e0b0ca983d
Currently there is no mechanism to inspect which dbufs are being cached by the system. There are some coarse counters in arcstats by they only give a rough idea of what's being cached. This patch aims to improve the current situation by adding a new dbufs kstat. When read this new kstat will walk all cached dbufs linked in to the dbuf_hash. For each dbuf it will dump detailed information about the buffer. It will also dump additional information about the referenced arc buffer and its related dnode. This provides a more complete view in to exactly what is being cached. With this generic infrastructure in place utilities can be written to post-process the data to understand exactly how the caching is working. For example, the data could be processed to show a list of all cached dnodes and how much space they're consuming. Or a similar list could be generated based on dnode type. Many other ways to interpret the data exist based on what kinds of questions you're trying to answer. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Prakash Surya <surya1@llnl.gov>
231 lines
6.1 KiB
C
231 lines
6.1 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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#include <sys/zfs_context.h>
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#include <sys/dbuf.h>
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#include <sys/dmu_objset.h>
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/*
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* Calculate the index of the arc header for the state, disabled by default.
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*/
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int zfs_dbuf_state_index = 0;
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/*
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* ==========================================================================
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* Dbuf Hash Read Routines
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* ==========================================================================
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*/
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typedef struct dbuf_stats_t {
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kmutex_t lock;
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kstat_t *kstat;
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dbuf_hash_table_t *hash;
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int idx;
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} dbuf_stats_t;
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static dbuf_stats_t dbuf_stats_hash_table;
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static int
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dbuf_stats_hash_table_headers(char *buf, size_t size)
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{
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size = snprintf(buf, size - 1,
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"%-88s | %-124s | %s\n"
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"%-16s %-8s %-8s %-8s %-8s %-8s %-8s %-5s %-5s %5s | "
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"%-5s %-5s %-6s %-8s %-6s %-8s %-12s "
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"%-6s %-6s %-6s %-6s %-6s %-8s %-8s %-8s %-5s | "
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"%-6s %-6s %-8s %-8s %-6s %-6s %-5s %-8s %-8s\n",
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"dbuf", "arcbuf", "dnode", "pool", "objset", "object", "level",
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"blkid", "offset", "dbsize", "meta", "state", "dbholds", "list",
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"atype", "index", "flags", "count", "asize", "access", "mru", "gmru",
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"mfu", "gmfu", "l2", "l2_dattr", "l2_asize", "l2_comp", "aholds",
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"dtype", "btype", "data_bs", "meta_bs", "bsize",
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"lvls", "dholds", "blocks", "dsize");
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buf[size] = '\0';
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return (0);
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}
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int
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__dbuf_stats_hash_table_data(char *buf, size_t size, dmu_buf_impl_t *db)
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{
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arc_buf_info_t abi = { 0 };
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dmu_object_info_t doi = { 0 };
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dnode_t *dn = DB_DNODE(db);
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if (db->db_buf)
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arc_buf_info(db->db_buf, &abi, zfs_dbuf_state_index);
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if (dn)
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__dmu_object_info_from_dnode(dn, &doi);
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size = snprintf(buf, size - 1,
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"%-16s %-8llu %-8lld %-8lld %-8lld %-8llu %-8llu %-5d %-5d %-5lu | "
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"%-5d %-5d %-6lld 0x%-6x %-6lu %-8llu %-12llu "
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"%-6lu %-6lu %-6lu %-6lu %-6lu %-8llu %-8llu %-8d %-5lu | "
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"%-6d %-6d %-8lu %-8lu %-6llu %-6lu %-5lu %-8llu %-8llu\n",
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/* dmu_buf_impl_t */
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spa_name(dn->dn_objset->os_spa),
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(u_longlong_t)dmu_objset_id(db->db_objset),
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(longlong_t)db->db.db_object,
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(longlong_t)db->db_level,
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(longlong_t)db->db_blkid,
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(u_longlong_t)db->db.db_offset,
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(u_longlong_t)db->db.db_size,
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!!dbuf_is_metadata(db),
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db->db_state,
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(ulong_t)refcount_count(&db->db_holds),
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/* arc_buf_info_t */
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abi.abi_state_type,
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abi.abi_state_contents,
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(longlong_t)abi.abi_state_index,
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abi.abi_flags,
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(ulong_t)abi.abi_datacnt,
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(u_longlong_t)abi.abi_size,
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(u_longlong_t)abi.abi_access,
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(ulong_t)abi.abi_mru_hits,
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(ulong_t)abi.abi_mru_ghost_hits,
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(ulong_t)abi.abi_mfu_hits,
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(ulong_t)abi.abi_mfu_ghost_hits,
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(ulong_t)abi.abi_l2arc_hits,
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(u_longlong_t)abi.abi_l2arc_dattr,
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(u_longlong_t)abi.abi_l2arc_asize,
