| Message ID | 20190913102538.24167-1-dgilbert@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Automatic RCU read unlock | expand |
* Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > This patch uses glib's g_auto mechanism to automatically free > rcu_read_lock's at the end of the block. Given that humans > have a habit of forgetting an error path somewhere it's > best to leave it to the compiler. Queued > v3 > Add block-head version of macro > Rename > Add docs > Convert more cases using the block-head version > > Dr. David Alan Gilbert (5): > rcu: Add automatically released rcu_read_lock variants > migration: Fix missing rcu_read_unlock > migration: Use automatic rcu_read unlock in ram.c > migration: Use automatic rcu_read unlock in rdma.c > rcu: Use automatic rc_read unlock in core memory/exec code > > docs/devel/rcu.txt | 16 +++ > exec.c | 120 +++++++--------- > include/exec/ram_addr.h | 138 +++++++++---------- > include/qemu/rcu.h | 25 ++++ > memory.c | 15 +- > migration/ram.c | 295 +++++++++++++++++++--------------------- > migration/rdma.c | 57 ++------ > 7 files changed, 310 insertions(+), 356 deletions(-) > > -- > 2.21.0 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
* Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > This patch uses glib's g_auto mechanism to automatically free > rcu_read_lock's at the end of the block. Given that humans > have a habit of forgetting an error path somewhere it's > best to leave it to the compiler. I've had to unqueue this - clang doesn't like the apparently unused auto variable; we need to find a way to make that happy. Dave > v3 > Add block-head version of macro > Rename > Add docs > Convert more cases using the block-head version > > Dr. David Alan Gilbert (5): > rcu: Add automatically released rcu_read_lock variants > migration: Fix missing rcu_read_unlock > migration: Use automatic rcu_read unlock in ram.c > migration: Use automatic rcu_read unlock in rdma.c > rcu: Use automatic rc_read unlock in core memory/exec code > > docs/devel/rcu.txt | 16 +++ > exec.c | 120 +++++++--------- > include/exec/ram_addr.h | 138 +++++++++---------- > include/qemu/rcu.h | 25 ++++ > memory.c | 15 +- > migration/ram.c | 295 +++++++++++++++++++--------------------- > migration/rdma.c | 57 ++------ > 7 files changed, 310 insertions(+), 356 deletions(-) > > -- > 2.21.0 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On 25/09/19 15:13, Dr. David Alan Gilbert wrote: > * Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: >> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> >> >> This patch uses glib's g_auto mechanism to automatically free >> rcu_read_lock's at the end of the block. Given that humans >> have a habit of forgetting an error path somewhere it's >> best to leave it to the compiler. > > I've had to unqueue this - clang doesn't like the apparently unused > auto variable; we need to find a way to make that happy. __attribute__((unused))? Paolo > Dave > >> v3 >> Add block-head version of macro >> Rename >> Add docs >> Convert more cases using the block-head version >> >> Dr. David Alan Gilbert (5): >> rcu: Add automatically released rcu_read_lock variants >> migration: Fix missing rcu_read_unlock >> migration: Use automatic rcu_read unlock in ram.c >> migration: Use automatic rcu_read unlock in rdma.c >> rcu: Use automatic rc_read unlock in core memory/exec code >> >> docs/devel/rcu.txt | 16 +++ >> exec.c | 120 +++++++--------- >> include/exec/ram_addr.h | 138 +++++++++---------- >> include/qemu/rcu.h | 25 ++++ >> memory.c | 15 +- >> migration/ram.c | 295 +++++++++++++++++++--------------------- >> migration/rdma.c | 57 ++------ >> 7 files changed, 310 insertions(+), 356 deletions(-) >> >> -- >> 2.21.0 >> >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >
* Paolo Bonzini (pbonzini@redhat.com) wrote: > On 25/09/19 15:13, Dr. David Alan Gilbert wrote: > > * Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: > >> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > >> > >> This patch uses glib's g_auto mechanism to automatically free > >> rcu_read_lock's at the end of the block. Given that humans > >> have a habit of forgetting an error path somewhere it's > >> best to leave it to the compiler. > > > > I've had to unqueue this - clang doesn't like the apparently unused > > auto variable; we need to find a way to make that happy. > > __attribute__((unused))? I worry that if I do that, then it'll optimise it out. Dave > Paolo > > > Dave > > > >> v3 > >> Add