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# HG changeset patch
# User Olaf Hering <olaf@aepfle.de>
# Date 1321804961 -3600
# Node ID 1e343a57860ea0d75d862076eec695b81219092e
# Parent e74c938d38518f6f6344c9bcc6b7c8916a073594
xenpaging: retry unpageable gfns

Nomination of gfns can fail, but may succeed later.
Thats the case for a guest that starts ballooned.

v2:
- print debug when clearing uncosumed happens

Signed-off-by: Olaf Hering <olaf@aepfle.de>

diff -r e74c938d3851 -r 1e343a57860e tools/xenpaging/policy_default.c
--- a/tools/xenpaging/policy_default.c
+++ b/tools/xenpaging/policy_default.c
@@ -32,6 +32,7 @@ static unsigned int i_mru;
static unsigned int mru_size;
static unsigned long *bitmap;
static unsigned long *unconsumed;
+static unsigned int unconsumed_cleared;
static unsigned long current_gfn;
static unsigned long max_pages;

@@ -87,8 +88,21 @@ int policy_choose_victim(xenpaging_t *pa
current_gfn++;
if ( current_gfn >= max_pages )
current_gfn = 0;
+ /* Could not nominate any gfn */
if ( wrap == current_gfn )
{
+ /* Count wrap arounds */
+ unconsumed_cleared++;
+ /* Force retry every few seconds (depends on poll() timeout) */
+ if ( unconsumed_cleared > 123)
+ {
+ /* Force retry of unconsumed gfns */
+ bitmap_clear(unconsumed, max_pages);
+ unconsumed_cleared = 0;
+ DPRINTF("clearing unconsumed, wrap %lx", wrap);
+ /* One more round before returning ENOSPC */
+ continue;
+ }
victim->gfn = INVALID_MFN;
return -ENOSPC;
}

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