* Juan Quintela (quint...@redhat.com) wrote: > "Dr. David Alan Gilbert (git)" <dgilb...@redhat.com> wrote: > > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > > > > Unfortunately madvise DONTNEED doesn't work on hugepagetlb > > so use fallocate(FALLOC_FL_PUNCH_HOLE) > > qemu_fd_getpagesize only sets the page based off a file > > if the file is from hugetlbfs. > > > > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > > --- > > migration/ram.c | 24 ++++++++++++++++++++---- > > 1 file changed, 20 insertions(+), 4 deletions(-) > > > > diff --git a/migration/ram.c b/migration/ram.c > > index fe32836..7afabcd 100644 > > --- a/migration/ram.c > > +++ b/migration/ram.c > > @@ -45,6 +45,10 @@ > > #include "qemu/rcu_queue.h" > > #include "migration/colo.h" > > > > +#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) > > +#include <linux/falloc.h> > > +#endif > > + > > #ifdef DEBUG_MIGRATION_RAM > > #define DPRINTF(fmt, ...) \ > > do { fprintf(stdout, "migration_ram: " fmt, ## __VA_ARGS__); } while > > (0) > > @@ -1866,7 +1870,7 @@ int ram_discard_range(MigrationIncomingState *mis, > > > > uint8_t *host_startaddr = rb->host + start; > > > > - if ((uintptr_t)host_startaddr & (qemu_host_page_size - 1)) { > > + if ((uintptr_t)host_startaddr & (rb->page_size - 1)) { > > error_report("ram_discard_range: Unaligned start address: %p", > > host_startaddr); > > goto err; > > @@ -1874,15 +1878,27 @@ int ram_discard_range(MigrationIncomingState *mis, > > > > if ((start + length) <= rb->used_length) { > > uint8_t *host_endaddr = host_startaddr + length; > > - if ((uintptr_t)host_endaddr & (qemu_host_page_size - 1)) { > > + if ((uintptr_t)host_endaddr & (rb->page_size - 1)) { > > error_report("ram_discard_range: Unaligned end address: %p", > > host_endaddr); > > goto err; > > } > > - errno = ENOTSUP; > > + errno = ENOTSUP; /* If we are missing MADVISE etc */ > > + > > + if (rb->page_size == qemu_host_page_size) { > > #if defined(CONFIG_MADVISE) > > - ret = qemu_madvise(host_startaddr, length, QEMU_MADV_DONTNEED); > > + ret = qemu_madvise(host_startaddr, length, QEMU_MADV_DONTNEED); > > #endif > > + } else { > > + /* Huge page case - unfortunately it can't do DONTNEED, but > > + * it can do the equivalent by FALLOC_FL_PUNCH_HOLE in the > > + * huge page file. > > + */ > > +#ifdef CONFIG_FALLOCATE_PUNCH_HOLE > > + ret = fallocate(rb->fd, FALLOC_FL_PUNCH_HOLE | > > FALLOC_FL_KEEP_SIZE, > > + start, length); > > +#endif > > + } > > if (ret) { > > error_report("ram_discard_range: Failed to discard range " > > "%s:%" PRIx64 " +%zx (%d)", > > Can we move this to qemu-posix or similar? > qemu_punch_hole() or similar and just put all the magic there?
I'm trying but it's tricky. The problem is that: a) To be able to tell which you need you need the pagesize of the area b) Then you need the fd if it is a hugepage (You can get (a) from (b) by a syscall we already do once) c) If it's normal RAM you need the memory address but... d) If it's a hugepage you need the offset in the file which is a mess; so you either have to pass all those parameters, or end up passing a RAMBlock* which doesn't feel like it should make its way into any of the os-* files. I could move it to exec.c that already has some ifdef on OSs; what do you think? Dave > For the rest, I am ok with it. -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK