| Message ID | 20221013224151.300-2-jonathan.derrick@linux.dev (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Bitmap percentage flushing | expand |
On 10/13/2022 4:41 PM, Jonathan Derrick wrote: > Add a mechanism to allow bitmap unplugging and flushing to wait until it > has surpassed a defined threshold of dirty chunks. This allows certain > high I/O write workloads to make good forward progress between bitmap > updates or provide reliable bitmap consistency. The default behavior is > previous behavior of always unplugging when called. > > Signed-off-by: Jonathan Derrick <jonathan.derrick@linux.dev> > --- > drivers/md/md-bitmap.c | 35 +++++++++++++++++++++++++++++++---- > drivers/md/md-bitmap.h | 1 + > drivers/md/md.h | 1 + > 3 files changed, 33 insertions(+), 4 deletions(-) > > diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c > index bf6dffadbe6f..c5c77f8371a8 100644 > --- a/drivers/md/md-bitmap.c > +++ b/drivers/md/md-bitmap.c > @@ -1004,7 +1004,7 @@ static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block) > /* this gets called when the md device is ready to unplug its underlying > * (slave) device queues -- before we let any writes go down, we need to > * sync the dirty pages of the bitmap file to disk */ > -void md_bitmap_unplug(struct bitmap *bitmap) > +static void __md_bitmap_unplug(struct bitmap *bitmap) > { > unsigned long i; > int dirty, need_write; > @@ -1038,6 +1038,33 @@ void md_bitmap_unplug(struct bitmap *bitmap) > if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags)) > md_bitmap_file_kick(bitmap); > } > + > +/* > + * Conditional unplug based on user-defined parameter > + * Defaults to unconditional behavior > + */ > +void md_bitmap_unplug(struct bitmap *bitmap) > +{ > + unsigned int flush_threshold = bitmap->mddev->bitmap_info.flush_threshold; > + > + if (!flush_threshold) { > + __md_bitmap_unplug(bitmap); > + } else { > + struct bitmap_page *bp = bitmap->counts.bp; > + unsigned long pages = bitmap->counts.pages; > + unsigned long k, count = 0; > + > + for (k = 0; k < pages; k++) > + if (bp[k].map && !bp[k].hijacked) > + count += bp[k].count; > + > + if (count - bitmap->unplugged_count > flush_threshold) { > + bitmap->unplugged_count = count; > + md_bitmap_daemon_work(&bitmap->mddev->daemon_timer); I just noticed I call daemon_timer before adding it in 3/3 I'll fix that in v3 > + __md_bitmap_unplug(bitmap); > + } > + } > +} > EXPORT_SYMBOL(md_bitmap_unplug); > > static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed); > @@ -2012,9 +2039,9 @@ int md_bitmap_copy_from_slot(struct mddev *mddev, int slot, > for (i = 0; i < bitmap->storage.file_pages; i++) > if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING)) > set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE); > - md_bitmap_unplug(bitmap); > + __md_bitmap_unplug(bitmap); > } > - md_bitmap_unplug(mddev->bitmap); > + __md_bitmap_unplug(mddev->bitmap); > *low = lo; > *high = hi; > md_bitmap_free(bitmap); > @@ -2246,7 +2273,7 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks, > spin_unlock_irq(&bitmap->counts.lock); > > if (!init) { > - md_bitmap_unplug(bitmap); > + __md_bitmap_unplug(bitmap); > bitmap->mddev->pers->quiesce(bitmap->mddev, 0); > } > ret = 0; > diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h > index cfd7395de8fd..49a93d8ff307 100644 > --- a/drivers/md/md-bitmap.h > +++ b/drivers/md/md-bitmap.h > @@ -223,6 +223,7 @@ struct bitmap { > unsigned long daemon_lastrun; /* jiffies of last run */ > unsigned long last_end_sync; /* when we lasted called end_sync to > * update bitmap with resync progress */ > + unsigned long unplugged_count; /* last dirty count from md_bitmap_unplug */ > > atomic_t pending_writes; /* pending writes to the bitmap file */ > wait_queue_head_t write_wait; > diff --git a/drivers/md/md.h b/drivers/md/md.h > index b4e2d8b87b61..1a558cb18bd4 100644 > --- a/drivers/md/md.h > +++ b/drivers/md/md.h > @@ -501,6 +501,7 @@ struct mddev { > int external; > int nodes; /* Maximum number of nodes in the cluster */ > char cluster_name[64]; /* Name of the cluster */ > + unsigned int flush_threshold; /* how many dirty chunks between updates */ > } bitmap_info; > > atomic_t max_corr_read_errors; /* max read retries */
