[Ocfs2-devel] [PATCH 3/3] ocfs2: modify reservation code to support discontigous localalloc

[Srinivas Eeda]

Currently reservation code assumes a bitmap given to it is all one contigous
chunk. This patch enhances it to handle a discontigous chunks. It adds new
fields m_bitmap_ext_cnt and m_bitmap_ext_arr. m_bitmap_ext_arr tracks the sizes
of each contigous free bits and m_bitmap_ext_cnt trackes number of
m_bitmap_ext_arr.

Signed-off-by: Srinivas Eeda srinivas.e...@oracle.com
---
 fs/ocfs2/reservations.c |   41 ++---
 fs/ocfs2/reservations.h |7 ++-
 2 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/fs/ocfs2/reservations.c b/fs/ocfs2/reservations.c
index 41ffd36..fea93d7 100644
--- a/fs/ocfs2/reservations.c
+++ b/fs/ocfs2/reservations.c
@@ -291,7 +291,15 @@ static void ocfs2_resmap_clear_all_resv(struct 
ocfs2_reservation_map *resmap)
}
 }
 
-void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
+void ocfs2_resmap_set_ext(struct ocfs2_reservation_map *resmap, int arr, u32 
sz)
+{
+   if (ocfs2_resmap_disabled(resmap))
+   return;
+
+   resmap-m_bitmap_ext_arr[arr] = sz;
+}
+
+void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap, u32 ext_cnt,
  unsigned int clen, char *disk_bitmap)
 {
if (ocfs2_resmap_disabled(resmap))
@@ -300,9 +308,21 @@ void ocfs2_resmap_restart(struct ocfs2_reservation_map 
*resmap,
spin_lock(resv_lock);
 
ocfs2_resmap_clear_all_resv(resmap);
+
+   /* free existing extent array */
+   if (resmap-m_bitmap_ext_arr)
+   kfree(resmap-m_bitmap_ext_arr);
+
resmap-m_bitmap_len = clen;
resmap-m_disk_bitmap = disk_bitmap;
 
+   resmap-m_bitmap_ext_cnt = ext_cnt;
+   resmap-m_bitmap_ext_arr = kmalloc((sizeof(u32) * ext_cnt), GFP_NOFS);
+   if (!resmap-m_bitmap_ext_arr) {
+   mlog_errno(-ENOMEM);
+   resmap-m_osb-osb_resv_level = 0;
+   }
+
spin_unlock(resv_lock);
 }
 
@@ -419,20 +439,26 @@ static int ocfs2_resmap_find_free_bits(struct 
ocfs2_reservation_map *resmap,
   unsigned int *rlen)
 {
void *bitmap = resmap-m_disk_bitmap;
-   unsigned int best_start, best_len = 0;
+   unsigned int best_start, len, ext, best_len = 0;
int offset, start, found;
 
trace_ocfs2_resmap_find_free_bits_begin(search_start, search_len,
wanted, resmap-m_bitmap_len);
 
-   found = best_start = best_len = 0;
-
+   found = best_start = best_len = ext = 0;
start = search_start;
+   len = resmap-m_bitmap_ext_arr[ext++];
while ((offset = ocfs2_find_next_zero_bit(bitmap, resmap-m_bitmap_len,
-start)) != -1) {
+ start)) != -1) {
/* Search reached end of the region */
if (offset = (search_start + search_len))
-   break;
+   goto out;
+
+   if (offset = len) {
+   len += resmap-m_bitmap_ext_arr[ext];
+   found = 1;
+   start = offset + 1;
+   }
 
if (offset == start) {
/* we found a zero */
@@ -450,9 +476,10 @@ static int ocfs2_resmap_find_free_bits(struct 
ocfs2_reservation_map *resmap,
}
 
if (found = wanted)
-   break;
+   goto out;
}
 
+out:
if (best_len == 0)
return 0;
 
diff --git a/fs/ocfs2/reservations.h b/fs/ocfs2/reservations.h
index 42c2b80..bb5e94f 100644
--- a/fs/ocfs2/reservations.h
+++ b/fs/ocfs2/reservations.h
@@ -56,6 +56,8 @@ struct ocfs2_reservation_map {
u32 m_bitmap_len;   /* Number of valid
 * bits available */
 
+   u32 m_bitmap_ext_cnt;
+   u32 *m_bitmap_ext_arr;
struct list_headm_lru;  /* LRU of reservations
 * structures. */
 
@@ -94,6 +96,9 @@ void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
 int ocfs2_resmap_init(struct ocfs2_super *osb,
  struct ocfs2_reservation_map *resmap);
 
+void ocfs2_resmap_set_ext(struct ocfs2_reservation_map *resmap, int arr,
+ u32 sz);
+
 /**
  * ocfs2_resmap_restart() - restart a reservation bitmap
  * @resmap: reservations bitmap
@@ -107,7 +112,7 @@ int ocfs2_resmap_init(struct ocfs2_super *osb,
  * reservations. A future version will recalculate existing
  * reservations based on the new bitmap.
  */
-void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
+void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap, u32 ext_cnt,
  unsigned int clen, char *disk_bitmap);
 
 /**
-- 
1.5.4.3

Re: [Ocfs2-devel] [PATCH 3/3] ocfs2: modify reservation code to support discontigous localalloc

[Joel Becker]

On Mon, May 07, 2012 at 04:21:30PM -0700, Srinivas Eeda wrote:
 Currently reservation code assumes a bitmap given to it is all one contigous
 chunk. This patch enhances it to handle a discontigous chunks. It adds new
 fields m_bitmap_ext_cnt and m_bitmap_ext_arr. m_bitmap_ext_arr tracks the 
 sizes
 of each contigous free bits and m_bitmap_ext_cnt trackes number of
 m_bitmap_ext_arr.
 
 Signed-off-by: Srinivas Eeda srinivas.e...@oracle.com

Hi Srini,
A patch like this should come before the feature patch.  Once
this code can treat the old single-range bitmap as a one-element
multiple-range bitmap, you can add the multiple-range change easily.

 +void ocfs2_resmap_set_ext(struct ocfs2_reservation_map *resmap, int arr, u32 
 sz)
 +{
 + if (ocfs2_resmap_disabled(resmap))
 + return;
 +
 + resmap-m_bitmap_ext_arr[arr] = sz;
 +}

I don't see this function called anywhere.  And please don't use
needless abbreviations.  If you want to say ocfs2_resmap_set_extent(),
write it out.  I don't quite get the arguments, and since it isn't
called, I can't figure out how they are used.

Joel

-- 

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 that we are to stand by the president, right or wrong, is not only
 unpatriotic and servile, but is morally treasonable to the American
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http://www.jlbec.org/
jl...@evilplan.org

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