Messages in this thread | | | Date | Thu, 7 Jun 2007 12:48:24 -0700 | From | Andrew Morton <> | Subject | Re: [RFC][PATCH] /proc/pid/maps doesn't match "ipcs -m" shmid |
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On Thu, 07 Jun 2007 10:06:37 -0700 Badari Pulavarty <pbadari@us.ibm.com> wrote:
> On Thu, 2007-06-07 at 12:43 -0400, Albert Cahalan wrote: > > On 6/7/07, Badari Pulavarty <pbadari@us.ibm.com> wrote: > > > > > BTW, I agree with Eric that its would be nice to use shmid as part > > > of name instead of forcing to be as inode number. It should be > > > possible for pmap to workout shmid from "key" or name. Isn't it ? > > > > It is not at all nice. > > > > 1. it's incompatible ABI breakage > > 2. where will you put the key then, in the inode? :-) > > Nope. Currently "key" is part of the name (but its not unique). > > > > > Changing to "SYSVID%d" is no good either. Look, people > > are ***parsing*** this stuff in /proc. The /proc filesystem > > is not some random sandbox to be playing in. > > > > Before you go messing with it, note that the device number > > also matters. (it's per-boot dynamic, but that's OK) > > That's how one knows that /SYSV00000000 is not just > > a regular file; sadly these didn't get a non-/ prefix. > > (and no you can't fix that now; it's way too late) > > > > Next time you feel like breaking an ABI, mind putting > > "LET'S BREAK AN ABI!" in the subject of your email? > > I am not breaking ABI. Its already broken in the current > mainline. I am trying to fix it by putting back the ino# > as shmid. Eric had a suggestion that, instead of depending > on the inode# to be shmid, we could embed shmid into name > (instead of "key" which is currently not unique). > > > BTW, I suspect this kind of thing also breaks: > > a. fuser, lsof, and other resource usage display tools > > b. various obscure emulators (similar to valgrind) > > If you strongly feel that "old" behaviour needs to be retained,
yup, we should put it back. The change was, afaik, accidental.
> here is the patch I originally suggested.
Confused. Will this one-liner fix all the userspace breakage to which Albert refers?
> Thanks, > Badari > > "ino#" in /proc/pid/maps used to match "ipcs -m" output for shared > memory (shmid). It was useful in debugging, but its changed recently. > This patch sets inode number to shared memory id to match /proc/pid/maps. > > Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> > > Index: linux-2.6.22-rc4/ipc/shm.c > =================================================================== > --- linux-2.6.22-rc4.orig/ipc/shm.c 2007-06-04 17:57:25.000000000 -0700 > +++ linux-2.6.22-rc4/ipc/shm.c 2007-06-06 08:23:57.000000000 -0700 > @@ -397,6 +397,7 @@ static int newseg (struct ipc_namespace > shp->shm_nattch = 0; > shp->id = shm_buildid(ns, id, shp->shm_perm.seq); > shp->shm_file = file; > + file->f_dentry->d_inode->i_ino = shp->id; > > ns->shm_tot += numpages; > shm_unlock(shp); > > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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