linux.git/fs/f2fs/segment.h, branch v3.11

f2fs: modify the number of issued pages to merge IOs

2013-04-30T03:07:32+00:00

When testing f2fs on an SSD, I found some 128 page IOs followed by 1 page IO
were issued by f2fs_write_node_pages.
This means that there were some mishandling flows which degrades performance.

Previous f2fs_write_node_pages determines the number of pages to be written,
nr_to_write, as follows.

1. The bio_get_nr_vecs returns 129 pages.
2. The bio_alloc makes a room for 128 pages.
3. The initial 128 pages go into one bio.
4. The existing bio is submitted, and a new bio is prepared for the last 1 page.
5. Finally, sync_node_pages submits the last 1 page bio.

The problem is from the use of bio_get_nr_vecs, so this patch replace it
with max_hw_blocks using queue_max_sectors.

Signed-off-by: Jaegeuk Kim

f2fs: fix typo mistakes

2013-04-09T10:01:03+00:00

Fix typo mistakes.
1. I think that it should be 'L' instead of 'V'.
2. and try to fix 'Front' instead of 'Frone'

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat 
Signed-off-by: Jaegeuk Kim

f2fs: change GC bitmaps to apply the section granularity

2013-04-03T08:27:49+00:00

This patch removes a bitmap for victim segments selected by foreground GC, and
modifies the other bitmap for victim segments selected by background GC.

1) foreground GC bitmap
 : We don't need to manage this, since we just only one previous victim section
   number instead of the whole victim history.
   The f2fs uses the victim section number in order not to allocate currently
   GC'ed section to current active logs.

2) background GC bitmap
 : This bitmap is used to avoid selecting victims repeatedly by background GCs.
   In addition, the victims are able to be selected by foreground GCs, since
   there is no need to read victim blocks during foreground GCs.

   By the fact that the foreground GC reclaims segments in a section unit, it'd
   be better to manage this bitmap based on the section granularity.

Reviewed-by: Namjae Jeon 
Signed-off-by: Jaegeuk Kim

f2fs: introduce TOTAL_SECS macro

2013-04-03T07:23:10+00:00

Let's use a macro to get the total number of sections.

Reviewed-by: Namjae Jeon 
Signed-off-by: Jaegeuk Kim

f2fs: do not use duplicate names in a macro

2013-04-03T07:22:44+00:00

A macro should not use duplicate parameter names.

Reviewed-by: Namjae Jeon 
Signed-off-by: Jaegeuk Kim

f2fs: fix overflow when calculating utilization on 32-bit

2013-03-08T01:02:56+00:00

Use div_u64 to fix overflow when calculating utilization.
*long int* is 4-bytes on 32-bit so (user blocks * 100) might be
overflow if disk size is over e.g. 512GB.

Signed-off-by: Changman Lee 
Reviewed-by: Namjae Jeon 
Signed-off-by: Jaegeuk Kim

f2fs: clarify and enhance the f2fs_gc flow

2013-02-11T22:15:02+00:00

This patch makes clearer the ambiguous f2fs_gc flow as follows.

1. Remove intermediate checkpoint condition during f2fs_gc
 (i.e., should_do_checkpoint() and GC_BLOCKED)

2. Remove unnecessary return values of f2fs_gc because of #1.
 (i.e., GC_NODE, GC_OK, etc)

3. Simplify write_checkpoint() because of #2.

4. Clarify the main f2fs_gc flow.
 o monitor how many freed sections during one iteration of do_garbage_collect().
 o do GC more without checkpoints if we can't get enough free sections.
 o do checkpoint once we've got enough free sections through forground GCs.

5. Adopt thread-logging (Slack-Space-Recycle) scheme more aggressively on data
  log types. See. get_ssr_segement()

Signed-off-by: Jaegeuk Kim

f2fs: optimize the return condition for has_not_enough_free_secs

2013-02-11T22:15:02+00:00

Instead of evaluating the free_sections and then deciding to return
true/false from that path. We can directly use the evaluation condition
for returning proper value.

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat 
Signed-off-by: Jaegeuk Kim

f2fs: make an accessor to get sections for particular block type

2013-02-11T22:15:02+00:00

Introduce accessor to get the sections based upon the block type
(node,dents...) and modify the functions : should_do_checkpoint,
has_not_enough_free_secs to use this accessor function to get
the node sections and dent sections.

Signed-off-by: Namjae Jeon 
Signed-off-by: Amit Sahrawat 
Signed-off-by: Jaegeuk Kim

f2fs: fix equation of has_not_enough_free_secs()

2012-12-28T02:24:10+00:00

Practically, has_not_enough_free_secs() should calculate with the numbers of
current node and directory data blocks together.
Actually the equation was implemented in need_to_flush().

So, this patch removes need_flush() and moves the equation into
has_not_enough_free_secs().

Signed-off-by: Jaegeuk Kim