NFS: Use cond_resched_lock() to reduce latencies in the commit scans
Ensure that we conditionally drop the inode->i_lock when it is safe to do so in the commit loops. We do so after locking the nfs_page, but before removing it from the commit list. We can then use list_safe_reset_next to recover the loop after the lock is retaken. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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parent
5ae67c4fee
commit
3b3be88d67
3 changed files with 20 additions and 10 deletions
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@ -936,7 +936,8 @@ static struct pnfs_layout_segment *find_only_write_lseg(struct inode *inode)
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}
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static int
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filelayout_scan_ds_commit_list(struct nfs4_fl_commit_bucket *bucket, int max)
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filelayout_scan_ds_commit_list(struct nfs4_fl_commit_bucket *bucket, int max,
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spinlock_t *lock)
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{
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struct list_head *src = &bucket->written;
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struct list_head *dst = &bucket->committing;
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@ -946,6 +947,8 @@ filelayout_scan_ds_commit_list(struct nfs4_fl_commit_bucket *bucket, int max)
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list_for_each_entry_safe(req, tmp, src, wb_list) {
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if (!nfs_lock_request(req))
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continue;
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if (cond_resched_lock(lock))
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list_safe_reset_next(req, tmp, wb_list);
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nfs_request_remove_commit_list(req);
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clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
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nfs_list_add_request(req, dst);
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@ -959,7 +962,8 @@ filelayout_scan_ds_commit_list(struct nfs4_fl_commit_bucket *bucket, int max)
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/* Move reqs from written to committing lists, returning count of number moved.
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* Note called with i_lock held.
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*/
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static int filelayout_scan_commit_lists(struct inode *inode, int max)
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static int filelayout_scan_commit_lists(struct inode *inode, int max,
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spinlock_t *lock)
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{
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struct pnfs_layout_segment *lseg;
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struct nfs4_filelayout_segment *fl;
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@ -972,7 +976,8 @@ static int filelayout_scan_commit_lists(struct inode *inode, int max)
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if (fl->commit_through_mds)
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goto out_done;
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for (i = 0; i < fl->number_of_buckets && max != 0; i++) {
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cnt = filelayout_scan_ds_commit_list(&fl->commit_buckets[i], max);
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cnt = filelayout_scan_ds_commit_list(&fl->commit_buckets[i],
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max, lock);
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max -= cnt;
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rv += cnt;
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}
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@ -97,7 +97,7 @@ struct pnfs_layoutdriver_type {
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void (*mark_request_commit) (struct nfs_page *req,
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struct pnfs_layout_segment *lseg);
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void (*clear_request_commit) (struct nfs_page *req);
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int (*scan_commit_lists) (struct inode *inode, int max);
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int (*scan_commit_lists) (struct inode *inode, int max, spinlock_t *lock);
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int (*commit_pagelist)(struct inode *inode, struct list_head *mds_pages, int how);
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/*
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@ -294,14 +294,14 @@ pnfs_clear_request_commit(struct nfs_page *req)
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}
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static inline int
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pnfs_scan_commit_lists(struct inode *inode, int max)
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pnfs_scan_commit_lists(struct inode *inode, int max, spinlock_t *lock)
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{
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struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
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int ret;
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if (ld == NULL || ld->scan_commit_lists == NULL)
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return 0;
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ret = ld->scan_commit_lists(inode, max);
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ret = ld->scan_commit_lists(inode, max, lock);
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if (ret != 0)
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set_bit(NFS_INO_PNFS_COMMIT, &NFS_I(inode)->flags);
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return ret;
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@ -419,7 +419,7 @@ pnfs_clear_request_commit(struct nfs_page *req)
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}
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static inline int
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pnfs_scan_commit_lists(struct inode *inode, int max)
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pnfs_scan_commit_lists(struct inode *inode, int max, spinlock_t *lock)
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{
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return 0;
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}
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@ -561,7 +561,8 @@ nfs_need_commit(struct nfs_inode *nfsi)
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/* i_lock held by caller */
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static int
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nfs_scan_commit_list(struct list_head *src, struct list_head *dst, int max)
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nfs_scan_commit_list(struct list_head *src, struct list_head *dst, int max,
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spinlock_t *lock)
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{
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struct nfs_page *req, *tmp;
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int ret = 0;
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@ -569,6 +570,8 @@ nfs_scan_commit_list(struct list_head *src, struct list_head *dst, int max)
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list_for_each_entry_safe(req, tmp, src, wb_list) {
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if (!nfs_lock_request(req))
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continue;
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if (cond_resched_lock(lock))
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list_safe_reset_next(req, tmp, wb_list);
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nfs_request_remove_commit_list(req);
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nfs_list_add_request(req, dst);
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ret++;
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@ -596,8 +599,10 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst)
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if (nfsi->ncommit > 0) {
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const int max = INT_MAX;
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ret = nfs_scan_commit_list(&nfsi->commit_list, dst, max);
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ret += pnfs_scan_commit_lists(inode, max - ret);
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ret = nfs_scan_commit_list(&nfsi->commit_list, dst, max,
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&inode->i_lock);
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ret += pnfs_scan_commit_lists(inode, max - ret,
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&inode->i_lock);
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}
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spin_unlock(&inode->i_lock);
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return ret;
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