From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Juan Quintela <quintela@redhat.com>
Cc: aarcange@redhat.com, yamahata@private.email.ne.jp,
liang.z.li@intel.com, qemu-devel@nongnu.org, luis@cs.umu.se,
amit.shah@redhat.com, pbonzini@redhat.com,
david@gibson.dropbear.id.au
Subject: Re: [Qemu-devel] [PATCH v7 33/42] postcopy_ram.c: place_page and helpers
Date: Wed, 23 Sep 2015 17:45:00 +0100 [thread overview]
Message-ID: <20150923164500.GB13453@work-vm> (raw)
In-Reply-To: <87615ngiky.fsf@neno.neno>
* Juan Quintela (quintela@redhat.com) wrote:
> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote:
> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> >
> > postcopy_place_page (etc) provide a way for postcopy to place a page
> > into guests memory atomically (using the copy ioctl on the ufd).
> >
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>
> > --- a/include/migration/postcopy-ram.h
> > +++ b/include/migration/postcopy-ram.h
> > @@ -69,4 +69,20 @@ void postcopy_discard_send_range(MigrationState *ms, PostcopyDiscardState *pds,
> > void postcopy_discard_send_finish(MigrationState *ms,
> > PostcopyDiscardState *pds);
> >
> > +/*
> > + * Place a page (from) at (host) efficiently
> > + * There are restrictions on how 'from' must be mapped, in general best
> > + * to use other postcopy_ routines to allocate.
> > + * returns 0 on success
> > + */
> > +int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from,
> > + bool all_zero);
> > +
> > +/*
> > + * Allocate a page of memory that can be mapped at a later point in time
> > + * using postcopy_place_page
> > + * Returns: Pointer to allocated page
> > + */
> > +void *postcopy_get_tmp_page(MigrationIncomingState *mis);
> > +
>
> I don't think that this makes sense, but wouldn't have been a good idea
> to ask for the address that we want as a hint. That could help with
> fragmentation, no?
I think that we may be able to do something if we were to transmit huge
pages (which is a separate problem); but at the moment all get_tmp_page
does it an mmap with the right set of flags, and that mmap only happens
once for all the pages; it's only the backing page that gets moved,
that mmap is reused for the whole run.
> > +/*
> > + * Place a host page (from) at (host) atomically
> > + * all_zero: Hint that the page being placed is 0 throughout
> > + * returns 0 on success
> > + */
> > +int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from,
> > + bool all_zero)
>
> postcop_place_page() and postcop_place_zero_page()? They just share a
> trace point :p
Done.
> > +{
> > + if (!all_zero) {
> > + struct uffdio_copy copy_struct;
> > +
> > + copy_struct.dst = (uint64_t)(uintptr_t)host;
> > + copy_struct.src = (uint64_t)(uintptr_t)from;
> > + copy_struct.len = getpagesize();
> > + copy_struct.mode = 0;
> > +
> > + /* copy also acks to the kernel waking the stalled thread up
> > + * TODO: We can inhibit that ack and only do it if it was requested
> > + * which would be slightly cheaper, but we'd have to be careful
> > + * of the order of updating our page state.
> > + */
> > + if (ioctl(mis->userfault_fd, UFFDIO_COPY, ©_struct)) {
> > + int e = errno;
> > + error_report("%s: %s copy host: %p from: %p",
> > + __func__, strerror(e), host, from);
> > +
> > + return -e;
> > + }
> > + } else {
> > + struct uffdio_zeropage zero_struct;
> > +
> > + zero_struct.range.start = (uint64_t)(uintptr_t)host;
> > + zero_struct.range.len = getpagesize();
> > + zero_struct.mode = 0;
> > +
> > + if (ioctl(mis->userfault_fd, UFFDIO_ZEROPAGE, &zero_struct)) {
> > + int e = errno;
> > + error_report("%s: %s zero host: %p from: %p",
> > + __func__, strerror(e), host, from);
> > +
> > + return -e;
> > + }
> > + }
> > +
> > + trace_postcopy_place_page(host, all_zero);
> > + return 0;
> > +}
>
> I really think that the userfault code should be in a linux specific
> file, but that can be done late, so I will not insist O:-)
I think it will make sense once we have another OSs view of what the interface
should look like, and then we can get an abstraction that works for both and
move the implementations out.
