Commit 02c048b9 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

fuse: allow batching of FORGET requests



Terje Malmedal reports that a fuse filesystem with 32 million inodes
on a machine with lots of memory can take up to 30 minutes to process
FORGET requests when all those inodes are evicted from the icache.

To solve this, create a BATCH_FORGET request that allows up to about
8000 FORGET requests to be sent in a single message.

This request is only sent if userspace supports interface version 7.16
or later, otherwise fall back to sending individual FORGET messages.
Reported-by: default avatarTerje Malmedal <terje.malmedal@usit.uio.no>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent 07e77dca
......@@ -254,8 +254,8 @@ static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
u64 nodeid, u64 nlookup)
{
forget->nodeid = nodeid;
forget->nlookup = nlookup;
forget->forget_one.nodeid = nodeid;
forget->forget_one.nlookup = nlookup;
spin_lock(&fc->lock);
fc->forget_list_tail->next = forget;
......@@ -974,15 +974,26 @@ __releases(fc->lock)
return err ? err : reqsize;
}
static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc)
static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
unsigned max,
unsigned *countp)
{
struct fuse_forget_link *forget = fc->forget_list_head.next;
struct fuse_forget_link *head = fc->forget_list_head.next;
struct fuse_forget_link **newhead = &head;
unsigned count;
fc->forget_list_head.next = forget->next;
for (count = 0; *newhead != NULL && count < max; count++)
newhead = &(*newhead)->next;
fc->forget_list_head.next = *newhead;
*newhead = NULL;
if (fc->forget_list_head.next == NULL)
fc->forget_list_tail = &fc->forget_list_head;
return forget;
if (countp != NULL)
*countp = count;
return head;
}
static int fuse_read_single_forget(struct fuse_conn *fc,
......@@ -991,13 +1002,13 @@ static int fuse_read_single_forget(struct fuse_conn *fc,
__releases(fc->lock)
{
int err;
struct fuse_forget_link *forget = dequeue_forget(fc);
struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
struct fuse_forget_in arg = {
.nlookup = forget->nlookup,
.nlookup = forget->forget_one.nlookup,
};
struct fuse_in_header ih = {
.opcode = FUSE_FORGET,
.nodeid = forget->nodeid,
.nodeid = forget->forget_one.nodeid,
.unique = fuse_get_unique(fc),
.len = sizeof(ih) + sizeof(arg),
};
......@@ -1018,6 +1029,65 @@ __releases(fc->lock)
return ih.len;
}
static int fuse_read_batch_forget(struct fuse_conn *fc,
struct fuse_copy_state *cs, size_t nbytes)
__releases(fc->lock)
{
int err;
unsigned max_forgets;
unsigned count;
struct fuse_forget_link *head;
struct fuse_batch_forget_in arg = { .count = 0 };
struct fuse_in_header ih = {
.opcode = FUSE_BATCH_FORGET,
.unique = fuse_get_unique(fc),
.len = sizeof(ih) + sizeof(arg),
};
if (nbytes < ih.len) {
spin_unlock(&fc->lock);
return -EINVAL;
}
max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
head = dequeue_forget(fc, max_forgets, &count);
spin_unlock(&fc->lock);
arg.count = count;
ih.len += count * sizeof(struct fuse_forget_one);
err = fuse_copy_one(cs, &ih, sizeof(ih));
if (!err)
err = fuse_copy_one(cs, &arg, sizeof(arg));
while (head) {
struct fuse_forget_link *forget = head;
if (!err) {
err = fuse_copy_one(cs, &forget->forget_one,
sizeof(forget->forget_one));
}
head = forget->next;
kfree(forget);
}
fuse_copy_finish(cs);
if (err)
return err;
return ih.len;
}
static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
size_t nbytes)
__releases(fc->lock)
{
if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
return fuse_read_single_forget(fc, cs, nbytes);
else
return fuse_read_batch_forget(fc, cs, nbytes);
}
/*
* Read a single request into the userspace filesystem's buffer. This
* function waits until a request is available, then removes it from
......@@ -1058,7 +1128,7 @@ static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
if (forget_pending(fc)) {
if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
return fuse_read_single_forget(fc, cs, nbytes);
return fuse_read_forget(fc, cs, nbytes);
if (fc->forget_batch <= -8)
fc->forget_batch = 16;
......@@ -1837,7 +1907,7 @@ __acquires(fc->lock)
end_requests(fc, &fc->pending);
end_requests(fc, &fc->processing);
while (forget_pending(fc))
kfree(dequeue_forget(fc));
kfree(dequeue_forget(fc, 1, NULL));
}
/*
......
......@@ -55,8 +55,7 @@ extern unsigned max_user_congthresh;
/* One forget request */
struct fuse_forget_link {
u64 nodeid;
u64 nlookup;
struct fuse_forget_one forget_one;
struct fuse_forget_link *next;
};
......
......@@ -41,6 +41,9 @@
* 7.15
* - add store notify
* - add retrieve notify
*
* 7.16
* - add BATCH_FORGET request
*/
#ifndef _LINUX_FUSE_H
......@@ -72,7 +75,7 @@
#define FUSE_KERNEL_VERSION 7
/** Minor version number of this interface */
#define FUSE_KERNEL_MINOR_VERSION 15
#define FUSE_KERNEL_MINOR_VERSION 16
/** The node ID of the root inode */
#define FUSE_ROOT_ID 1
......@@ -256,6 +259,7 @@ enum fuse_opcode {
FUSE_IOCTL = 39,
FUSE_POLL = 40,
FUSE_NOTIFY_REPLY = 41,
FUSE_BATCH_FORGET = 42,
/* CUSE specific operations */
CUSE_INIT = 4096,
......@@ -290,6 +294,16 @@ struct fuse_forget_in {
__u64 nlookup;
};
struct fuse_forget_one {
__u64 nodeid;
__u64 nlookup;
};
struct fuse_batch_forget_in {
__u32 count;
__u32 dummy;
};
struct fuse_getattr_in {
__u32 getattr_flags;
__u32 dummy;
......
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