[Devel] [PATCH RHEL7 COMMIT] ploop: Read 10 BAT clusters on holes_bitmap population
Konstantin Khorenko
khorenko at virtuozzo.com
Wed Feb 5 12:55:18 MSK 2020
The commit is pushed to "branch-rh7-3.10.0-1062.7.1.vz7.130.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1062.7.1.vz7.130.15
------>
commit c1ce7a9def75a92300acaae269f0cfeba6200035
Author: Kirill Tkhai <ktkhai at virtuozzo.com>
Date: Wed Feb 5 12:55:18 2020 +0300
ploop: Read 10 BAT clusters on holes_bitmap population
This makes a batch and improves performance or BAT analyzing.
Now we submit up to 10 clusters at read and before wait of
request completion.
Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
Patchset description:
Possibility to batch page reads and batch on holes_bitmap population
Submit batch request up to 10 clusters (10Mb, 2560 pages)
during holes_bitmap population to speed up ploop mount
of big images.
https://jira.sw.ru/browse/PSBM-101246
Kirill Tkhai (4):
ploop: Teach dio_sync_io() work with many pages
ploop: Teach kaio_sync_io() work with many pages
ploop: Introduce .sync_read_many method
ploop: Read 10 BAT clusters on holes_bitmap population
---
drivers/block/ploop/fmt_ploop1.c | 86 +++++++++++++++++++++++++---------------
1 file changed, 55 insertions(+), 31 deletions(-)
diff --git a/drivers/block/ploop/fmt_ploop1.c b/drivers/block/ploop/fmt_ploop1.c
index 6745d29e53096..806f020f0bb7d 100644
--- a/drivers/block/ploop/fmt_ploop1.c
+++ b/drivers/block/ploop/fmt_ploop1.c
@@ -140,13 +140,36 @@ ploop1_compose(struct ploop_delta * delta, int nchunks, struct ploop_ctl_chunk *
return ploop_io_init(delta, nchunks, pc);
}
+static unsigned int parse_bat_page_for_hb(struct ploop_delta *delta,
+ struct ploop1_private *ph,
+ struct page *page,
+ unsigned int block)
+{
+ unsigned int i, off = block ? 0 : PLOOP_MAP_OFFSET;
+ u32 *index;
+
+ index = page_address(page);
+ for (i = off; i < INDEX_PER_PAGE && block + i - off < ph->nr_bat_entries; i++) {
+ if (index[i] != 0) {
+ unsigned int cluster = index[i] >> ploop_map_log(delta->plo);
+ /*
+ * On grow cluster above nr_clusters_in_bitmap may
+ * be assigned. Ignore it.
+ */
+ if (likely(cluster < ph->nr_clusters_in_bitmap))
+ ploop_clear_holes_bitmap_bit(cluster, delta);
+ }
+ }
+
+ return i - off;
+}
+
static int populate_holes_bitmap(struct ploop_delta *delta,
struct ploop1_private *ph)
{
- unsigned int block, nr_blocks, size, off, md_off;
- struct page *page;
+ unsigned int block, nr_blocks, md_off, count, nr_all_pages, size, consumed = 0;
+ struct page **pages;
sector_t sec;
- u32 *index;
int i, ret;
if (test_bit(PLOOP_S_NO_FALLOC_DISCARD, &delta->plo->state))
@@ -159,10 +182,18 @@ static int populate_holes_bitmap(struct ploop_delta *delta,
}
ret = -ENOMEM;
- page = alloc_page(GFP_KERNEL);
- if (!page)
+ /* Use multiplier 10 for bigger batch and better performance */
+ nr_all_pages = 10 * cluster_size_in_bytes(delta->plo) / PAGE_SIZE;
+ pages = kvzalloc(sizeof(struct page *) * nr_all_pages, GFP_KERNEL);
+ if (!pages)
return ret;
+ for (i = 0; i < nr_all_pages; i++) {
+ pages[i] = alloc_page(GFP_KERNEL);
+ if (!pages[i])
+ goto out;
+ }
+
/*
* Holes bitmap is map of clusters from start of file to maximum
* cluster, which may be refered by BAT.
@@ -177,7 +208,7 @@ static int populate_holes_bitmap(struct ploop_delta *delta,
delta->holes_bitmap = kvmalloc(size, GFP_KERNEL);
if (!delta->holes_bitmap)
- goto put_page;
+ goto out;
ph->nr_clusters_in_bitmap = nr_blocks;
memset(delta->holes_bitmap, 0xff, size);
/* Tail clusters are not available for allocation */
@@ -188,44 +219,37 @@ static int populate_holes_bitmap(struct ploop_delta *delta,
clear_bit(i, delta->holes_bitmap);
block = 0;
- while (block < nr_blocks) {
+ while (block < ph->nr_bat_entries) {
if (!ploop1_map_index(delta, block, &sec)) {
/*
* BAT area can address wider region, than disk size.
* This may be a result of shrinking large disk
* to a small size.
*/
- pr_info("ploop%u: bat is bigger than disk size\n",
+ pr_err("ploop%u: bat is bigger than disk size\n",
delta->plo->index);
- goto put_page;
+ goto out;
}
- ret = delta->io.ops->sync_read(&delta->io, page,
- 4096, 0, sec);
- if (ret)
- goto put_page;
-
- off = block ? 0 : PLOOP_MAP_OFFSET;
-
- index = page_address(page);
- for (i = off; i < INDEX_PER_PAGE && block + i - off < nr_blocks; i++) {
- if (index[i] != 0) {
- unsigned int cluster = index[i] >> ploop_map_log(delta->plo);
- /*
- * On grow cluster above nr_clusters_in_bitmap may
- * be assigned. Ignore it.
- */
- if (likely(cluster < ph->nr_clusters_in_bitmap))
- ploop_clear_holes_bitmap_bit(cluster, delta);
- }
+ /* Images with big BAT and small data may be shorter than nr_all_pages */
+ count = min_t(unsigned int, nr_all_pages,
+ (ph->l1_off << 9) / PAGE_SIZE - consumed);
+ ret = delta->io.ops->sync_read_many(&delta->io, pages, count, sec);
+ if (ret) {
+ pr_err("ploop: too short BAT\n");
+ goto out;
}
- block += (block ? INDEX_PER_PAGE : INDEX_PER_PAGE - PLOOP_MAP_OFFSET);
+ for (i = 0; i < count && block < ph->nr_bat_entries; i++)
+ block += parse_bat_page_for_hb(delta, ph, pages[i], block);
+ consumed += count;
}
ret = 0;
-
-put_page:
- put_page(page);
+out:
+ for (i = 0; i < nr_all_pages; i++)
+ if (pages[i])
+ put_page(pages[i]);
+ kvfree(pages);
return ret;
}
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