Currently btrfs compression code use custom wrapper
for store allocated compression/heuristic workspaces.
That logic try store at least ncpu+1 each type of workspaces.
As far, as i can see that logic fully reimplement
mempool API.
So i think, that use of mempool api can simplify code
and allow for cleanup it.
That a proof of concept patch, i have tested it (at least that works),
future version will looks mostly same.
If that acceptable,
next step will be:
1. Create mempool_alloc_w()
that will resize mempool to apropriate size ncpu+1
And will create apropriate mempool, if creating failed in __init.
2. Convert per compression ws to mempool.
Thanks.
Signed-off-by: Timofey Titovets <nefelim...@gmail.com>
Cc: David Sterba <dste...@suse.com>
---
fs/btrfs/compression.c | 123 ++++++++++++++++---------------------------------
1 file changed, 39 insertions(+), 84 deletions(-)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 208334aa6c6e..cf47089b9ec0 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -34,6 +34,7 @@
#include <linux/slab.h>
#include <linux/sched/mm.h>
#include <linux/log2.h>
+#include <linux/mempool.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
@@ -768,14 +769,11 @@ struct heuristic_ws {
struct bucket_item *bucket;
/* Sorting buffer */
struct bucket_item *bucket_b;
- struct list_head list;
};
-static void free_heuristic_ws(struct list_head *ws)
+static void heuristic_ws_free(void *element, void *pool_data)
{
- struct heuristic_ws *workspace;
-
- workspace = list_entry(ws, struct heuristic_ws, list);
+ struct heuristic_ws *workspace = (struct heuristic_ws *) element;
kvfree(workspace->sample);
kfree(workspace->bucket);
@@ -783,13 +781,12 @@ static void free_heuristic_ws(struct list_head *ws)
kfree(workspace);
}
-static struct list_head *alloc_heuristic_ws(void)
+static void *heuristic_ws_alloc(gfp_t gfp_mask, void *pool_data)
{
- struct heuristic_ws *ws;
+ struct heuristic_ws *ws = kmalloc(sizeof(*ws), GFP_KERNEL);
- ws = kzalloc(sizeof(*ws), GFP_KERNEL);
if (!ws)
- return ERR_PTR(-ENOMEM);
+ return ws;
ws->sample = kvmalloc(MAX_SAMPLE_SIZE, GFP_KERNEL);
if (!ws->sample)
@@ -803,11 +800,14 @@ static struct list_head *alloc_heuristic_ws(void)
if (!ws->bucket_b)
goto fail;
- INIT_LIST_HEAD(&ws->list);
- return &ws->list;
+ return ws;
+
fail:
- free_heuristic_ws(&ws->list);
- return ERR_PTR(-ENOMEM);
+ kvfree(ws->sample);
+ kfree(ws->bucket);
+ kfree(ws->bucket_b);
+ kfree(ws);
+ return NULL;
}
struct workspaces_list {
@@ -821,10 +821,9 @@ struct workspaces_list {
wait_queue_head_t ws_wait;
};
+static mempool_t *btrfs_heuristic_ws_pool;
static struct workspaces_list btrfs_comp_ws[BTRFS_COMPRESS_TYPES];
-static struct workspaces_list btrfs_heuristic_ws;
-
static const struct btrfs_compress_op * const btrfs_compress_op[] = {
&btrfs_zlib_compress,
&btrfs_lzo_compress,
@@ -836,20 +835,15 @@ void __init btrfs_init_compress(void)
struct list_head *workspace;
int i;
- INIT_LIST_HEAD(&btrfs_heuristic_ws.idle_ws);
- spin_lock_init(&btrfs_heuristic_ws.ws_lock);
- atomic_set(&btrfs_heuristic_ws.total_ws, 0);
- init_waitqueue_head(&btrfs_heuristic_ws.ws_wait);
+ /*
+ * Try preallocate pool with minimum size for successful
+ * initialization of btrfs module
+ */
+ btrfs_heuristic_ws_pool = mempool_create(1, heuristic_ws_alloc,
+ heuristic_ws_free, NULL);
- workspace = alloc_heuristic_ws();
- if (IS_ERR(workspace)) {
- pr_warn(
- "BTRFS: cannot preallocate heuristic workspace, will try later\n");
- } else {
- atomic_set(&btrfs_heuristic_ws.total_ws, 1);
- btrfs_heuristic_ws.free_ws = 1;
- list_add(workspace, &btrfs_heuristic_ws.idle_ws);
- }
+ if (IS_ERR(btrfs_heuristic_ws_pool))
+ pr_warn("BTRFS: cannot preallocate heuristic workspace, will
try later\n");
for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
INIT_LIST_HEAD(&btrfs_comp_ws[i].idle_ws);
@@ -878,7 +872,7 @@ void __init btrfs_init_compress(void)
* Preallocation makes a forward progress guarantees and we do not return
* errors.