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abi.abi_l2arc_compress,
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(ulong_t)abi.abi_holds,
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/* dmu_object_info_t */
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doi.doi_type,
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doi.doi_bonus_type,
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(ulong_t)doi.doi_data_block_size,
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(ulong_t)doi.doi_metadata_block_size,
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(u_longlong_t)doi.doi_bonus_size,
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(ulong_t)doi.doi_indirection,
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(ulong_t)refcount_count(&dn->dn_holds),
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(u_longlong_t)doi.doi_fill_count,
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(u_longlong_t)doi.doi_max_offset);
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buf[size] = '\0';
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return (size);
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}
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static int
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dbuf_stats_hash_table_data(char *buf, size_t size, void *data)
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{
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dbuf_stats_t *dsh = (dbuf_stats_t *)data;
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dbuf_hash_table_t *h = dsh->hash;
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dmu_buf_impl_t *db;
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int length, error = 0;
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ASSERT3S(dsh->idx, >=, 0);
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ASSERT3S(dsh->idx, <=, h->hash_table_mask);
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memset(buf, 0, size);
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mutex_enter(DBUF_HASH_MUTEX(h, dsh->idx));
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for (db = h->hash_table[dsh->idx]; db != NULL; db = db->db_hash_next) {
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/*
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* Returning ENOMEM will cause the data and header functions
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* to be called with a larger scratch buffers.
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*/
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if (size < 512) {
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error = ENOMEM;
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break;
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}
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mutex_enter(&db->db_mtx);
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mutex_exit(DBUF_HASH_MUTEX(h, dsh->idx));
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length = __dbuf_stats_hash_table_data(buf, size, db);
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buf += length;
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size -= length;
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mutex_exit(&db->db_mtx);
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mutex_enter(DBUF_HASH_MUTEX(h, dsh->idx));
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}
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mutex_exit(DBUF_HASH_MUTEX(h, dsh->idx));
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return (error);
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}
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static void *
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dbuf_stats_hash_table_addr(kstat_t *ksp, loff_t n)
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{
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dbuf_stats_t *dsh = ksp->ks_private;
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ASSERT(MUTEX_HELD(&dsh->lock));
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if (n <= dsh->hash->hash_table_mask) {
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dsh->idx = n;
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return (dsh);
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}
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return (NULL);
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}
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static void
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dbuf_stats_hash_table_init(dbuf_hash_table_t *hash)
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{
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dbuf_stats_t *dsh = &dbuf_stats_hash_table;
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kstat_t *ksp;
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mutex_init(&dsh->lock, NULL, MUTEX_DEFAULT, NULL);
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dsh->hash = hash;
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ksp = kstat_create("zfs", 0, "dbufs", "misc",
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KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL);
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dsh->kstat = ksp;
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if (ksp) {
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ksp->ks_lock = &dsh->lock;
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ksp->ks_ndata = UINT32_MAX;
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ksp->ks_private = dsh;
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kstat_set_raw_ops(ksp, dbuf_stats_hash_table_headers,
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dbuf_stats_hash_table_data, dbuf_stats_hash_table_addr);
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kstat_install(ksp);
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}
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}
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static void
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dbuf_stats_hash_table_destroy(void)
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{
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dbuf_stats_t *dsh = &dbuf_stats_hash_table;
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kstat_t *ksp;
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ksp = dsh->kstat;
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if (ksp)
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kstat_delete(ksp);
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mutex_destroy(&dsh->lock);
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}
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void
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dbuf_stats_init(dbuf_hash_table_t *hash)
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{
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dbuf_stats_hash_table_init(hash);
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}
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void
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dbuf_stats_destroy(void)
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{
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dbuf_stats_hash_table_destroy();
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}
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#if defined(_KERNEL) && defined(HAVE_SPL)
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module_param(zfs_dbuf_state_index, int, 0644);
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MODULE_PARM_DESC(zfs_dbuf_state_index, "Calculate arc header index");
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#endif
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