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Re: [Qemu-devel] [PATCH v2 08/16] postcopy: Plumb pagesize down into pla
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v2 08/16] postcopy: Plumb pagesize down into place helpers |
Date: |
Fri, 24 Feb 2017 15:21:26 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
* Laurent Vivier (address@hidden) wrote:
> On 06/02/2017 18:32, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > Now we deal with normal size pages and huge pages we need
> > to tell the place handlers the size we're dealing with
> > and make sure the temporary page is large enough.
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> > include/migration/postcopy-ram.h | 6 +++--
> > migration/postcopy-ram.c | 47
> > ++++++++++++++++++++++++----------------
> > migration/ram.c | 15 +++++++------
> > 3 files changed, 40 insertions(+), 28 deletions(-)
> >
> > diff --git a/include/migration/postcopy-ram.h
> > b/include/migration/postcopy-ram.h
> > index 43bbbca..8e036b9 100644
> > --- a/include/migration/postcopy-ram.h
> > +++ b/include/migration/postcopy-ram.h
> > @@ -74,13 +74,15 @@ void postcopy_discard_send_finish(MigrationState *ms,
> > * to use other postcopy_ routines to allocate.
> > * returns 0 on success
> > */
> > -int postcopy_place_page(MigrationIncomingState *mis, void *host, void
> > *from);
> > +int postcopy_place_page(MigrationIncomingState *mis, void *host, void
> > *from,
> > + size_t pagesize);
> >
> > /*
> > * Place a zero page at (host) atomically
> > * returns 0 on success
> > */
> > -int postcopy_place_page_zero(MigrationIncomingState *mis, void *host);
> > +int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
> > + size_t pagesize);
> >
> > /*
> > * Allocate a page of memory that can be mapped at a later point in time
> > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> > index 1e3d22f..a8b7fed 100644
> > --- a/migration/postcopy-ram.c
> > +++ b/migration/postcopy-ram.c
> > @@ -321,7 +321,7 @@ int
> > postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
> > migrate_send_rp_shut(mis, qemu_file_get_error(mis->from_src_file) !=
> > 0);
> >
> > if (mis->postcopy_tmp_page) {
> > - munmap(mis->postcopy_tmp_page, getpagesize());
> > + munmap(mis->postcopy_tmp_page, mis->largest_page_size);
> > mis->postcopy_tmp_page = NULL;
> > }
> > trace_postcopy_ram_incoming_cleanup_exit();
> > @@ -543,13 +543,14 @@ int postcopy_ram_enable_notify(MigrationIncomingState
> > *mis)
> > * Place a host page (from) at (host) atomically
> > * returns 0 on success
> > */
> > -int postcopy_place_page(MigrationIncomingState *mis, void *host, void
> > *from)
> > +int postcopy_place_page(MigrationIncomingState *mis, void *host, void
> > *from,
> > + size_t pagesize)
> > {
> > 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.len = pagesize;
> > copy_struct.mode = 0;
> >
> > /* copy also acks to the kernel waking the stalled thread up
> > @@ -559,8 +560,8 @@ int postcopy_place_page(MigrationIncomingState *mis,
> > void *host, void *from)
> > */
> > 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);
> > + error_report("%s: %s copy host: %p from: %p (size: %zd)",
> > + __func__, strerror(e), host, from, pagesize);
> >
> > return -e;
> > }
> > @@ -573,23 +574,29 @@ int postcopy_place_page(MigrationIncomingState *mis,
> > void *host, void *from)
> > * Place a zero page at (host) atomically
> > * returns 0 on success
> > */
> > -int postcopy_place_page_zero(MigrationIncomingState *mis, void *host)
> > +int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
> > + size_t pagesize)
> > {
> > - struct uffdio_zeropage zero_struct;
> > + trace_postcopy_place_page_zero(host);
> >
> > - zero_struct.range.start = (uint64_t)(uintptr_t)host;
> > - zero_struct.range.len = getpagesize();
> > - zero_struct.mode = 0;
> > + if (pagesize == getpagesize()) {
> > + 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",
> > - __func__, strerror(e), host);
> > + if (ioctl(mis->userfault_fd, UFFDIO_ZEROPAGE, &zero_struct)) {
> > + int e = errno;
