diff options
author | NeilBrown <neilb@suse.de> | 2009-05-26 09:41:17 +1000 |
---|---|---|
committer | NeilBrown <neilb@suse.de> | 2009-05-26 09:41:17 +1000 |
commit | be512691036cc989c11d0f418187efbbf14468e6 (patch) | |
tree | 557b303a058fc3effdfc15a5cc08867fb0ee6889 | |
parent | 2b69c83924396ad1eda36fdd267c9d2f360f5555 (diff) |
md: bitmap: improve bitmap maintenance code.
The code for checking which bits in the bitmap can be cleared
has 2 problems:
1/ it repeatedly takes and drops a spinlock, where it would make
more sense to just hold on to it most of the time.
2/ it doesn't make use of some opportunities to skip large sections
of the bitmap
This patch fixes those. It will only affect CPU consumption, not
correctness.
Signed-off-by: NeilBrown <neilb@suse.de>
-rw-r--r-- | drivers/md/bitmap.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index 47c68bc75a17..56df1cee8fb3 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -1097,14 +1097,12 @@ void bitmap_daemon_work(struct bitmap *bitmap) } bitmap->allclean = 1; + spin_lock_irqsave(&bitmap->lock, flags); for (j = 0; j < bitmap->chunks; j++) { bitmap_counter_t *bmc; - spin_lock_irqsave(&bitmap->lock, flags); - if (!bitmap->filemap) { + if (!bitmap->filemap) /* error or shutdown */ - spin_unlock_irqrestore(&bitmap->lock, flags); break; - } page = filemap_get_page(bitmap, j); @@ -1121,6 +1119,8 @@ void bitmap_daemon_work(struct bitmap *bitmap) write_page(bitmap, page, 0); bitmap->allclean = 0; } + spin_lock_irqsave(&bitmap->lock, flags); + j |= (PAGE_BITS - 1); continue; } @@ -1181,9 +1181,10 @@ void bitmap_daemon_work(struct bitmap *bitmap) ext2_clear_bit(file_page_offset(j), paddr); kunmap_atomic(paddr, KM_USER0); } - } - spin_unlock_irqrestore(&bitmap->lock, flags); + } else + j |= PAGE_COUNTER_MASK; } + spin_unlock_irqrestore(&bitmap->lock, flags); /* now sync the final page */ if (lastpage != NULL) { |