
> Would you mind taking a look at this one?
Yes, I'll have a look, I'm just fighting through a bunch of other stuff.
Dave
> On Mon, Aug 19, 2019 at 02:18:40PM +0800, Wei Yang wrote:
> >Three patches to cleanup postcopy:
> >
> >[1]: split canonicalize bitmap and discard page
> >[2]: remove unsentmap since it is not necessary
> >[3]: cleanup the get_queued_page_not_dirty
> >
> >Wei Yang (3):
> > migration/postcopy: not necessary to do discard when canonicalizing
> > bitmap
> > migration/postcopy: unsentmap is not necessary for postcopy
> > migration: remove sent parameter in get_queued_page_not_dirty
> >
> > include/exec/ram_addr.h | 6 ---
> > migration/ram.c | 94 +++++++----------------------------------
> > migration/trace-events | 2 +-
> > 3 files changed, 16 insertions(+), 86 deletions(-)
> >
> >--
> >2.17.1
>
> --
> Wei Yang
> Help you, Help me
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 0/3] migration/postcopy: unsentmap is not necessary
2019-09-20 18:53 ` Dr. David Alan Gilbert
@ 2019-09-23 5:56 ` Wei Yang
0 siblings, 0 replies; 12+ messages in thread
From: Wei Yang @ 2019-09-23 5:56 UTC (permalink / raw)
To: Dr. David Alan Gilbert; +Cc: pbonzini, quintela, Wei Yang, qemu-devel
On Fri, Sep 20, 2019 at 07:53:51PM +0100, Dr. David Alan Gilbert wrote:
>* Wei Yang (richardw.yang@linux.intel.com) wrote:
>> Hi, Dave and Juan
>>
>> Would you mind taking a look at this one?
>
>Yes, I'll have a look, I'm just fighting through a bunch of other stuff.
>
Yep, thanks ~ Me too :-)
Have a good day
>Dave
>
>> On Mon, Aug 19, 2019 at 02:18:40PM +0800, Wei Yang wrote:
>> >Three patches to cleanup postcopy:
>> >
>> >[1]: split canonicalize bitmap and discard page
>> >[2]: remove unsentmap since it is not necessary
>> >[3]: cleanup the get_queued_page_not_dirty
>> >
>> >Wei Yang (3):
>> > migration/postcopy: not necessary to do discard when canonicalizing
>> > bitmap
>> > migration/postcopy: unsentmap is not necessary for postcopy
>> > migration: remove sent parameter in get_queued_page_not_dirty
>> >
>> > include/exec/ram_addr.h | 6 ---
>> > migration/ram.c | 94 +++++++----------------------------------
>> > migration/trace-events | 2 +-
>> > 3 files changed, 16 insertions(+), 86 deletions(-)
>> >
>> >--
>> >2.17.1
>>
>> --
>> Wei Yang
>> Help you, Help me
>--
>Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
--
Wei Yang
Help you, Help me
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 1/3] migration/postcopy: not necessary to do discard when canonicalizing bitmap
2019-08-19 6:18 ` [Qemu-devel] [PATCH 1/3] migration/postcopy: not necessary to do discard when canonicalizing bitmap Wei Yang
@ 2019-09-24 10:02 ` Dr. David Alan Gilbert
2019-09-25 0:25 ` Wei Yang
0 siblings, 1 reply; 12+ messages in thread
From: Dr. David Alan Gilbert @ 2019-09-24 10:02 UTC (permalink / raw)
To: Wei Yang; +Cc: pbonzini, qemu-devel, quintela
* Wei Yang (richardw.yang@linux.intel.com) wrote:
> All pages, either partially sent or partially dirty, will be discarded in
> postcopy_send_discard_bm_ram(), since we update the unsentmap to be
> unsentmap = unsentmap | dirty in ram_postcopy_send_discard_bitmap().