block-head version of macro > >> Rename > >> Add docs > >> Convert more cases using the block-head version > >> > >> Dr. David Alan Gilbert (5): > >> rcu: Add automatically released rcu_read_lock variants > >> migration: Fix missing rcu_read_unlock > >> migration: Use automatic rcu_read unlock in ram.c > >> migration: Use automatic rcu_read unlock in rdma.c > >> rcu: Use automatic rc_read unlock in core memory/exec code > >> > >> docs/devel/rcu.txt | 16 +++ > >> exec.c | 120 +++++++--------- > >> include/exec/ram_addr.h | 138 +++++++++---------- > >> include/qemu/rcu.h | 25 ++++ > >> memory.c | 15 +- > >> migration/ram.c | 295 +++++++++++++++++++--------------------- > >> migration/rdma.c | 57 ++------ > >> 7 files changed, 310 insertions(+), 356 deletions(-) > >> > >> -- > >> 2.21.0 > >> > >> > > -- > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Wed, Sep 25, 2019 at 04:28:58PM +0100, Dr. David Alan Gilbert wrote: > * Paolo Bonzini (pbonzini@redhat.com) wrote: > > On 25/09/19 15:13, Dr. David Alan Gilbert wrote: > > > * Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: > > >> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > >> > > >> This patch uses glib's g_auto mechanism to automatically free > > >> rcu_read_lock's at the end of the block. Given that humans > > >> have a habit of forgetting an error path somewhere it's > > >> best to leave it to the compiler. > > > > > > I've had to unqueue this - clang doesn't like the apparently unused > > > auto variable; we need to find a way to make that happy. > > > > __attribute__((unused))? > > I worry that if I do that, then it'll optimise it out. Can you just insert a dummy use of the variable. eg libvirt does this by just taking the address of the unused variable and casting the result to void. Regards, Daniel
On 25/09/19 17:28, Dr. David Alan Gilbert wrote: > * Paolo Bonzini (pbonzini@redhat.com) wrote: >> On 25/09/19 15:13, Dr. David Alan Gilbert wrote: >>> * Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: >>>> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> >>>> >>>> This patch uses glib's g_auto mechanism to automatically free >>>> rcu_read_lock's at the end of the block. Given that humans >>>> have a habit of forgetting an error path somewhere it's >>>> best to leave it to the compiler. >>> >>> I've had to unqueue this - clang doesn't like the apparently unused >>> auto variable; we need to find a way to make that happy. >> >> __attribute__((unused))? > > I worry that if I do that, then it'll optimise it out. It cannot, since the function passed to the cleanup attribute can have side effects. Paolo > > Dave > >> Paolo >> >>> Dave >>> >>>> v3 >>>> Add block-head version of macro >>>> Rename >>>> Add docs >>>> Convert more cases using the block-head version >>>> >>>> Dr. David Alan Gilbert (5): >>>> rcu: Add automatically released rcu_read_lock variants >>>> migration: Fix missing rcu_read_unlock >>>> migration: Use automatic rcu_read unlock in ram.c >>>> migration: Use automatic rcu_read unlock in rdma.c >>>> rcu: Use automatic rc_read unlock in core memory/exec code >>>> >>>> docs/devel/rcu.txt | 16 +++ >>>> exec.c | 120 +++++++--------- >>>> include/exec/ram_addr.h | 138 +++++++++---------- >>>> include/qemu/rcu.h | 25 ++++ >>>> memory.c | 15 +- >>>> migration/ram.c | 295 +++++++++++++++++++--------------------- >>>> migration/rdma.c | 57 ++------ >>>> 7 files changed, 310 insertions(+), 356 deletions(-) >>>> >>>> -- >>>> 2.21.0 >>>> >>>> >>> -- >>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >>> >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com> This patch uses glib's g_auto mechanism to automatically free rcu_read_lock's at the end of the block. Given that humans have a habit of forgetting an error path somewhere it's best to leave it to the compiler. v3 Add block-head version of macro Rename Add docs Convert more cases using the block-head version Dr. David Alan Gilbert (5): rcu: Add automatically released rcu_read_lock variants migration: Fix missing rcu_read_unlock migration: Use automatic rcu_read unlock in ram.c migration: Use automatic rcu_read unlock in rdma.c rcu: Use automatic rc_read unlock in core memory/exec code docs/devel/rcu.txt | 16 +++ exec.c | 120 +++++++--------- include/exec/ram_addr.h | 138 +++++++++---------- include/qemu/rcu.h | 25 ++++ memory.c | 15 +- migration/ram.c | 295 +++++++++++++++++++--------------------- migration/rdma.c | 57 ++------ 7 files changed, 310 insertions(+), 356 deletions(-)