[Xen-devel] Is noncached_write() in xc_domain_save() actually do

To:	xen-devel@xxxxxxxxxxxxxxxxxxx
Subject:	[Xen-devel] Is noncached_write() in xc_domain_save() actually doing what it says?
From:	"Mike Sun" <msun@xxxxxxxxxx>
Date:	Wed, 7 Jan 2009 22:25:10 -0500
Delivery-date:	Wed, 07 Jan 2009 19:25:48 -0800
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Hi,

I'm curious if noncached_write() (from xc_domain_save.c) is actually
doing writes without adding to the file system cache.  From what I
see, it's doing a write_exact(), then calling discard_file_cache()
without a flush, and ostensibly relying on the posix_fadvise64(...,
POSIX_FADV_DONTNEED) call to remove those written pages from the file
cache... but from what I understand, the POSIX_FADV_DONTNEED call
won't be able to remove those pages unless they have already been
flushed to disk.

Am I misunderstanding this?

Thanks,
Mike

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[Xen-devel] Is noncached_write() in xc_domain_save() actually doing what