Messages in this thread | | | Date | Mon, 26 Nov 2001 21:13:52 +0100 (CET) | From | Ingo Molnar <> | Subject | Re: [PATCH] Scalable page cache |
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On Mon, 26 Nov 2001, Christoph Hellwig wrote:
> - do_generic_file_read() now takes an additional integer parameter, > 'nonblock'. This one always is zero, though. Why do you break > the interface?
this is just the first, more important half of O_NONBLOCK support for block IO. Some servers (squid, TUX) rely on it for good performance.
> - there is a new global function, flush_inode_pages(). It is not > used at all. What is this one supposed to do?
it's for TUX's logfiles - the log file can grow to many gigabytes without polluting the pagecache. I think a new syscall should also use this: sys_flushfile(fd,offset,size), so that user-space servers can make use of this feature as well. If anyone is interested in actually using this new system-call then i can add those few additional lines. (other applications could use it as well, eg. clustered databases to invalidate database caches - but for this purpose the function has to become a bit more strict.)
> - file_send_actor() is no more static in mm/filemap.c. I'm perfectly > fine with that as I will need that for the UnixWare sendv64 emulation > in Linux-ABI, but again no user outside of filemap.c exists.
a TUX thing again, you are right, it makes no sense otherwise.
> - you change a number of parameters called 'offset' into 'index', > this makes sense to me, but doesn't really belong into this diff..
these are cleanups triggered by a bug i did: 'offset' was not consistently used as the byte granularity thing, it was used as a page granularity index once, which caused a bug in an earlier version of the patch.
> - due to the additional per-bucket spinlock the pagecache size > dramatically increases. Wouldn't it be a good idea to switch to > bootmem allocation so very big machines still can have the full > size, not limited by __get_free_pages failing?
for this purpose i wrote memarea_alloc() - bootmem IMO should remain a limited boot-time helper, not a full-blown allocator.
Ingo
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