diff options
Diffstat (limited to 'tools/xenpaging')
-rw-r--r-- | tools/xenpaging/policy_default.c | 57 |
1 files changed, 41 insertions, 16 deletions
diff --git a/tools/xenpaging/policy_default.c b/tools/xenpaging/policy_default.c index 7563720092..4648456031 100644 --- a/tools/xenpaging/policy_default.c +++ b/tools/xenpaging/policy_default.c @@ -80,33 +80,58 @@ int policy_init(struct xenpaging *paging) unsigned long policy_choose_victim(struct xenpaging *paging) { xc_interface *xch = paging->xc_handle; - unsigned long wrap = current_gfn; + unsigned long i; - do + /* One iteration over all possible gfns */ + for ( i = 0; i < max_pages; i++ ) { + /* Try next gfn */ current_gfn++; + + /* Restart on wrap */ if ( current_gfn >= max_pages ) current_gfn = 0; - /* Could not nominate any gfn */ - if ( wrap == current_gfn ) + + if ( (current_gfn & (BITS_PER_LONG - 1)) == 0 ) { - paging->use_poll_timeout = 1; - /* Count wrap arounds */ - unconsumed_cleared++; - /* Force retry every few seconds (depends on poll() timeout) */ - if ( unconsumed_cleared > 123) + /* All gfns busy */ + if ( ~bitmap[current_gfn >> ORDER_LONG] == 0 || ~unconsumed[current_gfn >> ORDER_LONG] == 0 ) { - /* 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 */ + current_gfn += BITS_PER_LONG; + i += BITS_PER_LONG; continue; } - return INVALID_MFN; } + + /* gfn busy */ + if ( test_bit(current_gfn, bitmap) ) + continue; + + /* gfn already tested */ + if ( test_bit(current_gfn, unconsumed) ) + continue; + + /* gfn found */ + break; + } + + /* Could not nominate any gfn */ + if ( i >= max_pages ) + { + /* No more pages, wait in poll */ + paging->use_poll_timeout = 1; + /* Count wrap arounds */ + unconsumed_cleared++; + /* Force retry every few seconds (depends on poll() timeout) */ + if ( unconsumed_cleared > 123) + { + /* Force retry of unconsumed gfns on next call */ + bitmap_clear(unconsumed, max_pages); + unconsumed_cleared = 0; + DPRINTF("clearing unconsumed, current_gfn %lx", current_gfn); + } + return INVALID_MFN; } - while ( test_bit(current_gfn, bitmap) || test_bit(current_gfn, unconsumed) ); set_bit(current_gfn, unconsumed); return current_gfn; |