Re: [f2fs-dev] [PATCH 2/2] f2fs: handle decompress only post processing in softirq

From: Jaegeuk Kim
Date: Tue Jun 21 2022 - 12:08:05 EST

Can we do like this which has no functional change but refactored
some functions?

---
fs/f2fs/compress.c | 208 ++++++++++++++++++++++++++++-----------------
fs/f2fs/data.c | 52 ++++++++----
fs/f2fs/f2fs.h | 17 ++--
3 files changed, 172 insertions(+), 105 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index fa237e5c7173..494ce3634b62 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -729,28 +729,18 @@ static int f2fs_compress_pages(struct compress_ctx *cc)
return ret;
}

-void f2fs_decompress_cluster(struct decompress_io_ctx *dic)
+static int f2fs_prepare_decomp_mem(struct decompress_io_ctx *dic, bool end_io)
{
- struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode);
- struct f2fs_inode_info *fi = F2FS_I(dic->inode);
const struct f2fs_compress_ops *cops =
- f2fs_cops[fi->i_compress_algorithm];
- int ret;
+ f2fs_cops[F2FS_I(dic->inode)->i_compress_algorithm];
int i;

- trace_f2fs_decompress_pages_start(dic->inode, dic->cluster_idx,
- dic->cluster_size, fi->i_compress_algorithm);
-
- if (dic->failed) {
- ret = -EIO;
- goto out_end_io;
- }
+ if (!(end_io ^ f2fs_low_mem_mode(F2FS_I_SB(dic->inode))))
+ return 0;

dic->tpages = page_array_alloc(dic->inode, dic->cluster_size);
- if (!dic->tpages) {
- ret = -ENOMEM;
- goto out_end_io;
- }
+ if (!dic->tpages)
+ return 1;

for (i = 0; i < dic->cluster_size; i++) {
if (dic->rpages[i]) {
@@ -759,28 +749,100 @@ void f2fs_decompress_cluster(struct decompress_io_ctx *dic)
}

dic->tpages[i] = f2fs_compress_alloc_page();
- if (!dic->tpages[i]) {
- ret = -ENOMEM;
- goto out_end_io;
- }
+ if (!dic->tpages[i])
+ return 1;
}

+ dic->rbuf = f2fs_vmap(dic->tpages, dic->cluster_size);
+ if (!dic->rbuf)
+ return 1;
+
+ dic->cbuf = f2fs_vmap(dic->cpages, dic->nr_cpages);
+ if (!dic->cbuf)
+ return 1;
+
+ cops = f2fs_cops[F2FS_I(dic->inode)->i_compress_algorithm];
if (cops->init_decompress_ctx) {
- ret = cops->init_decompress_ctx(dic);
+ int ret = cops->init_decompress_ctx(dic);
+
if (ret)
- goto out_end_io;
+ return 1;
}

- dic->rbuf = f2fs_vmap(dic->tpages, dic->cluster_size);
- if (!dic->rbuf) {
- ret = -ENOMEM;
- goto out_destroy_decompress_ctx;
+ return 0;
+}
+
+static void f2fs_release_decomp_mem(struct decompress_io_ctx *dic,
+ bool bypass_destroy_callback, bool end_io)
+{
+ const struct f2fs_compress_ops *cops =
+ f2fs_cops[F2FS_I(dic->inode)->i_compress_algorithm];
+
+ if (end_io ^ f2fs_low_mem_mode(F2FS_I_SB(dic->inode)))
+ return;
+
+ if (!bypass_destroy_callback && cops->destroy_decompress_ctx)
+ cops->destroy_decompress_ctx(dic);
+
+ if (dic->cbuf)
+ vm_unmap_ram(dic->cbuf, dic->nr_cpages);
+
+ if (dic->rbuf)
+ vm_unmap_ram(dic->rbuf, dic->cluster_size);
+}
+
+static void f2fs_free_dic(struct decompress_io_ctx *dic,
+ bool bypass_destroy_callback)
+{
+ int i;
+
+ f2fs_release_decomp_mem(dic, bypass_destroy_callback, false);
+
+ if (dic->tpages) {
+ for (i = 0; i < dic->cluster_size; i++) {
+ if (dic->rpages[i])
+ continue;
+ if (!dic->tpages[i])
+ continue;
+ f2fs_compress_free_page(dic->tpages[i]);
+ }
+ page_array_free(dic->inode, dic->tpages, dic->cluster_size);
}