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index bf6dffadbe6f..c5c77f8371a8 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -1004,7 +1004,7 @@ static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block) /* this gets called when the md device is ready to unplug its underlying * (slave) device queues -- before we let any writes go down, we need to * sync the dirty pages of the bitmap file to disk */ -void md_bitmap_unplug(struct bitmap *bitmap) +static void __md_bitmap_unplug(struct bitmap *bitmap) { unsigned long i; int dirty, need_write; @@ -1038,6 +1038,33 @@ void md_bitmap_unplug(struct bitmap *bitmap) if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags)) md_bitmap_file_kick(bitmap); } + +/* + * Conditional unplug based on user-defined parameter + * Defaults to unconditional behavior + */ +void md_bitmap_unplug(struct bitmap *bitmap) +{ + unsigned int flush_threshold = bitmap->mddev->bitmap_info.flush_threshold; + + if (!flush_threshold) { + __md_bitmap_unplug(bitmap); + } else { + struct bitmap_page *bp = bitmap->counts.bp; + unsigned long pages = bitmap->counts.pages; + unsigned long k, count = 0; + + for (k = 0; k < pages; k++) + if (bp[k].map && !bp[k].hijacked) + count += bp[k].count; + + if (count - bitmap->unplugged_count > flush_threshold) { + bitmap->unplugged_count = count; + md_bitmap_daemon_work(&bitmap->mddev->daemon_timer); + __md_bitmap_unplug(bitmap); + } + } +} EXPORT_SYMBOL(md_bitmap_unplug); static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed); @@ -2012,9 +2039,9 @@ int md_bitmap_copy_from_slot(struct mddev *mddev, int slot, for (i = 0; i < bitmap->storage.file_pages; i++) if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING)) set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE); - md_bitmap_unplug(bitmap); + __md_bitmap_unplug(bitmap); } - md_bitmap_unplug(mddev->bitmap); + __md_bitmap_unplug(mddev->bitmap); *low = lo; *high = hi; md_bitmap_free(bitmap); @@ -2246,7 +2273,7 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks, spin_unlock_irq(&bitmap->counts.lock); if (!init) { - md_bitmap_unplug(bitmap); + __md_bitmap_unplug(bitmap); bitmap->mddev->pers->quiesce(bitmap->mddev, 0); } ret = 0; diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h index cfd7395de8fd..49a93d8ff307 100644 --- a/drivers/md/md-bitmap.h +++ b/drivers/md/md-bitmap.h @@ -223,6 +223,7 @@ struct bitmap { unsigned long daemon_lastrun; /* jiffies of last run */ unsigned long last_end_sync; /* when we lasted called end_sync to * update bitmap with resync progress */ + unsigned long unplugged_count; /* last dirty count from md_bitmap_unplug */ atomic_t pending_writes; /* pending writes to the bitmap file */ wait_queue_head_t write_wait; diff --git a/drivers/md/md.h b/drivers/md/md.h index b4e2d8b87b61..1a558cb18bd4 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -501,6 +501,7 @@ struct mddev { int external; int nodes; /* Maximum number of nodes in the cluster */ char cluster_name[64]; /* Name of the cluster */ + unsigned int flush_threshold; /* how many dirty chunks between updates */ } bitmap_info; atomic_t max_corr_read_errors; /* max read retries */
Add a mechanism to allow bitmap unplugging and flushing to wait until it has surpassed a defined threshold of dirty chunks. This allows certain high I/O write workloads to make good forward progress between bitmap updates or provide reliable bitmap consistency. The default behavior is previous behavior of always unplugging when called. Signed-off-by: Jonathan Derrick <jonathan.derrick@linux.dev> --- drivers/md/md-bitmap.c | 35 +++++++++++++++++++++++++++++++---- drivers/md/md-bitmap.h | 1 + drivers/md/md.h | 1 + 3 files changed, 33 insertions(+), 4 deletions(-)