On 20.01.25 6:50, Pavel Tikhomirov wrote:
On 12/6/24 05:55, Alexander Atanasov wrote:
From: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
Drop ploop_cluster_is_in_top_delta(), because
- it internally searches md on every call
- it takes read lock every time
https://virtuozzo.atlassian.net/browse/VSTOR-91817
Signed-off-by: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
---
drivers/md/dm-ploop-map.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index c89e28aa18f9..de885049e3f9 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -899,13 +899,14 @@ static void ploop_bat_write_complete(struct pio
*pio, void *piwb_ptr,
static int ploop_prepare_bat_update(struct ploop *ploop, struct
md_page *md,
enum piwb_type type)
{
- u32 i, off, last, *bat_entries;
+ u32 i, off, last, *bat_entries, clu;
struct ploop_index_wb *piwb;
bool is_last_page = true;
u32 page_id = md->id;
struct page *page;
struct pio *pio;
map_index_t *to;
+ u8 level;
piwb = kmalloc(sizeof(*piwb), GFP_NOIO);
if (!piwb)
@@ -928,6 +929,8 @@ static int ploop_prepare_bat_update(struct ploop
*ploop, struct md_page *md,
piwb->page_id = page_id;
to = piwb->kmpage;
+
+ read_lock_irq(&md->lock);
memcpy((void *)to, bat_entries, PAGE_SIZE);
/* Absolute number of first index in page (negative for page#0) */
@@ -946,10 +949,14 @@ static int ploop_prepare_bat_update(struct ploop
*ploop, struct md_page *md,
/* Copy BAT (BAT goes right after hdr, see .ctr) */
for (; i < last; i++) {
- if (ploop_cluster_is_in_top_delta(ploop, i + off))
- continue;
- to[i] = 0;
+ level = md->bat_levels[i];
Why do we assume that md page will not change when iterating from
PLOOP_MAP_OFFSET and until (ploop->nr_bat_entries - (page_id * PAGE_SIZE
/ sizeof(map_index_t) - PLOOP_MAP_OFFSET) ? If it's true, we need
explanation in commit message. If false, we need to update md each time
as ploop_cluster_is_in_top_delta did.
this can change on grow or shrink - but when such operation is in
progress, there are no pios in flight and pio submission is suspended -
so it can not change. Change is applied at the end of operation.
+ clu = READ_ONCE(bat_entries[i]);
+
+ if (clu == BAT_ENTRY_NONE || level < ploop_top_level(ploop))
+ to[i] = 0;
}
+ read_unlock_irq(&md->lock);
+
if (is_last_page) {
/* Fill tail of page with 0 */
for (i = last; i < PAGE_SIZE / sizeof(map_index_t); i++)
--
Regards,
Alexander Atanasov
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