Hi, This is a revised patch to shorten freeze period. This version includes fixes of the bugs Konishi-san mentioned.
When GC is runnning, GC moves live block to difference segments. Copying live blocks into memory is done in a transaction, but 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 0.830ms -> 98.40% max 366.870ms -> 53.90% avg 3.170ms -> 103.90% - 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 0.726ms -> 100.50% max 695.976ms-> 72.80% avg 3.110ms -> 107.80% -----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 <[email protected]> --- fs/nilfs2/ioctl.c | 22 ++++++++++++++-------- fs/nilfs2/the_nilfs.h | 2 ++ 2 files changed, 16 insertions(+), 8 deletions(-) diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c index 6ea5f87..cc6ec4b 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, const char *msg; int ret; - ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], kbufs[0]); - if (ret < 0) { - msg = "cannot read source blocks"; - goto failed; - } - ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], kbufs[1]); if (ret < 0) { /* @@ -509,6 +503,12 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp, nsegs = argv[4].v_nmembs; if (argv[4].v_size != argsz[4]) return -EINVAL; + + nilfs = NILFS_SB(inode->i_sb)->s_nilfs; + + if (test_and_set_bit(THE_NILFS_GC_RUNNING, &nilfs->ns_flags)) + return -EBUSY; + /* * argv[4] points to segment numbers this ioctl cleans. We * use kmalloc() for its buffer because memory used for the @@ -519,8 +519,6 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp, if (IS_ERR(kbufs[4])) return PTR_ERR(kbufs[4]); - nilfs = NILFS_SB(inode->i_sb)->s_nilfs; - for (n = 0; n < 4; n++) { ret = -EINVAL; if (argv[n].v_size != argsz[n]) @@ -548,12 +546,20 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp, } } + ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], kbufs[0]); + if (ret < 0) { + printk(KERN_ERR "NILFS: GC failed during preparation: " + "cannot read source blocks: err=%d\n", ret); + goto out_free; + } + ret = nilfs_clean_segments(inode->i_sb, argv, kbufs); out_free: while (--n >= 0) vfree(kbufs[n]); kfree(kbufs[4]); + clear_nilfs_gc_running(nilfs); return ret; } diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index 1b9caaf..97ee569 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -37,6 +37,7 @@ enum { THE_NILFS_LOADED, /* Roll-back/roll-forward has done and the latest checkpoint was loaded */ THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */ + THE_NILFS_GC_RUNNING, /* gc process is running */ }; /** @@ -197,6 +198,7 @@ static inline int nilfs_##name(struct the_nilfs *nilfs) \ THE_NILFS_FNS(INIT, init) THE_NILFS_FNS(LOADED, loaded) THE_NILFS_FNS(DISCONTINUED, discontinued) +THE_NILFS_FNS(GC_RUNNING, gc_running) /* Minimum interval of periodical update of superblocks (in seconds) */ #define NILFS_SB_FREQ 10 -- 1.5.6.5 _______________________________________________ users mailing list [email protected] https://www.nilfs.org/mailman/listinfo/users