Dave
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
next prev parent reply other threads:[~2015-09-23 16:45 UTC|newest]
Thread overview: 209+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-16 10:26 [Qemu-devel] [PATCH v7 00/42] Postcopy implementation Dr. David Alan Gilbert (git)
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 01/42] Start documenting how postcopy works Dr. David Alan Gilbert (git)
2015-06-17 11:42 ` Juan Quintela
2015-06-17 12:30 ` Dr. David Alan Gilbert
2015-06-18 7:50 ` Li, Liang Z
2015-06-18 8:10 ` Dr. David Alan Gilbert
2015-06-18 8:28 ` Paolo Bonzini
2015-06-19 17:52 ` Dr. David Alan Gilbert
2015-06-26 6:46 ` Yang Hongyang
2015-06-26 7:53 ` zhanghailiang
2015-06-26 8:00 ` Yang Hongyang
2015-06-26 8:10 ` Dr. David Alan Gilbert
2015-06-26 8:19 ` Yang Hongyang
2015-08-04 5:20 ` Amit Shah
2015-08-05 12:21 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 02/42] Provide runtime Target page information Dr. David Alan Gilbert (git)
2015-06-17 11:43 ` Juan Quintela
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 03/42] Init page sizes in qtest Dr. David Alan Gilbert (git)
2015-06-17 11:49 ` Juan Quintela
2015-07-06 6:14 ` Amit Shah
2015-08-04 5:23 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 04/42] qemu_ram_block_from_host Dr. David Alan Gilbert (git)
2015-06-17 11:54 ` Juan Quintela
2015-07-10 8:36 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 05/42] Add qemu_get_buffer_less_copy to avoid copies some of the time Dr. David Alan Gilbert (git)
2015-06-17 11:57 ` Juan Quintela
2015-06-17 12:33 ` Dr. David Alan Gilbert
2015-07-13 9:08 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 06/42] Add wrapper for setting blocking status on a QEMUFile Dr. David Alan Gilbert (git)
2015-06-17 11:59 ` Juan Quintela
2015-06-17 12:34 ` Dr. David Alan Gilbert
2015-06-17 12:57 ` Juan Quintela
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 07/42] ram_debug_dump_bitmap: Dump a migration bitmap as text Dr. David Alan Gilbert (git)
2015-06-17 12:17 ` Juan Quintela
2015-06-19 17:04 ` Dr. David Alan Gilbert
2015-07-13 10:15 ` Juan Quintela
2015-07-13 9:12 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 08/42] migrate_init: Call from savevm Dr. David Alan Gilbert (git)
2015-06-17 12:18 ` Juan Quintela
2015-07-13 9:13 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 09/42] Rename save_live_complete to save_live_complete_precopy Dr. David Alan Gilbert (git)
2015-06-17 12:20 ` Juan Quintela
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 10/42] Return path: Open a return path on QEMUFile for sockets Dr. David Alan Gilbert (git)
2015-06-17 12:23 ` Juan Quintela
2015-06-17 17:07 ` Dr. David Alan Gilbert
2015-07-13 10:12 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 11/42] Return path: socket_writev_buffer: Block even on non-blocking fd's Dr. David Alan Gilbert (git)
2015-06-17 12:28 ` Juan Quintela
2015-06-19 17:18 ` Dr. David Alan Gilbert
2015-07-13 12:37 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 12/42] Migration commands Dr. David Alan Gilbert (git)
2015-06-17 12:31 ` Juan Quintela
2015-06-19 17:38 ` Dr. David Alan Gilbert
2015-07-13 12:45 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 13/42] Return path: Control commands Dr. David Alan Gilbert (git)
2015-06-17 12:49 ` Juan Quintela
2015-06-23 18:57 ` Dr. David Alan Gilbert
2015-07-13 12:55 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 14/42] Return path: Send responses from destination to source Dr. David Alan Gilbert (git)
2015-06-17 16:30 ` Juan Quintela
2015-06-19 18:42 ` Dr. David Alan Gilbert
2015-07-01 9:29 ` Juan Quintela
2015-08-06 12:18 ` Dr. David Alan Gilbert
2015-07-15 7:31 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 15/42] Return path: Source handling of return path Dr. David Alan Gilbert (git)
2015-07-13 10:29 ` Juan Quintela
2015-08-18 10:23 ` Dr. David Alan Gilbert
2015-07-15 7:50 ` Amit Shah
2015-07-16 11:32 ` Dr. David Alan Gilbert
2015-08-05 8:06 ` zhanghailiang
2015-08-18 10:45 ` Dr. David Alan Gilbert
2015-08-18 11:29 ` zhanghailiang
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 16/42] Rework loadvm path for subloops Dr. David Alan Gilbert (git)
2015-07-13 10:33 ` Juan Quintela
2015-07-15 9:34 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 17/42] Add migration-capability boolean for postcopy-ram Dr. David Alan Gilbert (git)
2015-06-16 15:43 ` Eric Blake
2015-06-16 15:58 ` Dr. David Alan Gilbert
2015-07-15 9:39 ` Amit Shah
2015-07-13 10:35 ` Juan Quintela
2015-07-15 9:40 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 18/42] Add wrappers and handlers for sending/receiving the postcopy-ram migration messages Dr. David Alan Gilbert (git)
2015-07-13 11:02 ` Juan Quintela
2015-07-20 10:13 ` Amit Shah
2015-08-26 14:48 ` Dr. David Alan Gilbert
2015-07-20 10:06 ` Amit Shah
2015-07-27 9:55 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 19/42] MIG_CMD_PACKAGED: Send a packaged chunk of migration stream Dr. David Alan Gilbert (git)
2015-07-13 11:07 ` Juan Quintela
2015-07-21 6:11 ` Amit Shah
2015-07-27 17:28 ` Dr. David Alan Gilbert
2015-08-04 5:27 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 20/42] Modify save_live_pending for postcopy Dr. David Alan Gilbert (git)
2015-07-13 11:12 ` Juan Quintela
2015-07-31 16:13 ` Dr. David Alan Gilbert
2015-07-21 6:17 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 21/42] postcopy: OS support test Dr. David Alan Gilbert (git)
2015-07-13 11:20 ` Juan Quintela
2015-07-13 16:31 ` Dr. David Alan Gilbert
2015-07-21 7:29 ` Amit Shah
2015-07-27 17:38 ` Dr. David Alan Gilbert
2015-08-04 5:28 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 22/42] migrate_start_postcopy: Command to trigger transition to postcopy Dr. David Alan Gilbert (git)
2015-07-13 11:23 ` Juan Quintela
2015-07-13 17:13 ` Dr. David Alan Gilbert
2015-07-13 18:07 ` Juan Quintela
2015-07-21 7:40 ` Amit Shah
2015-09-24 9:59 ` Dr. David Alan Gilbert
2015-09-24 14:20 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 23/42] MIGRATION_STATUS_POSTCOPY_ACTIVE: Add new migration state Dr. David Alan Gilbert (git)
2015-07-13 11:27 ` Juan Quintela
2015-07-13 15:53 ` Dr. David Alan Gilbert
2015-07-13 16:26 ` Juan Quintela
2015-07-13 16:48 ` Dr. David Alan Gilbert
2015-07-13 18:05 ` Juan Quintela
2015-07-21 10:33 ` Amit Shah
2015-09-23 17:04 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 24/42] Add qemu_savevm_state_complete_postcopy Dr. David Alan Gilbert (git)
2015-07-13 11:35 ` Juan Quintela
2015-07-13 15:33 ` Dr. David Alan Gilbert
2015-07-21 10:42 ` Amit Shah
2015-07-27 17:58 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 25/42] Postcopy: Maintain sentmap and calculate discard Dr. David Alan Gilbert (git)
2015-07-13 11:47 ` Juan Quintela
2015-09-15 17:01 ` Dr. David Alan Gilbert
2015-07-21 11:36 ` Amit Shah
2015-07-31 16:51 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 26/42] postcopy: Incoming initialisation Dr. David Alan Gilbert (git)
2015-07-13 12:04 ` Juan Quintela
2015-09-23 19:06 ` Dr. David Alan Gilbert
2015-07-22 6:19 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 27/42] postcopy: ram_enable_notify to switch on userfault Dr. David Alan Gilbert (git)
2015-07-13 12:10 ` Juan Quintela
2015-07-13 17:36 ` Dr. David Alan Gilbert
2015-07-23 5:22 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 28/42] Postcopy: Postcopy startup in migration thread Dr. David Alan Gilbert (git)
2015-07-13 12:56 ` Juan Quintela
2015-07-13 17:56 ` Dr. David Alan Gilbert
