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platform_kernel-5.15
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io_uring: file registration list and lock optimization 

There's no point in using list_del_init() on entries that are going
away, and the associated lock is always used in process context so
let's not use the IRQ disabling+saving variant of the spinlock.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2020-05-15 14:30:38 -06:00
parent 7e55a19cf6
commit 6a4d07cde5
1 changed files with 10 additions and 14 deletions
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24
fs/io_uring.c
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@ -6264,16 +6264,15 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
struct fixed_file_data *data = ctx->file_data; struct fixed_file_data *data = ctx->file_data;
struct fixed_file_ref_node *ref_node = NULL; struct fixed_file_ref_node *ref_node = NULL;
unsigned nr_tables, i; unsigned nr_tables, i;
unsigned long flags;
if (!data) if (!data)
return -ENXIO; return -ENXIO;
spin_lock_irqsave(&data->lock, flags); spin_lock(&data->lock);
if (!list_empty(&data->ref_list)) if (!list_empty(&data->ref_list))
ref_node = list_first_entry(&data->ref_list, ref_node = list_first_entry(&data->ref_list,
struct fixed_file_ref_node, node); struct fixed_file_ref_node, node);
spin_unlock_irqrestore(&data->lock, flags); spin_unlock(&data->lock);
if (ref_node) if (ref_node)
percpu_ref_kill(&ref_node->refs); percpu_ref_kill(&ref_node->refs);
@ -6516,17 +6515,16 @@ static void __io_file_put_work(struct fixed_file_ref_node *ref_node)
struct fixed_file_data *file_data = ref_node->file_data; struct fixed_file_data *file_data = ref_node->file_data;
struct io_ring_ctx *ctx = file_data->ctx; struct io_ring_ctx *ctx = file_data->ctx;
struct io_file_put *pfile, *tmp; struct io_file_put *pfile, *tmp;
unsigned long flags;
list_for_each_entry_safe(pfile, tmp, &ref_node->file_list, list) { list_for_each_entry_safe(pfile, tmp, &ref_node->file_list, list) {
list_del_init(&pfile->list); list_del(&pfile->list);
io_ring_file_put(ctx, pfile->file); io_ring_file_put(ctx, pfile->file);
kfree(pfile); kfree(pfile);
} }
spin_lock_irqsave(&file_data->lock, flags); spin_lock(&file_data->lock);
list_del_init(&ref_node->node); list_del(&ref_node->node);
spin_unlock_irqrestore(&file_data->lock, flags); spin_unlock(&file_data->lock);
percpu_ref_exit(&ref_node->refs); percpu_ref_exit(&ref_node->refs);
kfree(ref_node); kfree(ref_node);
@ -6606,7 +6604,6 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
int fd, ret = 0; int fd, ret = 0;
unsigned i; unsigned i;
struct fixed_file_ref_node *ref_node; struct fixed_file_ref_node *ref_node;
unsigned long flags;
if (ctx->file_data) if (ctx->file_data)
return -EBUSY; return -EBUSY;
@ -6714,9 +6711,9 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
} }
ctx->file_data->cur_refs = &ref_node->refs; ctx->file_data->cur_refs = &ref_node->refs;
spin_lock_irqsave(&ctx->file_data->lock, flags); spin_lock(&ctx->file_data->lock);
list_add(&ref_node->node, &ctx->file_data->ref_list); list_add(&ref_node->node, &ctx->file_data->ref_list);
spin_unlock_irqrestore(&ctx->file_data->lock, flags); spin_unlock(&ctx->file_data->lock);
percpu_ref_get(&ctx->file_data->refs); percpu_ref_get(&ctx->file_data->refs);
return ret; return ret;
} }
@ -6792,7 +6789,6 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
__s32 __user *fds; __s32 __user *fds;
int fd, i, err; int fd, i, err;
__u32 done; __u32 done;
unsigned long flags;
bool needs_switch = false; bool needs_switch = false;
if (check_add_overflow(up->offset, nr_args, &done)) if (check_add_overflow(up->offset, nr_args, &done))
@ -6857,10 +6853,10 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
if (needs_switch) { if (needs_switch) {
percpu_ref_kill(data->cur_refs); percpu_ref_kill(data->cur_refs);
spin_lock_irqsave(&data->lock, flags); spin_lock(&data->lock);
list_add(&ref_node->node, &data->ref_list); list_add(&ref_node->node, &data->ref_list);
data->cur_refs = &ref_node->refs; data->cur_refs = &ref_node->refs;
spin_unlock_irqrestore(&data->lock, flags); spin_unlock(&data->lock);
percpu_ref_get(&ctx->file_data->refs); percpu_ref_get(&ctx->file_data->refs);
} else } else
destroy_fixed_file_ref_node(ref_node); destroy_fixed_file_ref_node(ref_node);