[Xen-devel] [PATCH 3/6] libxl: events: Deregister, don't just modify, sigchld pipe fd
We want to have no fd events registered when we are idle. This
implies that we must be able to deregister our interest in the sigchld
self-pipe fd, not just modify to request no events.
Signed-off-by: Ian Jackson
Acked-by: Ian Campbell
Tested-by: Ian Campbell
Release-Acked-by: Konrad Rzeszutek Wilk
---
tools/libxl/libxl_fork.c |9 +
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/tools/libxl/libxl_fork.c b/tools/libxl/libxl_fork.c
index fa15095..144208a 100644
--- a/tools/libxl/libxl_fork.c
+++ b/tools/libxl/libxl_fork.c
@@ -372,15 +372,8 @@ static void sigchld_user_remove(libxl_ctx *ctx) /*
idempotent */
void libxl__sigchld_notneeded(libxl__gc *gc) /* non-reentrant, idempotent */
{
-int rc;
-
sigchld_user_remove(CTX);
-
-if (libxl__ev_fd_isregistered(&CTX->sigchld_selfpipe_efd)) {
-rc = libxl__ev_fd_modify(gc, &CTX->sigchld_selfpipe_efd, 0);
-if (rc)
-libxl__ev_fd_deregister(gc, &CTX->sigchld_selfpipe_efd);
-}
+libxl__ev_fd_deregister(gc, &CTX->sigchld_selfpipe_efd);
}
int libxl__sigchld_needed(libxl__gc *gc) /* non-reentrant, idempotent */
--
1.7.10.4
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Re: [Xen-devel] [PATCH 3/6] libxl: events: Deregister, don't just modify, sigchld pipe fd
On Fri, 2014-11-28 at 14:42 +, Ian Jackson wrote:
> Ian Campbell writes ("Re: [PATCH 3/6] libxl: events: Deregister, don't just
> modify, sigchld pipe fd"):
> > On Thu, 2014-11-27 at 18:27 +, Ian Jackson wrote:
> > > We want to have no fd events registered when we are idle. This
> > > implies that we must be able to deregister our interest in the sigchld
> > > self-pipe fd, not just modify to request no events.
> > >
> > > Signed-off-by: Ian Jackson
> >
> > Acked-by: Ian Campbell
> >
> > I think in principal there is now some redundant code in
> > libxl__sigchld_needed which calls modify to set POLLIN if the fd is not
> > registered. I think it's redundant because now the fd is registered iff
> > it is looking for POLLIN.
>
> You're right. (Although you mean `calls modify if the fd /is/
> registered'.)
Indeed.
> I wonder if it would be better to leave tidying that up until
> post-4.5, in case we are wrong.
Sure.
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Re: [Xen-devel] [PATCH 3/6] libxl: events: Deregister, don't just modify, sigchld pipe fd
Ian Campbell writes ("Re: [PATCH 3/6] libxl: events: Deregister, don't just
modify, sigchld pipe fd"):
> On Thu, 2014-11-27 at 18:27 +, Ian Jackson wrote:
> > We want to have no fd events registered when we are idle. This
> > implies that we must be able to deregister our interest in the sigchld
> > self-pipe fd, not just modify to request no events.
> >
> > Signed-off-by: Ian Jackson
>
> Acked-by: Ian Campbell
>
> I think in principal there is now some redundant code in
> libxl__sigchld_needed which calls modify to set POLLIN if the fd is not
> registered. I think it's redundant because now the fd is registered iff
> it is looking for POLLIN.
You're right. (Although you mean `calls modify if the fd /is/
registered'.)
I wonder if it would be better to leave tidying that up until
post-4.5, in case we are wrong.
Ian.
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Re: [Xen-devel] [PATCH 3/6] libxl: events: Deregister, don't just modify, sigchld pipe fd
On Thu, 2014-11-27 at 18:27 +, Ian Jackson wrote:
> We want to have no fd events registered when we are idle. This
> implies that we must be able to deregister our interest in the sigchld
> self-pipe fd, not just modify to request no events.
>
> Signed-off-by: Ian Jackson
Acked-by: Ian Campbell
I think in principal there is now some redundant code in
libxl__sigchld_needed which calls modify to set POLLIN if the fd is not
registered. I think it's redundant because now the fd is registered iff
it is looking for POLLIN.
> ---
> tools/libxl/libxl_fork.c |9 +
> 1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/tools/libxl/libxl_fork.c b/tools/libxl/libxl_fork.c
> index fa15095..144208a 100644
> --- a/tools/libxl/libxl_fork.c
> +++ b/tools/libxl/libxl_fork.c
> @@ -372,15 +372,8 @@ static void sigchld_user_remove(libxl_ctx *ctx) /*
> idempotent */
>
> void libxl__sigchld_notneeded(libxl__gc *gc) /* non-reentrant, idempotent */
> {
> -int rc;
> -
> sigchld_user_remove(CTX);
> -
> -if (libxl__ev_fd_isregistered(&CTX->sigchld_selfpipe_efd)) {
> -rc = libxl__ev_fd_modify(gc, &CTX->sigchld_selfpipe_efd, 0);
> -if (rc)
> -libxl__ev_fd_deregister(gc, &CTX->sigchld_selfpipe_efd);
> -}
> +libxl__ev_fd_deregister(gc, &CTX->sigchld_selfpipe_efd);
> }
>
> int libxl__sigchld_needed(libxl__gc *gc) /* non-reentrant, idempotent */
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[Xen-devel] [PATCH 3/6] libxl: events: Deregister, don't just modify, sigchld pipe fd
We want to have no fd events registered when we are idle. This
implies that we must be able to deregister our interest in the sigchld
self-pipe fd, not just modify to request no events.
Signed-off-by: Ian Jackson
---
tools/libxl/libxl_fork.c |9 +
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/tools/libxl/libxl_fork.c b/tools/libxl/libxl_fork.c
index fa15095..144208a 100644
--- a/tools/libxl/libxl_fork.c
+++ b/tools/libxl/libxl_fork.c
@@ -372,15 +372,8 @@ static void sigchld_user_remove(libxl_ctx *ctx) /*
idempotent */
void libxl__sigchld_notneeded(libxl__gc *gc) /* non-reentrant, idempotent */
{
-int rc;
-
sigchld_user_remove(CTX);
-
-if (libxl__ev_fd_isregistered(&CTX->sigchld_selfpipe_efd)) {
-rc = libxl__ev_fd_modify(gc, &CTX->sigchld_selfpipe_efd, 0);
-if (rc)
-libxl__ev_fd_deregister(gc, &CTX->sigchld_selfpipe_efd);
-}
+libxl__ev_fd_deregister(gc, &CTX->sigchld_selfpipe_efd);
}
int libxl__sigchld_needed(libxl__gc *gc) /* non-reentrant, idempotent */
--
1.7.10.4
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