>
> This is not necessary to do discard when canonicalizing bitmap. And by
> doing so, we separate the page discard into two individual steps:
>
> * canonicalize bitmap
> * discard page
>
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Yes, I think when I originally wrote it, the set of pages that was
discarded was different; I think it was actually the set of
!unsent & dirty - i.e. only pages that had been sent and then redirtied;
it later got reworked to include unsent pages as well - so this lot can
be simplified.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> migration/ram.c | 14 +-------------
> 1 file changed, 1 insertion(+), 13 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 35552c090b..075ddc468c 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2928,7 +2928,7 @@ static int postcopy_each_ram_send_discard(MigrationState *ms)
> }
>
> /**
> - * postcopy_chunk_hostpages_pass: canocalize bitmap in hostpages
> + * postcopy_chunk_hostpages_pass: canonicalize bitmap in hostpages
> *
> * Helper for postcopy_chunk_hostpages; it's called twice to
> * canonicalize the two bitmaps, that are similar, but one is
> @@ -2991,18 +2991,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
> host_ratio);
> run_start = QEMU_ALIGN_UP(run_start, host_ratio);
>
> - /* Tell the destination to discard this page */
> - if (unsent_pass || !test_bit(fixup_start_addr, unsentmap)) {
> - /* For the unsent_pass we:
> - * discard partially sent pages
> - * For the !unsent_pass (dirty) we:
> - * discard partially dirty pages that were sent
> - * (any partially sent pages were already discarded
> - * by the previous unsent_pass)
> - */
> - postcopy_discard_send_range(ms, fixup_start_addr, host_ratio);
> - }
> -
> /* Clean up the bitmap */
> for (page = fixup_start_addr;
> page < fixup_start_addr + host_ratio; page++) {
> --
> 2.17.1
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 2/3] migration/postcopy: unsentmap is not necessary for postcopy
2019-08-19 6:18 ` [Qemu-devel] [PATCH 2/3] migration/postcopy: unsentmap is not necessary for postcopy Wei Yang
@ 2019-09-24 10:18 ` Dr. David Alan Gilbert
0 siblings, 0 replies; 12+ messages in thread
From: Dr. David Alan Gilbert @ 2019-09-24 10:18 UTC (permalink / raw)
To: Wei Yang; +Cc: pbonzini, qemu-devel, quintela
* 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
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 3/3] migration: remove sent parameter in get_queued_page_not_dirty
2019-08-19 6:18 ` [Qemu-devel] [PATCH 3/3] migration: remove sent parameter in get_queued_page_not_dirty Wei Yang
@ 2019-09-24 10:19 ` Dr. David Alan Gilbert
0 siblings, 0 replies; 12+ messages in thread
From: Dr. David Alan Gilbert @ 2019-09-24 10:19 UTC (permalink / raw)
To: Wei Yang; +Cc: pbonzini, qemu-devel, quintela
* Wei Yang (richardw.yang@linux.intel.com) wrote:
> This is a cleanup for previous removal of unsentmap.
>
> The sent parameter is not necessary now.
>
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
OK, you did...
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> migration/ram.c | 2 +-
> migration/trace-events | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index 066eb4755f..a6d3d09ebd 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->bmap));
> + page);
> } else {
> trace_get_queued_page(block->idstr, (uint64_t)offset, page);
> }
> diff --git a/migration/trace-events b/migration/trace-events
> index 00ffcd5930..858d415d56 100644
> --- a/migration/trace-events
> +++ b/migration/trace-events
> @@ -76,7 +76,7 @@ qemu_file_fclose(void) ""
>
> # ram.c
> get_queued_page(const char *block_name, uint64_t tmp_offset, unsigned long page_abs) "%s/0x%" PRIx64 " page_abs=0x%lx"
> -get_queued_page_not_dirty(const char *block_name, uint64_t tmp_offset, unsigned long page_abs, int sent) "%s/0x%" PRIx64 " page_abs=0x%lx (sent=%d)"
> +get_queued_page_not_dirty(const char *block_name, uint64_t tmp_offset, unsigned long page_abs) "%s/0x%" PRIx64 " page_abs=0x%lx"
> migration_bitmap_sync_start(void) ""
> migration_bitmap_sync_end(uint64_t dirty_pages) "dirty_pages %" PRIu64
> migration_bitmap_clear_dirty(char *str, uint64_t start, uint64_t size, unsigned long page) "rb %s start 0x%"PRIx64" size 0x%"PRIx64" page 0x%lx"
> --
> 2.17.1
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 1/3] migration/postcopy: not necessary to do discard when canonicalizing bitmap
2019-09-24 10:02 ` Dr. David Alan Gilbert
@ 2019-09-25 0:25 ` Wei Yang
0 siblings, 0 replies; 12+ messages in thread
From: Wei Yang @ 2019-09-25 0:25 UTC (permalink / raw)
To: Dr. David Alan Gilbert; +Cc: pbonzini, quintela, Wei Yang, qemu-devel
On Tue, Sep 24, 2019 at 11:02:08AM +0100, Dr. David Alan Gilbert wrote:
>* Wei Yang (richardw.yang@linux.intel.com) wrote:
>> All pages, either partially sent or partially dirty, will be discarded in
>> postcopy_send_discard_bm_ram(), since we update the unsentmap to be
>> unsentmap = unsentmap | dirty in ram_postcopy_send_discard_bitmap().
