Re: [Xen-devel] [PATCH] tools/xenstore: try to get minimum thread stack size for watch thread

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Thu, Feb 22, 2018 at 06:53:28PM +0000, Wei Liu wrote:
> On Thu, Feb 22, 2018 at 07:44:22PM +0100, Juergen Gross wrote:
> > On 22/02/18 18:28, Wei Liu wrote:
> > > On Thu, Feb 22, 2018 at 02:53:35PM +0100, Juergen Gross wrote:
> > >> When creating a pthread in xs_watch() try to get the minimal needed
> > >> size of the thread from glibc instead of using a constant. This avoids
> > >> problems when the library is used in programs with large per-thread
> > >> memory.
> > >>
> > >> Use dlsym() to get the pointer to __pthread_get_minstack() in order to
> > >> avoid linkage problems and fall back to the current constant size if
> > >> not found.
> > >>
> > >> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> > >> ---
> > >> Only compile tested. Jim, can you please verify this patch is solving
> > >> your original problem?
> > >> ---
> > >>  tools/xenstore/Makefile |  4 ++++
> > >>  tools/xenstore/xs.c     | 19 ++++++++++++++++++-
> > >>  2 files changed, 22 insertions(+), 1 deletion(-)
> > >>
> > >> diff --git a/tools/xenstore/Makefile b/tools/xenstore/Makefile
> > >> index 2b99d2bc1b..fb6c73e297 100644
> > >> --- a/tools/xenstore/Makefile
> > >> +++ b/tools/xenstore/Makefile
> > >> @@ -100,6 +100,10 @@ libxenstore.so.$(MAJOR): 
> > >> libxenstore.so.$(MAJOR).$(MINOR)
> > >>          ln -sf $< $@
> > >>  
> > >>  xs.opic: CFLAGS += -DUSE_PTHREAD
> > >> +ifeq ($(CONFIG_Linux),y)
> > >> +xs.opic: CFLAGS += -DUSE_DLSYM
> > >> +xs.opic: LDFLAGS += -ldl
> > >> +endif
> > >>  
> > >>  libxenstore.so.$(MAJOR).$(MINOR): xs.opic xs_lib.opic
> > >>          $(CC) $(LDFLAGS) $(PTHREAD_LDFLAGS) -Wl,$(SONAME_LDFLAG) 
> > >> -Wl,libxenstore.so.$(MAJOR) $(SHLIB_LDFLAGS) -o $@ $^ 
> > >> $(LDLIBS_libxentoolcore) $(SOCKET_LIBS) $(PTHREAD_LIBS) $(APPEND_LDFLAGS)
> > >> diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c
> > >> index abffd9cd80..8372f5b1a4 100644
> > >> --- a/tools/xenstore/xs.c
> > >> +++ b/tools/xenstore/xs.c
> > >> @@ -47,6 +47,11 @@ struct xs_stored_msg {
> > >>  
> > >>  #include <pthread.h>
> > >>  
> > >> +#ifdef USE_DLSYM
> > >> +#define __USE_GNU
> > > 
> > > Where does this come from? DLSYM(3) says _GNU_SOURCE (which we already
> > > have).
> > 
> > On my machine build failed, so I looked into the header...
> > 
> 
> Does putting _GNU_SOURCE at the beginning of that file before all
> headers solve the issue? I don't think we want to use an internal
> definition.

And I was wrong about "we already have _GNU_SOURCE" bit in my previous
email. At least not in the file you modified.

Wei.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel