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| author | David Chinner <dgc@sgi.com> | 2008-04-10 12:18:39 +1000 |
|---|---|---|
| committer | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2008-04-18 11:50:22 +1000 |
| commit | 114d23aae51233b2bc62d8e2a632bcb55de1953d (patch) | |
| tree | 39aa3e7e6dd32c39a416e34c4a663cb329315685 /fs/xfs/xfs_log_priv.h | |
| parent | 2abdb8c88110bab78bfe17e51346e735560daa02 (diff) | |
| download | linux-114d23aae51233b2bc62d8e2a632bcb55de1953d.tar.gz | |
[XFS] Per iclog callback chain lock
Rather than use the icloglock for protecting the iclog completion callback chain, use a new per-iclog lock so that walking the callback chain doesn't require holding a global lock. This reduces contention on the icloglock during transaction commit and log I/O completion by reducing the number of times we need to hold the global icloglock during these operations. SGI-PV: 978729 SGI-Modid: xfs-linux-melb:xfs-kern:30770a Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_log_priv.h')
| -rw-r--r-- | fs/xfs/xfs_log_priv.h | 33 |
1 files changed, 26 insertions, 7 deletions
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h index 01c63db25a1d..104b623aa082 100644 --- a/fs/xfs/xfs_log_priv.h +++ b/fs/xfs/xfs_log_priv.h @@ -324,6 +324,19 @@ typedef struct xlog_rec_ext_header { * - ic_offset is the current number of bytes written to in this iclog. * - ic_refcnt is bumped when someone is writing to the log. * - ic_state is the state of the iclog. + * + * Because of cacheline contention on large machines, we need to separate + * various resources onto different cachelines. To start with, make the + * structure cacheline aligned. The following fields can be contended on + * by independent processes: + * + * - ic_callback_* + * - ic_refcnt + * - fields protected by the global l_icloglock + * + * so we need to ensure that these fields are located in separate cachelines. + * We'll put all the read-only and l_icloglock fields in the first cacheline, + * and move everything else out to subsequent cachelines. */ typedef struct xlog_iclog_fields { sv_t ic_forcesema; @@ -332,18 +345,23 @@ typedef struct xlog_iclog_fields { struct xlog_in_core *ic_prev; struct xfs_buf *ic_bp; struct log *ic_log; - xfs_log_callback_t *ic_callback; - xfs_log_callback_t **ic_callback_tail; -#ifdef XFS_LOG_TRACE - struct ktrace *ic_trace; -#endif int ic_size; int ic_offset; - atomic_t ic_refcnt; int ic_bwritecnt; ushort_t ic_state; char *ic_datap; /* pointer to iclog data */ -} xlog_iclog_fields_t; +#ifdef XFS_LOG_TRACE + struct ktrace *ic_trace; +#endif + + /* Callback structures need their own cacheline */ + spinlock_t ic_callback_lock ____cacheline_aligned_in_smp; + xfs_log_callback_t *ic_callback; + xfs_log_callback_t **ic_callback_tail; + + /* reference counts need their own cacheline */ + atomic_t ic_refcnt ____cacheline_aligned_in_smp; +} xlog_iclog_fields_t ____cacheline_aligned_in_smp; typedef union xlog_in_core2 { xlog_rec_header_t hic_header; @@ -366,6 +384,7 @@ typedef struct xlog_in_core { #define ic_bp hic_fields.ic_bp #define ic_log hic_fields.ic_log #define ic_callback hic_fields.ic_callback +#define ic_callback_lock hic_fields.ic_callback_lock #define ic_callback_tail hic_fields.ic_callback_tail #define ic_trace hic_fields.ic_trace #define ic_size hic_fields.ic_size |