Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=8fb870df5a1f261294b833dd807bcba3bacface6
Commit: 8fb870df5a1f261294b833dd807bcba3bacface6
Parent: 49defc015ff58fda46a3afa3462dfdfa69bc8401
Author: David Woodhouse <[EMAIL PROTECTED]>
AuthorDate: Sat Oct 6 15:12:58 2007 -0400
Committer: David Woodhouse <[EMAIL PROTECTED]>
CommitDate: Sat Oct 6 15:12:58 2007 -0400
[JFFS2] Trigger garbage collection when very_dirty_list size becomes
excessive
With huge amounts of free space, we weren't bothering to GC for while a
while, and pathological numbers of obsolete nodes were accumulating,
seriously affecting performance on NAND flash (OLPC trac #3978)
Signed-off-by: David Woodhouse <[EMAIL PROTECTED]>
---
fs/jffs2/build.c | 10 ++++++++++
fs/jffs2/jffs2_fs_sb.h | 2 ++
fs/jffs2/nodemgmt.c | 14 ++++++++++++--
3 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c
index 0ca2fff..8c27c12 100644
--- a/fs/jffs2/build.c
+++ b/fs/jffs2/build.c
@@ -285,6 +285,14 @@ static void jffs2_calc_trigger_levels(struct jffs2_sb_info
*c)
than actually making progress? */
c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;
+ /* What number of 'very dirty' eraseblocks do we allow before we
+ trigger the GC thread even if we don't _need_ the space. When we
+ can't mark nodes obsolete on the medium, the old dirty nodes cause
+ performance problems because we have to inspect and discard them. */
+ c->vdirty_blocks_gctrigger = c->resv_blocks_gcmerge;
+ if (jffs2_can_mark_obsolete(c))
+ c->vdirty_blocks_gctrigger *= 10;
+
/* If there's less than this amount of dirty space, don't bother
trying to GC to make more space. It'll be a fruitless task */
c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);
@@ -303,6 +311,8 @@ static void jffs2_calc_trigger_levels(struct jffs2_sb_info
*c)
c->resv_blocks_gcbad,
c->resv_blocks_gcbad*c->sector_size/1024);
dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n",
c->nospc_dirty_size);
+ dbg_fsbuild("Very dirty blocks before GC triggered: %d\n",
+ c->vdirty_blocks_gctrigger);
}
int jffs2_do_mount_fs(struct jffs2_sb_info *c)
diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
index ae99cd7..3a2197f 100644
--- a/fs/jffs2/jffs2_fs_sb.h
+++ b/fs/jffs2/jffs2_fs_sb.h
@@ -69,6 +69,8 @@ struct jffs2_sb_info {
uint8_t resv_blocks_gctrigger; /* ... wake up the GC thread */
uint8_t resv_blocks_gcbad; /* ... pick a block from the bad_list
to GC */
uint8_t resv_blocks_gcmerge; /* ... merge pages when garbage
collecting */
+ /* Number of 'very dirty' blocks before we trigger immediate GC */
+ uint8_t vdirty_blocks_gctrigger;
uint32_t nospc_dirty_size;
diff --git a/fs/jffs2/nodemgmt.c b/fs/jffs2/nodemgmt.c
index 5b49bff..1b79534 100644
--- a/fs/jffs2/nodemgmt.c
+++ b/fs/jffs2/nodemgmt.c
@@ -722,6 +722,8 @@ int jffs2_thread_should_wake(struct jffs2_sb_info *c)
{
int ret = 0;
uint32_t dirty;
+ int nr_very_dirty = 0;
+ struct jffs2_eraseblock *jeb;
if (c->unchecked_size) {
D1(printk(KERN_DEBUG "jffs2_thread_should_wake():
unchecked_size %d, checked_ino #%d\n",
@@ -743,8 +745,16 @@ int jffs2_thread_should_wake(struct jffs2_sb_info *c)
(dirty > c->nospc_dirty_size))
ret = 1;
- D1(printk(KERN_DEBUG "jffs2_thread_should_wake(): nr_free_blocks %d,
nr_erasing_blocks %d, dirty_size 0x%x: %s\n",
- c->nr_free_blocks, c->nr_erasing_blocks, c->dirty_size,
ret?"yes":"no"));
+ list_for_each_entry(jeb, &c->very_dirty_list, list) {
+ nr_very_dirty++;
+ if (nr_very_dirty == c->vdirty_blocks_gctrigger) {
+ ret = 1;
+ D1(break);
+ }
+ }
+
+ D1(printk(KERN_DEBUG "jffs2_thread_should_wake(): nr_free_blocks %d,
nr_erasing_blocks %d, dirty_size 0x%x, vdirty_blocks %d: %s\n",
+ c->nr_free_blocks, c->nr_erasing_blocks, c->dirty_size,
nr_very_dirty, ret?"yes":"no"));
return ret;
}
-
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