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authorJiro SEKIBA <jir@unicus.jp>2009-09-03 09:24:17 -0400
committerRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2009-09-14 05:27:15 -0400
commit1cf58fa840472ec7df6bf2312885949ebb308853 (patch)
tree2743a6ab63331703e6c9abbb714e2bf13744d009 /fs/nilfs2
parent43be0ec0387a5ccce2e064cb78502e7b2b4dd590 (diff)
nilfs2: shorten freeze period due to GC in write operation v3
This is a re-revised patch to shorten freeze period. This version include a fix of the bug Konishi-san mentioned last time. When GC is runnning, GC moves live block to difference segments. Copying live blocks into memory is done in a transaction, however it is not necessarily to be in the transaction. This patch will get the nilfs_ioctl_move_blocks() out from transaction lock and put it before the transaction. I ran sysbench fileio test against nilfs partition. I copied some DVD/CD images and created snapshot to create live blocks before starting the benchmark. Followings are summary of rc8 and rc8 w/ the patch of per-request statistics, which is min/max and avg. I ran each test three times and bellow is average of those numers. According to this benchmark result, average time is slightly degrated. However, worstcase (max) result is significantly improved. This can address a few seconds write freeze. - random write per-request performance of rc8 min 0.843ms max 680.406ms avg 3.050ms - random write per-request performance of rc8 w/ this patch min 0.843ms -> 100.00% max 380.490ms -> 55.90% avg 3.233ms -> 106.00% - sequential write per-request performance of rc8 min 0.736ms max 774.343ms avg 2.883ms - sequential write per-request performance of rc8 w/ this patch min 0.720ms -> 97.80% max 644.280ms-> 83.20% avg 3.130ms -> 108.50% -----8<-----8<-----nilfs_cleanerd.conf-----8<-----8<----- protection_period 150 selection_policy timestamp # timestamp in ascend order nsegments_per_clean 2 cleaning_interval 2 retry_interval 60 use_mmap log_priority info -----8<-----8<-----nilfs_cleanerd.conf-----8<-----8<----- Signed-off-by: Jiro SEKIBA <jir@unicus.jp> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Diffstat (limited to 'fs/nilfs2')
-rw-r--r--fs/nilfs2/ioctl.c26
-rw-r--r--fs/nilfs2/the_nilfs.h2
2 files changed, 21 insertions, 7 deletions
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 6ea5f872e2de..6572ea4bc4df 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -442,12 +442,6 @@ int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs,
442 const char *msg; 442 const char *msg;
443 int ret; 443 int ret;
444 444
445 ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], kbufs[0]);
446 if (ret < 0) {
447 msg = "cannot read source blocks";
448 goto failed;
449 }
450
451 ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], kbufs[1]); 445 ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], kbufs[1]);
452 if (ret < 0) { 446 if (ret < 0) {
453 /* 447 /*
@@ -548,7 +542,25 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
548 } 542 }
549 } 543 }
550 544
551 ret = nilfs_clean_segments(inode->i_sb, argv, kbufs); 545 /*
546 * nilfs_ioctl_move_blocks() will call nilfs_gc_iget(),
547 * which will operates an inode list without blocking.
548 * To protect the list from concurrent operations,
549 * nilfs_ioctl_move_blocks should be atomic operation.
550 */
551 if (test_and_set_bit(THE_NILFS_GC_RUNNING, &nilfs->ns_flags)) {
552 ret = -EBUSY;
553 goto out_free;
554 }
555
556 ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], kbufs[0]);
557 if (ret < 0)
558 printk(KERN_ERR "NILFS: GC failed during preparation: "
559 "cannot read source blocks: err=%d\n", ret);
560 else
561 ret = nilfs_clean_segments(inode->i_sb, argv, kbufs);
562
563 clear_nilfs_gc_running(nilfs);
552 564
553 out_free: 565 out_free:
554 while (--n >= 0) 566 while (--n >= 0)
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index 68e9626e3d44..20abd55881e0 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -37,6 +37,7 @@ enum {
37 THE_NILFS_LOADED, /* Roll-back/roll-forward has done and 37 THE_NILFS_LOADED, /* Roll-back/roll-forward has done and
38 the latest checkpoint was loaded */ 38 the latest checkpoint was loaded */
39 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ 39 THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
40 THE_NILFS_GC_RUNNING, /* gc process is running */
40}; 41};
41 42
42/** 43/**
@@ -195,6 +196,7 @@ static inline int nilfs_##name(struct the_nilfs *nilfs) \
195THE_NILFS_FNS(INIT, init) 196THE_NILFS_FNS(INIT, init)
196THE_NILFS_FNS(LOADED, loaded) 197THE_NILFS_FNS(LOADED, loaded)
197THE_NILFS_FNS(DISCONTINUED, discontinued) 198THE_NILFS_FNS(DISCONTINUED, discontinued)
199THE_NILFS_FNS(GC_RUNNING, gc_running)
198 200
199/* Minimum interval of periodical update of superblocks (in seconds) */ 201/* Minimum interval of periodical update of superblocks (in seconds) */
200#define NILFS_SB_FREQ 10 202#define NILFS_SB_FREQ 10