| Message ID | 20170106182823.1960-6-dgilbert@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
"Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: > From: "Dr. David Alan Gilbert" <dgilbert@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 <dgilbert@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? For the rest, I am ok with it.
* Juan Quintela (quintela@redhat.com) wrote: > "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: > > From: "Dr. David Alan Gilbert" <dgilbert@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 <dgilbert@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 / dgilbert@redhat.com / Manchester, UK
"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote: > * Juan Quintela (quintela@redhat.com) wrote: >> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> wrote: >> > From: "Dr. David Alan Gilbert" <dgilbert@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 <dgilbert@redhat.com> >> > +#if defined(CONFIG_FALLOCATE_PUNCH_HOLE) >> > +#include <linux/falloc.h> >> > +#endif I hate this in generic code :-() I think that the function will have to be called: qemu_ram_punch_hole(RAMBblock *, length); Put it all together at the beggining of the file? What I don't want is that if someone arrives with a way to do this in other OS, we need to put yet more ifdefs. I preffer very much that it just have to define a function with that semantics. Agreed that this is a mess, but I can't think of an easier way of doing it either :-() >> > @@ -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 / dgilbert@redhat.com / Manchester, UK
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)",