2015-07-13 18:09 ` Juan Quintela
2015-09-23 17:56 ` Dr. David Alan Gilbert
2015-07-23 5:53 ` Amit Shah
2015-07-23 5:55 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 29/42] Postcopy end in migration_thread Dr. David Alan Gilbert (git)
2015-07-13 13:15 ` Juan Quintela
2015-07-23 6:41 ` Amit Shah
2015-08-04 11:31 ` Dr. David Alan Gilbert
2015-07-23 6:41 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 30/42] Page request: Add MIG_RP_MSG_REQ_PAGES reverse command Dr. David Alan Gilbert (git)
2015-07-13 13:24 ` Juan Quintela
2015-08-06 14:15 ` Dr. David Alan Gilbert
2015-07-23 6:50 ` Amit Shah
2015-08-06 14:21 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 31/42] Page request: Process incoming page request Dr. David Alan Gilbert (git)
2015-07-14 9:18 ` Juan Quintela
2015-08-06 10:45 ` Dr. David Alan Gilbert
2015-10-20 10:29 ` Juan Quintela
2015-07-23 12:23 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 32/42] Page request: Consume pages off the post-copy queue Dr. David Alan Gilbert (git)
2015-07-14 9:40 ` Juan Quintela
2015-09-16 18:36 ` Dr. David Alan Gilbert
2015-07-27 6:05 ` Amit Shah
2015-09-16 18:48 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 33/42] postcopy_ram.c: place_page and helpers Dr. David Alan Gilbert (git)
2015-07-14 10:05 ` Juan Quintela
2015-07-27 6:11 ` Amit Shah
2015-09-23 16:45 ` Dr. David Alan Gilbert [this message]
2015-07-27 6:11 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 34/42] Postcopy: Use helpers to map pages during migration Dr. David Alan Gilbert (git)
2015-07-14 12:34 ` Juan Quintela
2015-07-17 17:31 ` Dr. David Alan Gilbert
2015-07-27 7:39 ` Amit Shah
2015-08-06 11:22 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 35/42] Don't sync dirty bitmaps in postcopy Dr. David Alan Gilbert (git)
2015-07-14 12:36 ` Juan Quintela
2015-07-14 13:13 ` Dr. David Alan Gilbert
2015-07-27 7:43 ` Amit Shah
2015-07-31 9:50 ` Dr. David Alan Gilbert
2015-08-04 5:46 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 36/42] Host page!=target page: Cleanup bitmaps Dr. David Alan Gilbert (git)
2015-07-14 15:01 ` Juan Quintela
2015-07-31 15:53 ` Dr. David Alan Gilbert
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 37/42] Postcopy; Handle userfault requests Dr. David Alan Gilbert (git)
2015-07-14 15:10 ` Juan Quintela
2015-07-14 15:15 ` Dr. David Alan Gilbert
2015-07-14 15:25 ` Juan Quintela
2015-07-27 14:29 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 38/42] Start up a postcopy/listener thread ready for incoming page data Dr. David Alan Gilbert (git)
2015-07-14 15:12 ` Juan Quintela
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 39/42] postcopy: Wire up loadvm_postcopy_handle_ commands Dr. David Alan Gilbert (git)
2015-07-14 15:14 ` Juan Quintela
2015-07-28 5:53 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 40/42] End of migration for postcopy Dr. David Alan Gilbert (git)
2015-07-14 15:15 ` Juan Quintela
2015-07-28 5:55 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 41/42] Disable mlock around incoming postcopy Dr. David Alan Gilbert (git)
2015-07-14 15:22 ` Juan Quintela
2015-07-28 6:02 ` Amit Shah
2015-07-28 11:32 ` Juan Quintela
2015-08-06 14:55 ` Dr. David Alan Gilbert
2015-08-07 3:05 ` zhanghailiang
2015-09-24 10:36 ` Dr. David Alan Gilbert
2015-07-28 6:02 ` Amit Shah
2015-06-16 10:26 ` [Qemu-devel] [PATCH v7 42/42] Inhibit ballooning during postcopy Dr. David Alan Gilbert (git)
2015-07-14 15:24 ` Juan Quintela
2015-07-28 6:15 ` Amit Shah
2015-07-28 9:08 ` Dr. David Alan Gilbert
2015-07-28 10:01 ` Amit Shah
2015-07-28 11:16 ` Dr. David Alan Gilbert
2015-07-28 6:21 ` [Qemu-devel] [PATCH v7 00/42] Postcopy implementation Amit Shah
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