Re: [PATCH] Remove unnecessary mmap in cpg

[Rongqing Li <rongqing.li@xxxxxxxxxxxxx>]

Could I backport this patch to corosync 1.4.3?

I backport it to 1.4.3, and then run the openais self test case,
and many test case failed.


-Roy

On 05/21/2013 09:01 AM, Rongqing Li wrote:
> Ok, I will test it soon.
> Thanks
>
> -Roy
>
>
> On 05/20/2013 09:57 PM, Jan Friesse wrote:
> > Code for zero-copy in cpg does following mmaps:
> > - Mmap anonymous, private memory to some address (-> malloc)
> > - Mmap shared memory of fd to address returned by first mmap
> >    (effectively shadows first mapping)
> >
> > This is not necessary and only one mapping is needed.
> >
> > Signed-off-by: Jan Friesse <jfriesse@xxxxxxxxxx>
> > ---
> >   exec/cpg.c |   18 +++---------------
> >   lib/cpg.c  |   19 ++++---------------
> >   2 files changed, 7 insertions(+), 30 deletions(-)
> >
> > diff --git a/exec/cpg.c b/exec/cpg.c
> > index 695f311..bfc3813 100644
> > --- a/exec/cpg.c
> > +++ b/exec/cpg.c
> > @@ -1603,7 +1603,6 @@ memory_map (
> >       void **buf)
> >   {
> >       int32_t fd;
> > -    void *addr_orig;
> >       void *addr;
> >       int32_t res;
> >
> > @@ -1620,20 +1619,9 @@ memory_map (
> >           goto error_close_unlink;
> >       }
> >
> > -    addr_orig = mmap (NULL, bytes, PROT_NONE,
> > -        MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> > +    addr = mmap (NULL, bytes, PROT_READ | PROT_WRITE,
> > +        MAP_SHARED, fd, 0);
> >
> > -    if (addr_orig == MAP_FAILED) {
> > -        goto error_close_unlink;
> > -    }
> > -
> > -    addr = mmap (addr_orig, bytes, PROT_READ | PROT_WRITE,
> > -        MAP_FIXED | MAP_SHARED, fd, 0);
> > -
> > -    if (addr != addr_orig) {
> > -        munmap(addr_orig, bytes);
> > -        goto error_close_unlink;
> > -    }
> >   #ifdef MADV_NOSYNC
> >       madvise(addr, bytes, MADV_NOSYNC);
> >   #endif
> > @@ -1642,7 +1630,7 @@ memory_map (
> >       if (res) {
> >           return (-1);
> >       }
> > -    *buf = addr_orig;
> > +    *buf = addr;
> >       return (0);
> >
> >   error_close_unlink:
> > diff --git a/lib/cpg.c b/lib/cpg.c
> > index b96df4e..f0ac593 100644
> > --- a/lib/cpg.c
> > +++ b/lib/cpg.c
> > @@ -730,7 +730,6 @@ static int
> >   memory_map (char *path, const char *file, void **buf, size_t bytes)
> >   {
> >       int32_t fd;
> > -    void *addr_orig;
> >       void *addr;
> >       int32_t res;
> >       char *buffer;
> > @@ -772,28 +771,18 @@ retry_write:
> >       }
> >       free (buffer);
> >
> > -    addr_orig = mmap (NULL, bytes, PROT_NONE,
> > -        MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> > +    addr = mmap (NULL, bytes, PROT_READ | PROT_WRITE,
> > +        MAP_SHARED, fd, 0);
> >
> > -    if (addr_orig == MAP_FAILED) {
> > -        goto error_close_unlink;
> > -    }
> > -
> > -    addr = mmap (addr_orig, bytes, PROT_READ | PROT_WRITE,
> > -        MAP_FIXED | MAP_SHARED, fd, 0);
> > -
> > -    if (addr != addr_orig) {
> > -        goto error_close_unlink;
> > -    }
> >   #ifdef MADV_NOSYNC
> > -    madvise(addr_orig, bytes, MADV_NOSYNC);
> > +    madvise(addr, bytes, MADV_NOSYNC);
> >   #endif
> >
> >       res = close (fd);
> >       if (res) {
> >           return (-1);
> >       }
> > -    *buf = addr_orig;
> > +    *buf = addr;
> >
> >       return 0;

--
Best Reagrds,
Roy | RongQing Li
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