> > + error_report("%s: %s zero host: %p",
> > + __func__, strerror(e), host);
> >
> > - return -e;
> > + return -e;
> > + }
> > + } else {
> > + /* TODO: The kernel can't use UFFDIO_ZEROPAGE for hugepages */
> > + assert(0);
> > }
> >
> > - trace_postcopy_place_page_zero(host);
> > return 0;
> > }
> >
> > @@ -604,7 +611,7 @@ int postcopy_place_page_zero(MigrationIncomingState
> > *mis, void *host)
> > void *postcopy_get_tmp_page(MigrationIncomingState *mis)
> > {
> > if (!mis->postcopy_tmp_page) {
> > - mis->postcopy_tmp_page = mmap(NULL, getpagesize(),
> > + mis->postcopy_tmp_page = mmap(NULL, mis->largest_page_size,
> > PROT_READ | PROT_WRITE, MAP_PRIVATE |
> > MAP_ANONYMOUS, -1, 0);
> > if (mis->postcopy_tmp_page == MAP_FAILED) {
> > @@ -649,13 +656,15 @@ int postcopy_ram_enable_notify(MigrationIncomingState
> > *mis)
> > return -1;
> > }
> >
> > -int postcopy_place_page(MigrationIncomingState *mis, void *host, void
> > *from)
> > +int postcopy_place_page(MigrationIncomingState *mis, void *host, void
> > *from,
> > + size_t pagesize)
> > {
> > assert(0);
> > return -1;
> > }
> >
> > -int postcopy_place_page_zero(MigrationIncomingState *mis, void *host)
> > +int postcopy_place_page_zero(MigrationIncomingState *mis, void *host,
> > + size_t pagesize)
> > {
> > assert(0);
> > return -1;
> > diff --git a/migration/ram.c b/migration/ram.c
> > index 136996a..ff448ef 100644
> > --- a/migration/ram.c
> > +++ b/migration/ram.c
> > @@ -2354,6 +2354,7 @@ static int ram_load_postcopy(QEMUFile *f)
> > void *host = NULL;
> > void *page_buffer = NULL;
> > void *place_source = NULL;
> > + RAMBlock *block = NULL;
> > uint8_t ch;
> >
> > addr = qemu_get_be64(f);
> > @@ -2363,7 +2364,7 @@ static int ram_load_postcopy(QEMUFile *f)
> > trace_ram_load_postcopy_loop((uint64_t)addr, flags);
> > place_needed = false;
> > if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE)) {
> > - RAMBlock *block = ram_block_from_stream(f, flags);
> > + block = ram_block_from_stream(f, flags);
> >
> > host = host_from_ram_block_offset(block, addr);
> > if (!host) {
> > @@ -2438,14 +2439,14 @@ static int ram_load_postcopy(QEMUFile *f)
> >
> > if (place_needed) {
> > /* This gets called at the last target page in the host page */
> > + void *place_dest = host + TARGET_PAGE_SIZE - block->page_size;
> > +
> > if (all_zero) {
> > - ret = postcopy_place_page_zero(mis,
> > - host + TARGET_PAGE_SIZE -
> > - qemu_host_page_size);
> > + ret = postcopy_place_page_zero(mis, place_dest,
> > + block->page_size);
> > } else {
> > - ret = postcopy_place_page(mis, host + TARGET_PAGE_SIZE -
> > - qemu_host_page_size,
> > - place_source);
> > + ret = postcopy_place_page(mis, place_dest,
> > + place_source, block->page_size);
> > }
> > }
> > if (!ret) {
> >
>
> I think the "postcopy_tmp_page" part should be better in PATCH 07/16, so
> we know why you introduce the largest_page_size field, and this avoids
> to mix two kinds of change in this one (to place page and adjust tmp_page).
Well I did mention it in the commit message at the top of 7.
> Anyway:
> Reviewed-by: Laurent Vivier <address@hidden>
Thanks
Dave
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH v2 02/16] postcopy: Transmit and compare individual page sizes, (continued)
- [Qemu-devel] [PATCH v2 07/16] postcopy: Record largest page size, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 11/16] postcopy: Mask fault addresses to huge page boundary, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 08/16] postcopy: Plumb pagesize down into place helpers, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 13/16] postcopy: Allow hugepages, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 14/16] postcopy: Update userfaultfd.h header, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 12/16] postcopy: Send whole huge pages, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 16/16] postcopy: Add doc about hugepages and postcopy, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 10/16] postcopy: Load huge pages in one go, Dr. David Alan Gilbert (git), 2017/02/06