updated patch with Barath's suggestion of renaming it from
/sys/module/cifs/parameters/max_dir_cache to
/sys/module/cifs/parameters/dir_cache_timeout and also changed it so
if set to zero we disable
directory entry caching.
See attached.
On Sun, Aug 27, 2023 at 12:12 AM Steve French <smfrench@xxxxxxxxx> wrote:
>
> Currently with directory leases we cache directory contents for a fixed period
> of time (default 30 seconds) but for many workloads this is too short. Allow
> configuring the maximum amount of time directory entries are cached when a
> directory lease is held on that directory (and set default timeout to
> 60 seconds).
> Add module load parm "max_dir_cache"
>
> For example to set the timeout to 10 minutes you would do:
>
> echo 600 > /sys/module/cifs/parameters/max_dir_cache
>
> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
> ---
> fs/smb/client/cached_dir.c | 2 +-
> fs/smb/client/cifsfs.c | 12 ++++++++++++
> fs/smb/client/cifsglob.h | 1 +
> 3 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
> index 2d5e9a9d5b8b..e48a902efd52 100644
> --- a/fs/smb/client/cached_dir.c
> +++ b/fs/smb/client/cached_dir.c
> @@ -582,7 +582,7 @@ cifs_cfids_laundromat_thread(void *p)
> return 0;
> spin_lock(&cfids->cfid_list_lock);
> list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
> - if (time_after(jiffies, cfid->time + HZ * 30)) {
> + if (time_after(jiffies, cfid->time + HZ * max_dir_cache)) {
> list_del(&cfid->entry);
> list_add(&cfid->entry, &entry);
> cfids->num_entries--;
> diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
> index d49fd2bf71b0..7a89718d2a59 100644
> --- a/fs/smb/client/cifsfs.c
> +++ b/fs/smb/client/cifsfs.c
> @@ -117,6 +117,10 @@ module_param(cifs_max_pending, uint, 0444);
> MODULE_PARM_DESC(cifs_max_pending, "Simultaneous requests to server for "
> "CIFS/SMB1 dialect (N/A for SMB3) "
> "Default: 32767 Range: 2 to 32767.");
> +unsigned int max_dir_cache = 60;
> +module_param(max_dir_cache, uint, 0644);
> +MODULE_PARM_DESC(max_dir_cache, "Number of seconds to cache directory
> contents for which we have a lease. Default: 60 "
> + "Range: 1 to 65000 seconds");
> #ifdef CONFIG_CIFS_STATS2
> unsigned int slow_rsp_threshold = 1;
> module_param(slow_rsp_threshold, uint, 0644);
> @@ -1679,6 +1683,14 @@ init_cifs(void)
> CIFS_MAX_REQ);
> }
>
> + if (max_dir_cache < 1) {
> + max_dir_cache = 1;
> + cifs_dbg(VFS, "max_dir_cache timeout set to min of 1 second\n");
> + } else if (max_dir_cache > 65000) {
> + max_dir_cache = 65000;
> + cifs_dbg(VFS, "max_dir_cache timeout set to max of 65000 seconds\n");
> + }
> +
> cifsiod_wq = alloc_workqueue("cifsiod", WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
> if (!cifsiod_wq) {
> rc = -ENOMEM;
> diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
> index 259e231f8b4f..7aeeaa260cce 100644
> --- a/fs/smb/client/cifsglob.h
> +++ b/fs/smb/client/cifsglob.h
> @@ -2016,6 +2016,7 @@ extern unsigned int CIFSMaxBufSize; /* max size
> not including hdr */
> extern unsigned int cifs_min_rcv; /* min size of big ntwrk buf pool */
> extern unsigned int cifs_min_small; /* min size of small buf pool */
> extern unsigned int cifs_max_pending; /* MAX requests at once to server*/
> +extern unsigned int max_dir_cache; /* max time for directory lease
> caching of dir */
> extern bool disable_legacy_dialects; /* forbid vers=1.0 and vers=2.0 mounts */
> extern atomic_t mid_count;
>
>
> --
> Thanks,
>
> Steve
--
Thanks,
Steve
From c5e18f4d5e2a14ceb51314067984d488829e45ca Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Wed, 30 Aug 2023 22:48:41 -0500
Subject: [PATCH] smb3: allow controlling length of time directory entries are
cached with dir leases
Currently with directory leases we cache directory contents for a fixed period
of time (default 30 seconds) but for many workloads this is too short. Allow
configuring the maximum amount of time directory entries are cached when a
directory lease is held on that directory. Add module load parm "max_dir_cache"
For example to set the timeout to 10 minutes you would do:
echo 600 > /sys/module/cifs/parameters/dir_cache_timeout
or to disable caching directory contents:
echo 0 > /sys/module/cifs/parameters/dir_cache_timeout
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/smb/client/cached_dir.c | 4 ++--
fs/smb/client/cifsfs.c | 10 ++++++++++
fs/smb/client/cifsglob.h | 1 +
3 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index 2d5e9a9d5b8b..9d84c4a7bd0c 100644
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -145,7 +145,7 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
const char *npath;
if (tcon == NULL || tcon->cfids == NULL || tcon->nohandlecache ||
- is_smb1_server(tcon->ses->server))
+ is_smb1_server(tcon->ses->server) || (dir_cache_timeout == 0))
return -EOPNOTSUPP;
ses = tcon->ses;
@@ -582,7 +582,7 @@ cifs_cfids_laundromat_thread(void *p)
return 0;
spin_lock(&cfids->cfid_list_lock);
list_for_each_entry_safe(cfid, q, &cfids->entries, entry) {
- if (time_after(jiffies, cfid->time + HZ * 30)) {
+ if (time_after(jiffies, cfid->time + HZ * dir_cache_timeout)) {
list_del(&cfid->entry);
list_add(&cfid->entry, &entry);
cfids->num_entries--;
diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index d49fd2bf71b0..b92e9a138443 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -117,6 +117,10 @@ module_param(cifs_max_pending, uint, 0444);
MODULE_PARM_DESC(cifs_max_pending, "Simultaneous requests to server for "
"CIFS/SMB1 dialect (N/A for SMB3) "
"Default: 32767 Range: 2 to 32767.");
+unsigned int dir_cache_timeout = 60;
+module_param(dir_cache_timeout, uint, 0644);
+MODULE_PARM_DESC(dir_cache_timeout, "Number of seconds to cache directory contents for which we have a lease. Default: 60 "
+ "Range: 1 to 65000 seconds, 0 to disable caching dir contents");
#ifdef CONFIG_CIFS_STATS2
unsigned int slow_rsp_threshold = 1;
module_param(slow_rsp_threshold, uint, 0644);
@@ -1679,6 +1683,12 @@ init_cifs(void)
CIFS_MAX_REQ);
}
+ /* Limit max to about 18 hours, and setting to zero disables directory entry caching */
+ if (dir_cache_timeout > 65000) {
+ dir_cache_timeout = 65000;
+ cifs_dbg(VFS, "dir_cache_timeout set to max of 65000 seconds\n");
+ }
+
cifsiod_wq = alloc_workqueue("cifsiod", WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
if (!cifsiod_wq) {
rc = -ENOMEM;
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 259e231f8b4f..501426ee39e7 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -2016,6 +2016,7 @@ extern unsigned int CIFSMaxBufSize; /* max size not including hdr */
extern unsigned int cifs_min_rcv; /* min size of big ntwrk buf pool */
extern unsigned int cifs_min_small; /* min size of small buf pool */
extern unsigned int cifs_max_pending; /* MAX requests at once to server*/
+extern unsigned int dir_cache_timeout; /* max time for directory lease caching of dir */
extern bool disable_legacy_dialects; /* forbid vers=1.0 and vers=2.0 mounts */
extern atomic_t mid_count;
--
2.34.1