>>
>> This is not necessary to do discard when canonicalizing bitmap. And by
>> doing so, we separate the page discard into two individual steps:
>>
>> * canonicalize bitmap
>> * discard page
>>
>> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
>
>Yes, I think when I originally wrote it, the set of pages that was
>discarded was different; I think it was actually the set of
>!unsent & dirty - i.e. only pages that had been sent and then redirtied;
>it later got reworked to include unsent pages as well - so this lot can
>be simplified.
>
>
Thanks for your time :-)
>
>Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>
>> ---
>> migration/ram.c | 14 +-------------
>> 1 file changed, 1 insertion(+), 13 deletions(-)
>>
>> diff --git a/migration/ram.c b/migration/ram.c
>> index 35552c090b..075ddc468c 100644
>> --- a/migration/ram.c
>> +++ b/migration/ram.c
>> @@ -2928,7 +2928,7 @@ static int postcopy_each_ram_send_discard(MigrationState *ms)
>> }
>>
>> /**
>> - * postcopy_chunk_hostpages_pass: canocalize bitmap in hostpages
>> + * postcopy_chunk_hostpages_pass: canonicalize bitmap in hostpages
>> *
>> * Helper for postcopy_chunk_hostpages; it's called twice to
>> * canonicalize the two bitmaps, that are similar, but one is
>> @@ -2991,18 +2991,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
>> host_ratio);
>> run_start = QEMU_ALIGN_UP(run_start, host_ratio);
>>
>> - /* Tell the destination to discard this page */
>> - if (unsent_pass || !test_bit(fixup_start_addr, unsentmap)) {
>> - /* For the unsent_pass we:
>> - * discard partially sent pages
>> - * For the !unsent_pass (dirty) we:
>> - * discard partially dirty pages that were sent
>> - * (any partially sent pages were already discarded
>> - * by the previous unsent_pass)
>> - */
>> - postcopy_discard_send_range(ms, fixup_start_addr, host_ratio);
>> - }
>> -
>> /* Clean up the bitmap */
>> for (page = fixup_start_addr;
>> page < fixup_start_addr + host_ratio; page++) {
>> --
>> 2.17.1
>>
>--
>Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
--
Wei Yang
Help you, Help me
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary
2019-08-19 6:18 [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
` (3 preceding siblings ...)
2019-09-16 6:06 ` [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
@ 2019-09-25 9:52 ` Dr. David Alan Gilbert
4 siblings, 0 replies; 12+ messages in thread
From: Dr. David Alan Gilbert @ 2019-09-25 9:52 UTC (permalink / raw)
To: Wei Yang; +Cc: pbonzini, qemu-devel, quintela
* Wei Yang (richardw.yang@linux.intel.com) wrote:
> Three patches to cleanup postcopy:
>
> [1]: split canonicalize bitmap and discard page
> [2]: remove unsentmap since it is not necessary
> [3]: cleanup the get_queued_page_not_dirty
Queued
>
> Wei Yang (3):
> migration/postcopy: not necessary to do discard when canonicalizing
> bitmap
> migration/postcopy: unsentmap is not necessary for postcopy
> migration: remove sent parameter in get_queued_page_not_dirty
>
> include/exec/ram_addr.h | 6 ---
> migration/ram.c | 94 +++++++----------------------------------
> migration/trace-events | 2 +-
> 3 files changed, 16 insertions(+), 86 deletions(-)
>
> --
> 2.17.1
>
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2019-09-25 9:53 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-19 6:18 [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
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2019-09-24 10:02 ` Dr. David Alan Gilbert
2019-09-25 0:25 ` Wei Yang
2019-08-19 6:18 ` [Qemu-devel] [PATCH 2/3] migration/postcopy: unsentmap is not necessary for postcopy Wei Yang
2019-09-24 10:18 ` Dr. David Alan Gilbert
2019-08-19 6:18 ` [Qemu-devel] [PATCH 3/3] migration: remove sent parameter in get_queued_page_not_dirty Wei Yang
2019-09-24 10:19 ` Dr. David Alan Gilbert
2019-09-16 6:06 ` [Qemu-devel] [PATCH 0/3] migration/postcopy: unsentmap is not necessary Wei Yang
2019-09-20 18:53 ` Dr. David Alan Gilbert
2019-09-23 5:56 ` Wei Yang
2019-09-25 9:52 ` [Qemu-devel] " Dr. David Alan Gilbert
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