2:09 p.m.
On Wed, 30 May 2018, Mike Snitzer wrote:
On Wed, May 30 2018 at 9:33am -0400,
Mikulas Patocka <mpatocka(a)redhat.com> wrote:
>
>
> On Wed, 30 May 2018, Mike Snitzer wrote:
>
> > On Wed, May 30 2018 at 9:21am -0400,
> > Mikulas Patocka <mpatocka(a)redhat.com> wrote:
> >
> > >
> > >
> > > On Wed, 30 May 2018, Mike Snitzer wrote:
> > >
> > > > That is really great news, can you submit an incremental patch that
> > > > layers ontop of the linux-dm.git 'dm-4.18' branch?
> > > >
> > > > Thanks,
> > > > Mike
> > >
> > > I've sent the current version that I have. I fixed the bugs that were
> > > reported here (missing DAX, dm_bufio_client_create, __branch_check__
> > > long->int truncation).
> >
> > OK, but a monolithic dm-writecache.c is no longer useful to me. I can
> > drop Arnd's gcc warning fix (with the idea that Ingo or Steve will take
> > your __branch_check__ patch). Not sure what the dm_bufio_client_create
> > fix is... must've missed a report about that.
> >
> > ANyway, point is we're on too a different phase of dm-writecache.c's
> > development. I've picked it up and am trying to get it ready for the
> > 4.18 merge window (likely opening Sunday). Therefore it needs to be in
> > a git tree, and incremental changes overlayed. I cannot be rebasing at
> > this late stage in the 4.18 development window.
> >
> > Thanks,
> > Mike
>
> I downloaded dm-writecache from your git repository some times ago - but
> you changed a lot of useless things (i.e. reordering the fields in the
> structure) since that time - so, you'll have to merge the changes.
Fine I'll deal with it. reordering the fields eliminated holes in the
structure and reduced struct members spanning cache lines.
And what about this?
#define WC_MODE_PMEM(wc) ((wc)->pmem_mode)
The code that I had just allowed the compiler to optimize out
persistent-memory code if we have DM_WRITECACHE_ONLY_SSD defined - and you
deleted it.
Most architectures don't have persistent memory and the dm-writecache
driver could work in ssd-only mode on them. On these architectures, I
define
#define WC_MODE_PMEM(wc) false
- and the compiler will just automatically remove the tests for that
condition and the unused branch. It does also eliminate unused static
functions.
Mikulas