Messages in this thread | | | Date | Wed, 14 Aug 2013 09:43:59 -0700 | From | Andi Kleen <> | Subject | Re: [PATCH v1 2/2] perf tools: add attr->mmap2 support |
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On Wed, Aug 14, 2013 at 12:30:08PM +0200, Stephane Eranian wrote: > On Wed, Aug 14, 2013 at 1:34 AM, Andi Kleen <ak@linux.intel.com> wrote: > > On Tue, Aug 13, 2013 at 01:55:57PM +0200, Stephane Eranian wrote: > >> This patch adds support for the new PERF_RECORD_MMAP2 > >> record type exposed by the kernel. This is an extended > >> PERF_RECORD_MMAP record. It adds for each file-backed > >> mapping the device major, minor number and the inode > >> number. This triplet uniquely identifies the source > >> of a file-backed mapping. It can be used to detect > >> identical virtual mappings between processes for instance. > > > > Can you also add the generation number please? > > That would make it even more unique. > > > I assume you're talkng about inode->i_generation, right?
Yes.
> I could add that one easily. I am surprised to see: > > mm/shmem.c: > static struct inode *shmem_get_inode(struct super_block *sb, const > struct inode *dir, > umode_t mode, dev_t dev, unsigned > long flags) > { > inode->i_generation = get_seconds(); > } > I am assuming that the uniqueness for SHM is coming from the SHMID and therefore > a poor quality i_generation is sufficient here.
Yes that's odd. But most file system should have a sensible generation number.
-Andi
-- ak@linux.intel.com -- Speaking for myself only
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