[lvm-devel] [PATCH 1 of 11] LVM: agk allocation changes
Alasdair G Kergon
agk at redhat.com
Wed Mar 24 02:40:00 UTC 2010
On Fri, Mar 12, 2010 at 01:44:52PM -0600, Jon Brassow wrote:
> Still, people can test these patches as long as they don't stress the
> '--alloc anywhere' cases.
Latest version of this patch. Still not properly unit tested.
Alasdair
Index: lib/metadata/lv_manip.c
===================================================================
RCS file: /cvs/lvm2/LVM2/lib/metadata/lv_manip.c,v
retrieving revision 1.212
diff -u -p -r1.212 lv_manip.c
--- lib/metadata/lv_manip.c 23 Mar 2010 22:30:19 -0000 1.212
+++ lib/metadata/lv_manip.c 24 Mar 2010 02:33:51 -0000
@@ -985,6 +985,13 @@ static int _check_contiguous(struct cmd_
return 1;
}
+/* FIXME In future if this function is called multiple times with
+ * ALLOC_ANYWHERE after aborted allocation attempts, pv maps will need
+ * re-sorting.
+ * Walk all pv_areas and if remaining != count, set remaining =
+ * count and reinsert_reduced_pv_area.
+ */
+
/*
* Choose sets of parallel areas to use, respecting any constraints.
*/
@@ -999,12 +1006,13 @@ static int _find_parallel_space(struct a
struct pv_list *pvl;
unsigned already_found_one = 0;
unsigned contiguous = 0, cling = 0, preferred_count = 0;
- unsigned ix;
+ unsigned ix, last_ix;
unsigned ix_offset = 0; /* Offset for non-preferred allocations */
unsigned ix_log_offset; /* Offset to start of areas to use for log */
unsigned too_small_for_log_count; /* How many too small for log? */
uint32_t max_parallel; /* Maximum extents to allocate */
uint32_t next_le;
+ uint32_t required; /* Extents we're trying to obtain from this area */
struct seg_pvs *spvs;
struct dm_list *parallel_pvs;
uint32_t free_pes;
@@ -1062,6 +1070,9 @@ static int _find_parallel_space(struct a
}
}
+do {
+ /* Safety check to detect when ALLOC_ANYWHERE made no further progress. */
+ last_ix = ix;
/*
* Put the smallest area of each PV that is at least the
* size we need into areas array. If there isn't one
@@ -1089,6 +1100,7 @@ static int _find_parallel_space(struct a
already_found_one = 0;
/* First area in each list is the largest */
+// retry_pv:
dm_list_iterate_items(pva, &pvm->areas) {
if (contiguous) {
if (prev_lvseg &&
@@ -1114,13 +1126,17 @@ static int _find_parallel_space(struct a
}
/* Is it big enough on its own? */
- if (pva->count * ah->area_multiple <
+ if (pva->remaining * ah->area_multiple <
max_parallel - *allocated &&
((!can_split && !ah->log_area_count) ||
(already_found_one &&
!(alloc == ALLOC_ANYWHERE))))
goto next_pv;
+ /*
+ * Except with ALLOC_ANYWHERE, replace first area with this
+ * one which is smaller but still big enough.
+ */
if (!already_found_one ||
alloc == ALLOC_ANYWHERE) {
ix++;
@@ -1133,11 +1149,27 @@ static int _find_parallel_space(struct a
*areas_ptr = dm_realloc(*areas_ptr, sizeof(**areas_ptr) * (*areas_size_ptr));
}
(*areas_ptr)[ix + ix_offset - 1] = pva;
+
+ /* Update amount remaining - effectively splitting an area into two or more parts */
+ if (alloc == ALLOC_ANYWHERE) {
+ required = (max_parallel - *allocated) / ah->area_multiple;
+ if (required >= pva->remaining)
+ pva->remaining = 0;
+ else {
+ pva->remaining -= required;
+ reinsert_reduced_pv_area(pva);
+// ALLOC_ANYWHERE alternative: don't retry the PV.
+// At the end of this loop, we have one area per PV. If we haven't enough, repeat the whole loop (all PVs) taking the next largest from each.
