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authorPavel Begunkov <asml.silence@gmail.com>2021-08-09 13:04:01 +0100
committerJens Axboe <axboe@kernel.dk>2021-08-09 09:05:44 -0600
commit911cd0d3e16d37882df2fa223ec906e7e616f60a (patch)
tree186f2f0244e1619654d2cb10b708deb16ce4e2fd
parentb26d1744f1efd78d137e732bbe4eef4ebb098071 (diff)
io_uring: use kvmalloc for fixed files
Instead of hand-coded two-level tables for registered files, allocate them with kvmalloc(). In many cases small enough tables are enough, and so can be kmalloc()'ed removing an extra memory load and a bunch of bit logic instructions from the hot path. If the table is larger, we trade off all the pros with a TLB-assisted memory lookup. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/280421d3b48775dabab773006bb5588c7b2dabc0.1628471125.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/io_uring.c33
1 files changed, 10 insertions, 23 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index c9e415671dc0..8f566428afe4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -92,13 +92,8 @@
#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
#define IORING_SQPOLL_CAP_ENTRIES_VALUE 8
-/*
- * Shift of 9 is 512 entries, or exactly one page on 64-bit archs
- */
-#define IORING_FILE_TABLE_SHIFT 9
-#define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT)
-#define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1)
-#define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE)
+/* 512 entries per page on 64-bit archs, 64 pages max */
+#define IORING_MAX_FIXED_FILES (1U << 15)
#define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \
IORING_REGISTER_LAST + IORING_OP_LAST)
@@ -235,8 +230,7 @@ struct io_rsrc_put {
};
struct io_file_table {
- /* two level table */
- struct io_fixed_file **files;
+ struct io_fixed_file *files;
};
struct io_rsrc_node {
@@ -6334,12 +6328,9 @@ static void io_wq_submit_work(struct io_wq_work *work)
#define FFS_MASK ~(FFS_ASYNC_READ|FFS_ASYNC_WRITE|FFS_ISREG)
static inline struct io_fixed_file *io_fixed_file_slot(struct io_file_table *table,
- unsigned i)
+ unsigned i)
{
- struct io_fixed_file *table_l2;
-
- table_l2 = table->files[i >> IORING_FILE_TABLE_SHIFT];
- return &table_l2[i & IORING_FILE_TABLE_MASK];
+ return &table->files[i];
}
static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
@@ -7279,17 +7270,13 @@ fail:
static bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files)
{
- size_t size = nr_files * sizeof(struct io_fixed_file);
-
- table->files = (struct io_fixed_file **)io_alloc_page_table(size);
+ table->files = kvcalloc(nr_files, sizeof(table->files[0]), GFP_KERNEL);
return !!table->files;
}
-static void io_free_file_tables(struct io_file_table *table, unsigned nr_files)
+static void io_free_file_tables(struct io_file_table *table)
{
- size_t size = nr_files * sizeof(struct io_fixed_file);
-
- io_free_page_table((void **)table->files, size);
+ kvfree(table->files);
table->files = NULL;
}
@@ -7314,7 +7301,7 @@ static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
fput(file);
}
#endif
- io_free_file_tables(&ctx->file_table, ctx->nr_user_files);
+ io_free_file_tables(&ctx->file_table);
io_rsrc_data_free(ctx->file_data);
ctx->file_data = NULL;
ctx->nr_user_files = 0;
@@ -7782,7 +7769,7 @@ out_fput:
if (file)
fput(file);
}
- io_free_file_tables(&ctx->file_table, nr_args);
+ io_free_file_tables(&ctx->file_table);
ctx->nr_user_files = 0;
out_free:
io_rsrc_data_free(ctx->file_data);