Author: rmacklem Date: Mon Dec 18 22:55:19 2017 New Revision: 326952 URL: https://svnweb.freebsd.org/changeset/base/326952
Log: MFC: r326544 Avoid the overhead of acquiring a lock in nfsrv_checkgetattr() when there are no write delegations issued. manu@ reported on the freebsd-current@ mailing list that there was a significant performance hit in nfsrv_checkgetattr() caused by the acquisition/release of a state lock, even when there were no write delegations issued. This patch add a count of outstanding issued write delegations to the NFSv4 server. This count allows nfsrv_checkgetattr() to return without acquiring any lock when the count is 0, avoiding the performance hit for the case where no write delegations are issued. Modified: stable/11/sys/fs/nfsserver/nfs_nfsdstate.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/fs/nfsserver/nfs_nfsdstate.c ============================================================================== --- stable/11/sys/fs/nfsserver/nfs_nfsdstate.c Mon Dec 18 20:17:54 2017 (r326951) +++ stable/11/sys/fs/nfsserver/nfs_nfsdstate.c Mon Dec 18 22:55:19 2017 (r326952) @@ -93,6 +93,7 @@ static time_t nfsrvboottime; static int nfsrv_returnoldstateid = 0, nfsrv_clients = 0; static int nfsrv_clienthighwater = NFSRV_CLIENTHIGHWATER; static int nfsrv_nogsscallback = 0; +static volatile int nfsrv_writedelegcnt = 0; /* local functions */ static void nfsrv_dumpaclient(struct nfsclient *clp, @@ -1261,6 +1262,8 @@ nfsrv_freedeleg(struct nfsstate *stp) LIST_REMOVE(stp, ls_hash); LIST_REMOVE(stp, ls_list); LIST_REMOVE(stp, ls_file); + if ((stp->ls_flags & NFSLCK_DELEGWRITE) != 0) + nfsrv_writedelegcnt--; lfp = stp->ls_lfp; if (LIST_EMPTY(&lfp->lf_open) && LIST_EMPTY(&lfp->lf_lock) && LIST_EMPTY(&lfp->lf_deleg) && @@ -2905,6 +2908,7 @@ tryagain: new_deleg->ls_flags = (NFSLCK_DELEGWRITE | NFSLCK_READACCESS | NFSLCK_WRITEACCESS); *rflagsp |= NFSV4OPEN_WRITEDELEGATE; + nfsrv_writedelegcnt++; } else { new_deleg->ls_flags = (NFSLCK_DELEGREAD | NFSLCK_READACCESS); @@ -3035,6 +3039,7 @@ tryagain: new_deleg->ls_clp = clp; new_deleg->ls_filerev = filerev; new_deleg->ls_compref = nd->nd_compref; + nfsrv_writedelegcnt++; LIST_INSERT_HEAD(&lfp->lf_deleg, new_deleg, ls_file); LIST_INSERT_HEAD(NFSSTATEHASH(clp, new_deleg->ls_stateid), new_deleg, ls_hash); @@ -3092,6 +3097,7 @@ tryagain: new_deleg->ls_flags = (NFSLCK_DELEGWRITE | NFSLCK_READACCESS | NFSLCK_WRITEACCESS); *rflagsp |= NFSV4OPEN_WRITEDELEGATE; + nfsrv_writedelegcnt++; } else { new_deleg->ls_flags = (NFSLCK_DELEGREAD | NFSLCK_READACCESS); @@ -3168,6 +3174,7 @@ tryagain: NFSLCK_READACCESS | NFSLCK_WRITEACCESS); *rflagsp |= NFSV4OPEN_WRITEDELEGATE; + nfsrv_writedelegcnt++; } else { new_deleg->ls_flags = (NFSLCK_DELEGREAD | @@ -5297,6 +5304,8 @@ nfsrv_checkgetattr(struct nfsrv_descript *nd, vnode_t NFSCBGETATTR_ATTRBIT(attrbitp, &cbbits); if (!NFSNONZERO_ATTRBIT(&cbbits)) + goto out; + if (nfsrv_writedelegcnt == 0) goto out; /* _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"