- dic->cbuf = f2fs_vmap(dic->cpages, dic->nr_cpages);
- if (!dic->cbuf) {
+ if (dic->cpages) {
+ for (i = 0; i < dic->nr_cpages; i++) {
+ if (!dic->cpages[i])
+ continue;
+ f2fs_compress_free_page(dic->cpages[i]);
+ }
+ page_array_free(dic->inode, dic->cpages, dic->nr_cpages);
+ }
+
+ page_array_free(dic->inode, dic->rpages, dic->nr_rpages);
+ kmem_cache_free(dic_entry_slab, dic);
+}
+
+void f2fs_decompress_cluster(struct decompress_io_ctx *dic, bool in_task)
+{
+ struct f2fs_sb_info *sbi = F2FS_I_SB(dic->inode);
+ struct f2fs_inode_info *fi = F2FS_I(dic->inode);
+ const struct f2fs_compress_ops *cops =
+ f2fs_cops[fi->i_compress_algorithm];
+ bool bypass_callback = false;
+ int ret;
+
+ trace_f2fs_decompress_pages_start(dic->inode, dic->cluster_idx,
+ dic->cluster_size, fi->i_compress_algorithm);
+
+ if (dic->failed) {
+ ret = -EIO;
+ goto out_end_io;
+ }
+
+ if (f2fs_prepare_decomp_mem(dic, true)) {
+ bypass_callback = true;
ret = -ENOMEM;
- goto out_vunmap_rbuf;
+ goto out_release;
}

dic->clen = le32_to_cpu(dic->cbuf->clen);
@@ -788,7 +850,7 @@ void f2fs_decompress_cluster(struct decompress_io_ctx *dic)

if (dic->clen > PAGE_SIZE * dic->nr_cpages - COMPRESS_HEADER_SIZE) {
ret = -EFSCORRUPTED;
- goto out_vunmap_cbuf;
+ goto out_release;
}

ret = cops->decompress_pages(dic);
@@ -809,17 +871,13 @@ void f2fs_decompress_cluster(struct decompress_io_ctx *dic)
}
}

-out_vunmap_cbuf:
- vm_unmap_ram(dic->cbuf, dic->nr_cpages);
-out_vunmap_rbuf:
- vm_unmap_ram(dic->rbuf, dic->cluster_size);
-out_destroy_decompress_ctx:
- if (cops->destroy_decompress_ctx)
- cops->destroy_decompress_ctx(dic);
+out_release:
+ f2fs_release_decomp_mem(dic, bypass_callback, true);
+
out_end_io:
trace_f2fs_decompress_pages_end(dic->inode, dic->cluster_idx,
dic->clen, ret);
- f2fs_decompress_end_io(dic, ret);
+ f2fs_decompress_end_io(dic, ret, in_task);
}

/*
@@ -829,7 +887,7 @@ void f2fs_decompress_cluster(struct decompress_io_ctx *dic)
* (or in the case of a failure, cleans up without actually decompressing).
*/
void f2fs_end_read_compressed_page(struct page *page, bool failed,
- block_t blkaddr)
+ block_t blkaddr, bool in_task)
{
struct decompress_io_ctx *dic =
(struct decompress_io_ctx *)page_private(page);
@@ -839,12 +897,12 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,

if (failed)
WRITE_ONCE(dic->failed, true);
- else if (blkaddr)
+ else if (blkaddr && in_task)
f2fs_cache_compressed_page(sbi, page,
dic->inode->i_ino, blkaddr);

if (atomic_dec_and_test(&dic->remaining_pages))
- f2fs_decompress_cluster(dic);
+ f2fs_decompress_cluster(dic, in_task);
}

static bool is_page_in_cluster(struct compress_ctx *cc, pgoff_t index)
@@ -1552,16 +1610,14 @@ int f2fs_write_multi_pages(struct compress_ctx *cc,
return err;
}

