On Wed, May 30, 2018 at 5:08 PM Qing Huang <qing.hu...@oracle.com> wrote:
>
>
>
> On 5/30/2018 1:50 PM, Eric Dumazet wrote:
> > On Wed, May 30, 2018 at 4:30 PM Qing Huang <qing.hu...@oracle.com> wrote:
> >>
> >>
> >> On 5/29/2018 9:11 PM, Eric Dumazet wrote:
> >>> Commit 1383cb8103bb ("mlx4_core: allocate ICM memory in page size chunks")
> >>> brought a regression caught in our regression suite, thanks to KASAN.
> >> If KASAN reported issue was really caused by smaller chunk sizes,
> >> changing allocation
> >> order dynamically will eventually hit the same issue.
> > Sigh, you have little idea of what your patch really did...
> >
> > The KASAN part only shows the tip of the iceberg, but our main concern
> > is an increase of memory overhead.
>
> Well, the commit log only mentioned KASAN and but the change here didn't
> seem to solve
> the issue.Can you elaborate ? My patch solves our problems. Both the memory overhead and KASAN splats are gone. > > > > > Alternative is to revert your patch, since we are now very late in 4.17 > > cycle. > > > > Memory usage has grown a lot with your patch, since each 4KB page needs a > > full > > struct mlx4_icm_chunk (256 bytes of overhead !) > > Going to smaller chunks will have some overhead. It depends on the > application though. > What's the total increased memory consumption in your env? As I explained, your patch adds 256 bytes of overhead per 4KB. Your changelog did not mentioned that at all, and we discovered this the hard way. That is pretty intolerable, and is a blocker for us, memory is precious.