+ // goto retry_pv; TEMP REMOVAL
+ }
+ }
}
next_pv:
if (ix >= *areas_size_ptr)
break;
}
+} while(ix < *areas_size_ptr && alloc == ALLOC_ANYWHERE && last_ix != ix);
+
if ((contiguous || cling) && (preferred_count < ix_offset))
break;
@@ -1174,7 +1206,6 @@ static int _find_parallel_space(struct a
if (ix + ix_offset < ah->area_count +
(log_needs_allocating ? ah->log_area_count +
too_small_for_log_count : 0))
- /* FIXME With ALLOC_ANYWHERE, need to split areas */
break;
if (!_alloc_parallel_area(ah, max_parallel, *areas_ptr, allocated,
Index: lib/metadata/pv_map.c
===================================================================
RCS file: /cvs/lvm2/LVM2/lib/metadata/pv_map.c,v
retrieving revision 1.35
diff -u -p -r1.35 pv_map.c
--- lib/metadata/pv_map.c 16 Mar 2010 14:37:38 -0000 1.35
+++ lib/metadata/pv_map.c 24 Mar 2010 02:33:51 -0000
@@ -24,19 +24,25 @@
*
* FIXME Cope with overlap.
*/
-static void _insert_area(struct dm_list *head, struct pv_area *a)
+static void _insert_area(struct dm_list *head, struct pv_area *a, unsigned reduced)
{
struct pv_area *pva;
-
- dm_list_iterate_items(pva, head) {
- if (a->count > pva->count)
+ uint32_t count = reduced ? a->remaining : a->count;
+
+ dm_list_iterate_items(pva, head)
+ if (count > pva->count)
break;
- }
dm_list_add(&pva->list, &a->list);
a->map->pe_count += a->count;
}
+static void _remove_area(struct pv_area *a)
+{
+ dm_list_del(&a->list);
+ a->map->pe_count -= a->count;
+}
+
static int _create_single_area(struct dm_pool *mem, struct pv_map *pvm,
uint32_t start, uint32_t length)
{
@@ -50,7 +56,8 @@ static int _create_single_area(struct dm
pva->map = pvm;
pva->start = start;
pva->count = length;
- _insert_area(&pvm->areas, pva);
+ pva->remaining = pva->count;
+ _insert_area(&pvm->areas, pva, 0);
return 1;
}
@@ -184,8 +191,7 @@ struct dm_list *create_pv_maps(struct dm
void consume_pv_area(struct pv_area *pva, uint32_t to_go)
{
- dm_list_del(&pva->list);
- pva->map->pe_count -= pva->count;
+ _remove_area(pva);
assert(to_go <= pva->count);
@@ -193,10 +199,21 @@ void consume_pv_area(struct pv_area *pva
/* split the area */
pva->start += to_go;
pva->count -= to_go;
- _insert_area(&pva->map->areas, pva);
+ pva->remaining = pva->count;
+ _insert_area(&pva->map->areas, pva, 0);
}
}
+/*
+ * Remove an area from list and reinsert it based on its new smaller size
+ * after a provisional allocation.
+ */
+void reinsert_reduced_pv_area(struct pv_area *pva)
+{
+ _remove_area(pva);
+ _insert_area(&pva->map->areas, pva, 1);
+}
+
uint32_t pv_maps_size(struct dm_list *pvms)
{
struct pv_map *pvm;
Index: lib/metadata/pv_map.h
===================================================================
RCS file: /cvs/lvm2/LVM2/lib/metadata/pv_map.h,v
retrieving revision 1.10
diff -u -p -r1.10 pv_map.h
--- lib/metadata/pv_map.h 3 Nov 2008 22:14:29 -0000 1.10
+++ lib/metadata/pv_map.h 24 Mar 2010 02:33:51 -0000
@@ -31,6 +31,8 @@ struct pv_area {
uint32_t start;
uint32_t count;
+ uint32_t remaining; /* Number of extents remaining unallocated during allocation number alloc_seqno */
+
struct dm_list list; /* pv_map.areas */
};
@@ -49,6 +51,7 @@ struct dm_list *create_pv_maps(struct dm
struct dm_list *allocatable_pvs);
void consume_pv_area(struct pv_area *area, uint32_t to_go);
+void reinsert_reduced_pv_area(struct pv_area *pva);
uint32_t pv_maps_size(struct dm_list *pvms);
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