Take 3 -- I've moved the flushing/fadvise-ing code into a common routine
-- the only way I found to do this in line with other utilities was to
make it inline in xc_private.h (since this is the only file included in
both libxenctrl and libxenguest). The 'ifdef __linux__' stuff is now
confined to this routine which is better...
I've also left the fsync() in place -- I think it is necessary (and
certainly does no harm).
Simon
-----------------------------------
Reduce impact of saving/restoring/dumping large domains on Dom0 memory
usage by means of fadvise64() to tell the OS to discard the cache pages
used for the save/dump file.
-----Original Message-----
From: xen-...@lists.xensource.com [mailto:xen-devel-
boun...@lists.xensource.com] On Behalf Of Keir Fraser
Sent: Wednesday, February 21, 2007 10:10 AM
To: Graham, Simon; Keir Fraser; xen-...@lists.xensource.com
Subject: Re: [Xen-devel] [PATCH][TOOLS] Reducing
impactofdomainsave/restore/dump on Dom0
On 21/2/07 15:06, "Graham, Simon" <Simo...@stratus.com> wrote:
2. sync-then-advise is only done at the end of writing a file to
ensure
that all
of the cached pages are discarded. Whilst writing the file, I
only
fadvise
which triggers a write back and discards any clean pages up to
the
specified offset.
This is indeed a performance thing -- fsyncing on every write
makes
it very slow.
Do you need the fsync at all? It's possible that the kernel will
launder-then-discard the affected pages automatically, just from the
fadvise() alone.
-- Keir
21 messages in com.xensource.lists.xen-develRE: [Xen-devel] [PATCH][TOOLS] Reduci...
.patch