Messages in this thread |  | | | Date | Thu, 10 Oct 2002 15:39:19 +0200 (CEST) | | From | Giuliano Pochini <> | | Subject | Re: [PATCH] O_STREAMING - flag for optimal streaming I/O |
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> Look, the pagecache is already smart. New stuff will replace unusued > old stuff. On VM pressure, the pagecache will be pruned. Streaming I/O > is a fundamentally different problem in that the data is so large it > _continually_ thrashes the pagecache. Such I/O is sequential and > use-once. You end up with a permanent waste of memory (the cached > I/O).
When a process opens a file with O_STREAMING, it tells the kernel it will use the data only once, but it tells nothing about other tasks. If that process reads something which is already cached, then it must not drop it because someone other used it recently and IMHO pagecache only should be allowed to drop it.
> Let's prove we have a solution to this problem before going after > tangent ones.
If "solution" means "code", sorry, I can't help :(
Bye.
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