Messages in this thread | | | Date | Fri, 22 May 1998 13:50:47 +0200 | From | Marnix Coppens <> | Subject | Re: Swapping in 2.1.103? |
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Karl GünterWünsch wrote: >Jim Wilcoxson wrote: >> >> ..., but perhaps there could be something like "if a file has never >> been repositioned, then after it is closed, mark its file buffers so that >> they will be re-used before paging out non-buffer-cache pages". Also, >> sequentially accessing a large file shouldn't wipe out the buffer cache. >> If a file has never been positioned while reading/writing, there is a good >> chance that the data in the buffer cache, except for the page where the >> file pointer is (or future pages for read-ahead) will not be needed in the >> near future...
I may be totally clueless here, but what if you are working on a program, that (often indirectly) uses a *large* number of relatively small header files. Just strace the compiler and watch it open several hundred files in all. These files are used in a sequential fashion and have a short life span (open, quick read, close, repeat xxx times). If you are in a edit-compile-debug cycle, you don't want all these files to be thrown out as quickly as possible, on the contrary.
The (obvious) point is that the usage frequency matters far more than the occasional repositioning. Unless of course, you are talking about adding a new flag to the open mode (like NT's FILE_FLAG_NO_BUFFERING or FILE_FLAG_SEQUENTIAL_SCAN or FILE_FLAG_RANDOM_ACCESS), rather than modifying the default behaviour. Check Albert Cahalan's wish list.
Cheers,
Marnix Coppens
--- Reality is that which | Artificial Intelligence when you stop believing | stands no chance against in it doesn't go away. (Philip K. Dick) | Natural Stupidity.
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