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Re: [Qemu-devel] [PATCH v2 06/16] Fold postcopy_ram_discard_range into r
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v2 06/16] Fold postcopy_ram_discard_range into ram_discard_range |
Date: |
Fri, 24 Feb 2017 16:02:29 +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>
> >
> > Using the previously created ram_block_discard_range,
> > kill off postcopy_ram_discard_range.
> > ram_discard_range is just a wrapper that does the name lookup.
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> > include/migration/postcopy-ram.h | 7 -------
> > migration/postcopy-ram.c | 30 +-----------------------------
> > migration/ram.c | 24 +++---------------------
> > migration/trace-events | 2 +-
> > 4 files changed, 5 insertions(+), 58 deletions(-)
> >
> > diff --git a/include/migration/postcopy-ram.h
> > b/include/migration/postcopy-ram.h
> > index b6a7491f..43bbbca 100644
> > --- a/include/migration/postcopy-ram.h
> > +++ b/include/migration/postcopy-ram.h
> > @@ -35,13 +35,6 @@ int postcopy_ram_incoming_init(MigrationIncomingState
> > *mis, size_t ram_pages);
> > int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis);
> >
> > /*
> > - * Discard the contents of 'length' bytes from 'start'
> > - * We can assume that if we've been called postcopy_ram_hosttest returned
> > true
> > - */
> > -int postcopy_ram_discard_range(MigrationIncomingState *mis, uint8_t *start,
> > - size_t length);
> > -
> > -/*
> > * Userfault requires us to mark RAM as NOHUGEPAGE prior to discard
> > * however leaving it until after precopy means that most of the precopy
> > * data is still THPd
> > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> > index a40dddb..1e3d22f 100644
> > --- a/migration/postcopy-ram.c
> > +++ b/migration/postcopy-ram.c
> > @@ -200,27 +200,6 @@ out:
> > return ret;
> > }
> >
> > -/**
> > - * postcopy_ram_discard_range: Discard a range of memory.
> > - * We can assume that if we've been called postcopy_ram_hosttest returned
> > true.
> > - *
> > - * @mis: Current incoming migration state.
> > - * @start, @length: range of memory to discard.
> > - *
> > - * returns: 0 on success.
> > - */
> > -int postcopy_ram_discard_range(MigrationIncomingState *mis, uint8_t *start,
> > - size_t length)
> > -{
> > - trace_postcopy_ram_discard_range(start, length);
> > - if (madvise(start, length, MADV_DONTNEED)) {
> > - error_report("%s MADV_DONTNEED: %s", __func__, strerror(errno));
> > - return -1;
> > - }
> > -
> > - return 0;
> > -}
> > -
> > /*
> > * Setup an area of RAM so that it *can* be used for postcopy later; this
> > * must be done right at the start prior to pre-copy.
> > @@ -239,7 +218,7 @@ static int init_range(const char *block_name, void
> > *host_addr,
> > * - we're going to get the copy from the source anyway.
> > * (Precopy will just overwrite this data, so doesn't need the discard)
> > */
> > - if (postcopy_ram_discard_range(mis, host_addr, length)) {
> > + if (ram_discard_range(mis, block_name, 0, length)) {
> > return -1;
> > }
> >
> > @@ -658,13 +637,6 @@ int
> > postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
> > return -1;
> > }
> >
> > -int postcopy_ram_discard_range(MigrationIncomingState *mis, uint8_t *start,
> > - size_t length)
> > -{
> > - assert(0);
> > - return -1;
> > -}
> > -
> > int postcopy_ram_prepare_discard(MigrationIncomingState *mis)
> > {
> > assert(0);
> > diff --git a/migration/ram.c b/migration/ram.c
> > index d33bd21..136996a 100644
> > --- a/migration/ram.c
> > +++ b/migration/ram.c
> > @@ -1845,6 +1845,8 @@ int ram_discard_range(MigrationIncomingState *mis,
> > {
> > int ret = -1;
> >
> > + trace_ram_discard_range(block_name, start, length);
> > +
> > rcu_read_lock();
>
> I think you take the rcu_read_lock() twice: here and in
> ram_block_discard_range().
Hmm, yes I can lose the one in ram_block_discard_range.
> I think you should merge this patch with PATCH 04/16, as it's just code
> copy.
OK, I'd done it as 'add the new one' and 'take the old one away';
but I can do that.
Dave
>
> Laurent
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH v2 01/16] postcopy: Transmit ram size summary word, (continued)
- [Qemu-devel] [PATCH v2 01/16] postcopy: Transmit ram size summary word, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 05/16] postcopy: enhance ram_block_discard_range for hugepages, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 06/16] Fold postcopy_ram_discard_range into ram_discard_range, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 04/16] exec: ram_block_discard_range, Dr. David Alan Gilbert (git), 2017/02/06
- [Qemu-devel] [PATCH v2 09/16] postcopy: Use temporary for placing zero huge pages, Dr. David Alan Gilbert (git), 2017/02/06