-static void f2fs_free_dic(struct decompress_io_ctx *dic);
-
struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
{
struct decompress_io_ctx *dic;
pgoff_t start_idx = start_idx_of_cluster(cc);
+ struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
int i;

- dic = f2fs_kmem_cache_alloc(dic_entry_slab, GFP_F2FS_ZERO,
- false, F2FS_I_SB(cc->inode));
+ dic = f2fs_kmem_cache_alloc(dic_entry_slab, GFP_F2FS_ZERO, false, sbi);
if (!dic)
return ERR_PTR(-ENOMEM);

@@ -1602,52 +1658,43 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
dic->cpages[i] = page;
}

+ if (f2fs_prepare_decomp_mem(dic, false))
+ goto out_free;
+
return dic;

out_free:
- f2fs_free_dic(dic);
+ f2fs_free_dic(dic, true);
return ERR_PTR(-ENOMEM);
}

-static void f2fs_free_dic(struct decompress_io_ctx *dic)
+static void f2fs_late_free_dic(struct work_struct *work)
{
- int i;
-
- if (dic->tpages) {
- for (i = 0; i < dic->cluster_size; i++) {
- if (dic->rpages[i])
- continue;
- if (!dic->tpages[i])
- continue;
- f2fs_compress_free_page(dic->tpages[i]);
- }
- page_array_free(dic->inode, dic->tpages, dic->cluster_size);
- }
-
- if (dic->cpages) {
- for (i = 0; i < dic->nr_cpages; i++) {
- if (!dic->cpages[i])
- continue;
- f2fs_compress_free_page(dic->cpages[i]);
- }
- page_array_free(dic->inode, dic->cpages, dic->nr_cpages);
- }
+ struct decompress_io_ctx *dic =
+ container_of(work, struct decompress_io_ctx, free_work);

- page_array_free(dic->inode, dic->rpages, dic->nr_rpages);
- kmem_cache_free(dic_entry_slab, dic);
+ f2fs_free_dic(dic, false);
}

-static void f2fs_put_dic(struct decompress_io_ctx *dic)
+static void f2fs_put_dic(struct decompress_io_ctx *dic, bool in_task)
{
- if (refcount_dec_and_test(&dic->refcnt))
- f2fs_free_dic(dic);
+ if (refcount_dec_and_test(&dic->refcnt)) {
+ if (in_task) {
+ f2fs_free_dic(dic, false);
+ } else {
+ INIT_WORK(&dic->free_work, f2fs_late_free_dic);
+ queue_work(F2FS_I_SB(dic->inode)->post_read_wq,
+ &dic->free_work);
+ }
+ }
}

/*
* Update and unlock the cluster's pagecache pages, and release the reference to
* the decompress_io_ctx that was being held for I/O completion.
*/
-static void __f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed)
+static void __f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
+ bool in_task)
{
int i;

@@ -1668,7 +1715,7 @@ static void __f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed)
unlock_page(rpage);
}

- f2fs_put_dic(dic);
+ f2fs_put_dic(dic, in_task);
}

static void f2fs_verify_cluster(struct work_struct *work)
@@ -1685,14 +1732,15 @@ static void f2fs_verify_cluster(struct work_struct *work)
SetPageError(rpage);
}

- __f2fs_decompress_end_io(dic, false);
+ __f2fs_decompress_end_io(dic, false, true);
}

/*
* This is called when a compressed cluster has been decompressed
* (or failed to be read and/or decompressed).
*/
-void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed)
+void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
+ bool in_task)
{
if (!failed && dic->need_verity) {
/*
@@ -1704,7 +1752,7 @@ void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed)
INIT_WORK(&dic->verity_work, f2fs_verify_cluster);
fsverity_enqueue_verify_work(&dic->verity_work);
} else {
- __f2fs_decompress_end_io(dic, failed);
+ __f2fs_decompress_end_io(dic, failed, in_task);
}
}

