diff options
author | Konstantin Belousov <kib@FreeBSD.org> | 2010-10-18 19:06:46 +0000 |
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committer | Konstantin Belousov <kib@FreeBSD.org> | 2010-10-18 19:06:46 +0000 |
commit | 223073fd1a00db13d0dd0cfb5a42e0912b765ee4 (patch) | |
tree | 1476a9a48c03cdc13771624d2bc864aaa56334dc /sys/nfsclient/nfs_nfsiod.c | |
parent | c4965cfc4441d419f9a14b3e5c2af268844e038f (diff) | |
download | src-223073fd1a00db13d0dd0cfb5a42e0912b765ee4.tar.gz src-223073fd1a00db13d0dd0cfb5a42e0912b765ee4.zip |
Do not synchronously start the nfsiod threads at all. The r212506
fixed the issues with file descriptor locks, but the same problems are
present for vnode lock/user map lock.
If the nfs_asyncio() cannot find the free nfsiod, schedule task to
create new nfsiod and return error. This causes fall back to the
synchronous i/o for nfs_strategy(), or does not start read at all in
the case of readahead. The caller that holds vnode and potentially
user map lock does not wait for kproc_create() to finish, preventing
the LORs.
The change effectively reverts r203072, because we never hand off the
request to newly created nfsiod thread anymore.
Reviewed by: jhb
Tested by: jhb, pluknet
MFC after: 3 weeks
Notes
Notes:
svn path=/head/; revision=214026
Diffstat (limited to 'sys/nfsclient/nfs_nfsiod.c')
-rw-r--r-- | sys/nfsclient/nfs_nfsiod.c | 95 |
1 files changed, 37 insertions, 58 deletions
diff --git a/sys/nfsclient/nfs_nfsiod.c b/sys/nfsclient/nfs_nfsiod.c index 5e2fbcc13ad8..fcb987e57677 100644 --- a/sys/nfsclient/nfs_nfsiod.c +++ b/sys/nfsclient/nfs_nfsiod.c @@ -76,16 +76,6 @@ static MALLOC_DEFINE(M_NFSSVC, "nfsclient_srvsock", "Nfs server structure"); static void nfssvc_iod(void *); -struct nfsiod_str { - STAILQ_ENTRY(nfsiod_str) ni_links; - int *ni_inst; - int ni_iod; - int ni_error; - int ni_done; -}; -static STAILQ_HEAD(, nfsiod_str) nfsiodhead = - STAILQ_HEAD_INITIALIZER(nfsiodhead); - static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON]; SYSCTL_DECL(_vfs_nfs); @@ -101,6 +91,8 @@ unsigned int nfs_iodmax = 20; /* Minimum number of nfsiod kthreads to keep as spares */ static unsigned int nfs_iodmin = 0; +static int nfs_nfsiodnew_sync(void); + static int sysctl_iodmin(SYSCTL_HANDLER_ARGS) { @@ -124,7 +116,7 @@ sysctl_iodmin(SYSCTL_HANDLER_ARGS) * than the new minimum, create some more. */ for (i = nfs_iodmin - nfs_numasync; i > 0; i--) - nfs_nfsiodnew(0); + nfs_nfsiodnew_sync(); out: mtx_unlock(&nfs_iod_mtx); return (0); @@ -170,68 +162,55 @@ SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0, sizeof (nfs_iodmax), sysctl_iodmax, "IU", "Max number of nfsiod kthreads"); +static int +nfs_nfsiodnew_sync(void) +{ + int error, i; + + mtx_assert(&nfs_iod_mtx, MA_OWNED); + for (i = 0; i < nfs_iodmax; i++) { + if (nfs_asyncdaemon[i] == 0) { + nfs_asyncdaemon[i] = 1; + break; + } + } + if (i == nfs_iodmax) + return (0); + mtx_unlock(&nfs_iod_mtx); + error = kproc_create(nfssvc_iod, nfs_asyncdaemon + i, NULL, + RFHIGHPID, 0, "nfsiod %d", i); + mtx_lock(&nfs_iod_mtx); + if (error == 0) { + nfs_numasync++; + nfs_iodwant[i] = NFSIOD_AVAILABLE; + } else + nfs_asyncdaemon[i] = 0; + return (error); +} + void nfs_nfsiodnew_tq(__unused void *arg, int pending) { - struct nfsiod_str *nip; mtx_lock(&nfs_iod_mtx); - while ((nip = STAILQ_FIRST(&nfsiodhead)) != NULL) { - STAILQ_REMOVE_HEAD(&nfsiodhead, ni_links); - mtx_unlock(&nfs_iod_mtx); - nip->ni_error = kproc_create(nfssvc_iod, nip->ni_inst, NULL, - RFHIGHPID, 0, "nfsiod %d", nip->ni_iod); - nip->ni_done = 1; - mtx_lock(&nfs_iod_mtx); - wakeup(nip); + while (pending > 0) { + pending--; + nfs_nfsiodnew_sync(); } mtx_unlock(&nfs_iod_mtx); } -int -nfs_nfsiodnew(int set_iodwant) +void +nfs_nfsiodnew(void) { - int error, i; - int newiod; - struct nfsiod_str *nip; - if (nfs_numasync >= nfs_iodmax) - return (-1); - newiod = -1; - for (i = 0; i < nfs_iodmax; i++) - if (nfs_asyncdaemon[i] == 0) { - nfs_asyncdaemon[i]++; - newiod = i; - break; - } - if (newiod == -1) - return (-1); - if (set_iodwant > 0) - nfs_iodwant[i] = NFSIOD_CREATED_FOR_NFS_ASYNCIO; - mtx_unlock(&nfs_iod_mtx); - nip = malloc(sizeof(*nip), M_TEMP, M_WAITOK | M_ZERO); - nip->ni_inst = nfs_asyncdaemon + i; - nip->ni_iod = newiod; - mtx_lock(&nfs_iod_mtx); - STAILQ_INSERT_TAIL(&nfsiodhead, nip, ni_links); + mtx_assert(&nfs_iod_mtx, MA_OWNED); taskqueue_enqueue(taskqueue_thread, &nfs_nfsiodnew_task); - while (!nip->ni_done) - mtx_sleep(nip, &nfs_iod_mtx, 0, "niwt", 0); - error = nip->ni_error; - free(nip, M_TEMP); - if (error) { - if (set_iodwant > 0) - nfs_iodwant[i] = NFSIOD_NOT_AVAILABLE; - return (-1); - } - nfs_numasync++; - return (newiod); } static void nfsiod_setup(void *dummy) { - int i; int error; TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin); @@ -240,8 +219,8 @@ nfsiod_setup(void *dummy) if (nfs_iodmin > NFS_MAXASYNCDAEMON) nfs_iodmin = NFS_MAXASYNCDAEMON; - for (i = 0; i < nfs_iodmin; i++) { - error = nfs_nfsiodnew(0); + while (nfs_numasync < nfs_iodmin) { + error = nfs_nfsiodnew_sync(); if (error == -1) panic("nfsiod_setup: nfs_nfsiodnew failed"); } |