Re: [PATCH] Allow to disable shmem.o

[Hugh Dickins]

On Sun, 8 Aug 2004, Andrew Morton wrote:
> Hugh Dickins <hugh@xxxxxxxxxxx> wrote:
> >
> > But somehow I still prefer Matt's patch, which offers a lot more.
> 
> Me too - it's sneaky.
> 
> I suspect it's more SMp scalable than shmem.c too?

I bet it is (unless it falls into generic filepage overheads
which shmem is skating past e.g. attempts to readahead).

Though I hope not notably more so by the time I've finished
reworking shmem_getpage (was on the right track yesterday,
but other issues have intervened today).

They should both come down to find_get_page (find_lock_page in
shmem.c's case, only an issue when contention on same page),
alloc_page, add_to_page_cache: contention on tree_lock.

Its main deficiency (aside from the lack of swap use, which in
some contexts is a plus) is its lack of resource limiting.

Hugh

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