*/
-static struct list_head *__find_workspace(int type, bool heuristic)
+static struct list_head *find_workspace(int type)
{
struct list_head *workspace;
int cpus = num_online_cpus();
@@ -890,19 +884,11 @@ static struct list_head *__find_workspace(int type, bool
heuristic)
wait_queue_head_t *ws_wait;
int *free_ws;
- if (heuristic) {
- idle_ws = &btrfs_heuristic_ws.idle_ws;
- ws_lock = &btrfs_heuristic_ws.ws_lock;
- total_ws = &btrfs_heuristic_ws.total_ws;
- ws_wait = &btrfs_heuristic_ws.ws_wait;
- free_ws = &btrfs_heuristic_ws.free_ws;
- } else {
- idle_ws = &btrfs_comp_ws[idx].idle_ws;
- ws_lock = &btrfs_comp_ws[idx].ws_lock;
- total_ws = &btrfs_comp_ws[idx].total_ws;
- ws_wait = &btrfs_comp_ws[idx].ws_wait;
- free_ws = &btrfs_comp_ws[idx].free_ws;
- }
+ idle_ws = &btrfs_comp_ws[idx].idle_ws;
+ ws_lock = &btrfs_comp_ws[idx].ws_lock;
+ total_ws = &btrfs_comp_ws[idx].total_ws;
+ ws_wait = &btrfs_comp_ws[idx].ws_wait;
+ free_ws = &btrfs_comp_ws[idx].free_ws;
again:
spin_lock(ws_lock);
@@ -933,10 +919,7 @@ static struct list_head *__find_workspace(int type, bool
heuristic)
* context of btrfs_compress_bio/btrfs_compress_pages
*/
nofs_flag = memalloc_nofs_save();
- if (heuristic)
- workspace = alloc_heuristic_ws();
- else
- workspace = btrfs_compress_op[idx]->alloc_workspace();
+ workspace = btrfs_compress_op[idx]->alloc_workspace();
memalloc_nofs_restore(nofs_flag);
if (IS_ERR(workspace)) {
@@ -967,17 +950,11 @@ static struct list_head *__find_workspace(int type, bool
heuristic)
return workspace;
}
-static struct list_head *find_workspace(int type)
-{
- return __find_workspace(type, false);
-}
-
/*
* put a workspace struct back on the list or free it if we have enough
* idle ones sitting around
*/
-static void __free_workspace(int type, struct list_head *workspace,
- bool heuristic)
+static void free_workspace(int type, struct list_head *workspace)
{
int idx = type - 1;
struct list_head *idle_ws;
@@ -986,19 +963,11 @@ static void __free_workspace(int type, struct list_head
*workspace,
wait_queue_head_t *ws_wait;
int *free_ws;
- if (heuristic) {
- idle_ws = &btrfs_heuristic_ws.idle_ws;
- ws_lock = &btrfs_heuristic_ws.ws_lock;
- total_ws = &btrfs_heuristic_ws.total_ws;
- ws_wait = &btrfs_heuristic_ws.ws_wait;
- free_ws = &btrfs_heuristic_ws.free_ws;
- } else {
- idle_ws = &btrfs_comp_ws[idx].idle_ws;
- ws_lock = &btrfs_comp_ws[idx].ws_lock;
- total_ws = &btrfs_comp_ws[idx].total_ws;
- ws_wait = &btrfs_comp_ws[idx].ws_wait;
- free_ws = &btrfs_comp_ws[idx].free_ws;
- }
+ idle_ws = &btrfs_comp_ws[idx].idle_ws;
+ ws_lock = &btrfs_comp_ws[idx].ws_lock;
+ total_ws = &btrfs_comp_ws[idx].total_ws;
+ ws_wait = &btrfs_comp_ws[idx].ws_wait;
+ free_ws = &btrfs_comp_ws[idx].free_ws;
spin_lock(ws_lock);
if (*free_ws <= num_online_cpus()) {
@@ -1009,10 +978,7 @@ static void __free_workspace(int type, struct list_head
*workspace,
}
spin_unlock(ws_lock);
- if (heuristic)
- free_heuristic_ws(workspace);
- else
- btrfs_compress_op[idx]->free_workspace(workspace);
+ btrfs_compress_op[idx]->free_workspace(workspace);
atomic_dec(total_ws);
wake:
/*
@@ -1023,11 +989,6 @@ static void __free_workspace(int type, struct list_head
*workspace,
wake_up(ws_wait);
}
-static void free_workspace(int type, struct list_head *ws)
-{
- return __free_workspace(type, ws, false);
-}
-
/*
* cleanup function for module exit
*/
@@ -1036,12 +997,7 @@ static void free_workspaces(void)
struct list_head *workspace;
int i;
- while (!list_empty(&btrfs_heuristic_ws.idle_ws)) {
- workspace = btrfs_heuristic_ws.idle_ws.next;
- list_del(workspace);
- free_heuristic_ws(workspace);
- atomic_dec(&btrfs_heuristic_ws.total_ws);
- }
+ mempool_destroy(btrfs_heuristic_ws_pool);
for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
while (!list_empty(&btrfs_comp_ws[i].idle_ws)) {
@@ -1558,13 +1514,12 @@ static void heuristic_collect_sample(struct inode
*inode, u64 start, u64 end,
*/
int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end)
{
- struct list_head *ws_list = __find_workspace(0, true);
struct heuristic_ws *ws;
u32 i;
u8 byte;
int ret = 0;
- ws = list_entry(ws_list, struct heuristic_ws, list);
+ ws = mempool_alloc(btrfs_heuristic_ws_pool, GFP_KERNEL);
heuristic_collect_sample(inode, start, end, ws);
@@ -1627,7 +1582,7 @@ int btrfs_compress_heuristic(struct inode *inode, u64
start, u64 end)
}
out:
- __free_workspace(0, ws_list, true);
+ mempool_free(ws, btrfs_heuristic_ws_pool);
return ret;
}
--
2.15.1
--
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