diff options
author | NeilBrown <neilb@suse.de> | 2009-05-25 19:41:17 -0400 |
---|---|---|
committer | NeilBrown <neilb@suse.de> | 2009-05-25 19:41:17 -0400 |
commit | be512691036cc989c11d0f418187efbbf14468e6 (patch) | |
tree | 557b303a058fc3effdfc15a5cc08867fb0ee6889 /drivers | |
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>
Diffstat (limited to 'drivers')
-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) | |||
1097 | } | 1097 | } |
1098 | bitmap->allclean = 1; | 1098 | bitmap->allclean = 1; |
1099 | 1099 | ||
1100 | spin_lock_irqsave(&bitmap->lock, flags); | ||
1100 | for (j = 0; j < bitmap->chunks; j++) { | 1101 | for (j = 0; j < bitmap->chunks; j++) { |
1101 | bitmap_counter_t *bmc; | 1102 | bitmap_counter_t *bmc; |
1102 | spin_lock_irqsave(&bitmap->lock, flags); | 1103 | if (!bitmap->filemap) |
1103 | if (!bitmap->filemap) { | ||
1104 | /* error or shutdown */ | 1104 | /* error or shutdown */ |
1105 | spin_unlock_irqrestore(&bitmap->lock, flags); | ||
1106 | break; | 1105 | break; |
1107 | } | ||
1108 | 1106 | ||
1109 | page = filemap_get_page(bitmap, j); | 1107 | page = filemap_get_page(bitmap, j); |
1110 | 1108 | ||
@@ -1121,6 +1119,8 @@ void bitmap_daemon_work(struct bitmap *bitmap) | |||
1121 | write_page(bitmap, page, 0); | 1119 | write_page(bitmap, page, 0); |
1122 | bitmap->allclean = 0; | 1120 | bitmap->allclean = 0; |
1123 | } | 1121 | } |
1122 | spin_lock_irqsave(&bitmap->lock, flags); | ||
1123 | j |= (PAGE_BITS - 1); | ||
1124 | continue; | 1124 | continue; |
1125 | } | 1125 | } |
1126 | 1126 | ||
@@ -1181,9 +1181,10 @@ void bitmap_daemon_work(struct bitmap *bitmap) | |||
1181 | ext2_clear_bit(file_page_offset(j), paddr); | 1181 | ext2_clear_bit(file_page_offset(j), paddr); |
1182 | kunmap_atomic(paddr, KM_USER0); | 1182 | kunmap_atomic(paddr, KM_USER0); |
1183 | } | 1183 | } |
1184 | } | 1184 | } else |
1185 | spin_unlock_irqrestore(&bitmap->lock, flags); | 1185 | j |= PAGE_COUNTER_MASK; |
1186 | } | 1186 | } |
1187 | spin_unlock_irqrestore(&bitmap->lock, flags); | ||
1187 | 1188 | ||
1188 | /* now sync the final page */ | 1189 | /* now sync the final page */ |
1189 | if (lastpage != NULL) { | 1190 | if (lastpage != NULL) { |