Re: RE: [PATCH net 0/2] Revert the 'socket_alloc' life cycle change

[SeongJae Park]

On Tue, 5 May 2020 13:44:42 +0100 Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:

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> On Tue, May 05, 2020 at 09:28:39AM +0200, SeongJae Park wrote:
> > From: SeongJae Park <sjpark@xxxxxxxxx>
> >
> > The commit 6d7855c54e1e ("sockfs: switch to ->free_inode()") made the
> > deallocation of 'socket_alloc' to be done asynchronously using RCU, as
> > same to 'sock.wq'.  And the following commit 333f7909a857 ("coallocate
> > socket_sq with socket itself") made those to have same life cycle.
> >
> > The changes made the code much more simple, but also made 'socket_alloc'
> > live longer than before.  For the reason, user programs intensively
> > repeating allocations and deallocations of sockets could cause memory
> > pressure on recent kernels.
> >
> > To avoid the problem, this commit reverts the changes.
> 
> Is it "could cause" or is it "have been actually observed to"?

Actually observed.  Sorry for lack of that explanation.  Could you please refer
to this link?
https://lore.kernel.org/netdev/20200505115402.25768-1-sjpark@xxxxxxxxxx/


Thanks,
SeongJae Park