diff options
author | David Chinner <dgc@sgi.com> | 2006-03-14 13:29:16 +1100 |
---|---|---|
committer | Nathan Scott <nathans@sgi.com> | 2006-03-14 13:29:16 +1100 |
commit | 01e1b69cfcdcfdd5b405165eaba29428f8b18a7c (patch) | |
tree | 3ca7e8d0047ff03ca532f39b0fc4cd50381e8ecc /fs/xfs | |
parent | 87cbc49cd4b773a972bce56c5dd09c4717f3285b (diff) | |
download | op-kernel-dev-01e1b69cfcdcfdd5b405165eaba29428f8b18a7c.zip op-kernel-dev-01e1b69cfcdcfdd5b405165eaba29428f8b18a7c.tar.gz |
[XFS] using a spinlock per cpu for superblock counter exclusion results in
a preēmpt counter overflow at 256p and above. Change the exclusion
mechanism to use atomic bit operations and busy wait loops to emulate the
spin lock exclusion mechanism but without the preempt count issues.
SGI-PV: 950027
SGI-Modid: xfs-linux-melb:xfs-kern:25338a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r-- | fs/xfs/linux-2.6/xfs_linux.h | 1 | ||||
-rw-r--r-- | fs/xfs/xfs_mount.c | 37 | ||||
-rw-r--r-- | fs/xfs/xfs_mount.h | 4 |
3 files changed, 28 insertions, 14 deletions
diff --git a/fs/xfs/linux-2.6/xfs_linux.h b/fs/xfs/linux-2.6/xfs_linux.h index 9fdc14cf..bd88ccb 100644 --- a/fs/xfs/linux-2.6/xfs_linux.h +++ b/fs/xfs/linux-2.6/xfs_linux.h @@ -75,6 +75,7 @@ #include <linux/sort.h> #include <linux/cpu.h> #include <linux/notifier.h> +#include <linux/delay.h> #include <asm/page.h> #include <asm/div64.h> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index a64110b..d62aee0 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -1746,10 +1746,7 @@ xfs_icsb_cpu_notify( case CPU_UP_PREPARE: /* Easy Case - initialize the area and locks, and * then rebalance when online does everything else for us. */ - spin_lock_init(&cntp->icsb_lock); - cntp->icsb_icount = 0; - cntp->icsb_ifree = 0; - cntp->icsb_fdblocks = 0; + memset(cntp, 0, sizeof(xfs_icsb_cnts_t)); break; case CPU_ONLINE: xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0); @@ -1769,9 +1766,7 @@ xfs_icsb_cpu_notify( mp->m_sb.sb_ifree += cntp->icsb_ifree; mp->m_sb.sb_fdblocks += cntp->icsb_fdblocks; - cntp->icsb_icount = 0; - cntp->icsb_ifree = 0; - cntp->icsb_fdblocks = 0; + memset(cntp, 0, sizeof(xfs_icsb_cnts_t)); xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, XFS_ICSB_SB_LOCKED); xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, XFS_ICSB_SB_LOCKED); @@ -1800,7 +1795,7 @@ xfs_icsb_init_counters( for_each_online_cpu(i) { cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i); - spin_lock_init(&cntp->icsb_lock); + memset(cntp, 0, sizeof(xfs_icsb_cnts_t)); } /* * start with all counters disabled so that the @@ -1820,6 +1815,22 @@ xfs_icsb_destroy_counters( } } +STATIC inline void +xfs_icsb_lock_cntr( + xfs_icsb_cnts_t *icsbp) +{ + while (test_and_set_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags)) { + ndelay(1000); + } +} + +STATIC inline void +xfs_icsb_unlock_cntr( + xfs_icsb_cnts_t *icsbp) +{ + clear_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags); +} + STATIC inline void xfs_icsb_lock_all_counters( @@ -1830,7 +1841,7 @@ xfs_icsb_lock_all_counters( for_each_online_cpu(i) { cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i); - spin_lock(&cntp->icsb_lock); + xfs_icsb_lock_cntr(cntp); } } @@ -1843,7 +1854,7 @@ xfs_icsb_unlock_all_counters( for_each_online_cpu(i) { cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i); - spin_unlock(&cntp->icsb_lock); + xfs_icsb_unlock_cntr(cntp); } } @@ -2070,7 +2081,7 @@ xfs_icsb_modify_counters_int( again: cpu = get_cpu(); icsbp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, cpu), - spin_lock(&icsbp->icsb_lock); + xfs_icsb_lock_cntr(icsbp); if (unlikely(xfs_icsb_counter_disabled(mp, field))) goto slow_path; @@ -2104,7 +2115,7 @@ again: BUG(); break; } - spin_unlock(&icsbp->icsb_lock); + xfs_icsb_unlock_cntr(icsbp); put_cpu(); if (locked) XFS_SB_UNLOCK(mp, s); @@ -2120,7 +2131,7 @@ again: * manner. */ slow_path: - spin_unlock(&icsbp->icsb_lock); + xfs_icsb_unlock_cntr(icsbp); put_cpu(); /* need to hold superblock incase we need diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index 9d2ffbd..29cfcf0 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -280,9 +280,11 @@ typedef struct xfs_icsb_cnts { uint64_t icsb_fdblocks; uint64_t icsb_ifree; uint64_t icsb_icount; - spinlock_t icsb_lock; + unsigned long icsb_flags; } xfs_icsb_cnts_t; +#define XFS_ICSB_FLAG_LOCK (1 << 0) /* counter lock bit */ + #define XFS_ICSB_SB_LOCKED (1 << 0) /* sb already locked */ #define XFS_ICSB_LAZY_COUNT (1 << 1) /* accuracy not needed */ |