@@ -1713,12 +1761,12 @@ void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed)
*
* This is called when the page is no longer needed and can be freed.
*/
-void f2fs_put_page_dic(struct page *page)
+void f2fs_put_page_dic(struct page *page, bool in_task)
{
struct decompress_io_ctx *dic =
(struct decompress_io_ctx *)page_private(page);

- f2fs_put_dic(dic);
+ f2fs_put_dic(dic, in_task);
}

/*
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 7fcbcf979737..c448c3ee7ac3 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -119,7 +119,7 @@ struct bio_post_read_ctx {
block_t fs_blkaddr;
};

-static void f2fs_finish_read_bio(struct bio *bio)
+static void f2fs_finish_read_bio(struct bio *bio, bool in_task)
{
struct bio_vec *bv;
struct bvec_iter_all iter_all;
@@ -133,8 +133,9 @@ static void f2fs_finish_read_bio(struct bio *bio)

if (f2fs_is_compressed_page(page)) {
if (bio->bi_status)
- f2fs_end_read_compressed_page(page, true, 0);
- f2fs_put_page_dic(page);
+ f2fs_end_read_compressed_page(page, true, 0,
+ in_task);
+ f2fs_put_page_dic(page, in_task);
continue;
}

@@ -191,7 +192,7 @@ static void f2fs_verify_bio(struct work_struct *work)
fsverity_verify_bio(bio);
}

- f2fs_finish_read_bio(bio);
+ f2fs_finish_read_bio(bio, true);
}

/*
@@ -203,7 +204,7 @@ static void f2fs_verify_bio(struct work_struct *work)
* can involve reading verity metadata pages from the file, and these verity
* metadata pages may be encrypted and/or compressed.
*/
-static void f2fs_verify_and_finish_bio(struct bio *bio)
+static void f2fs_verify_and_finish_bio(struct bio *bio, bool in_task)
{
struct bio_post_read_ctx *ctx = bio->bi_private;

@@ -211,7 +212,7 @@ static void f2fs_verify_and_finish_bio(struct bio *bio)
INIT_WORK(&ctx->work, f2fs_verify_bio);
fsverity_enqueue_verify_work(&ctx->work);
} else {
- f2fs_finish_read_bio(bio);
+ f2fs_finish_read_bio(bio, in_task);
}
}

@@ -224,7 +225,8 @@ static void f2fs_verify_and_finish_bio(struct bio *bio)
* that the bio includes at least one compressed page. The actual decompression
* is done on a per-cluster basis, not a per-bio basis.
*/
-static void f2fs_handle_step_decompress(struct bio_post_read_ctx *ctx)
+static void f2fs_handle_step_decompress(struct bio_post_read_ctx *ctx,
+ bool in_task)
{
struct bio_vec *bv;
struct bvec_iter_all iter_all;
@@ -237,7 +239,7 @@ static void f2fs_handle_step_decompress(struct bio_post_read_ctx *ctx)
/* PG_error was set if decryption failed. */
if (f2fs_is_compressed_page(page))
f2fs_end_read_compressed_page(page, PageError(page),
- blkaddr);
+ blkaddr, in_task);
else
all_compressed = false;

@@ -262,15 +264,16 @@ static void f2fs_post_read_work(struct work_struct *work)
fscrypt_decrypt_bio(ctx->bio);

if (ctx->enabled_steps & STEP_DECOMPRESS)
- f2fs_handle_step_decompress(ctx);
+ f2fs_handle_step_decompress(ctx, true);

- f2fs_verify_and_finish_bio(ctx->bio);
+ f2fs_verify_and_finish_bio(ctx->bio, true);
}

static void f2fs_read_end_io(struct bio *bio)
{
struct f2fs_sb_info *sbi = F2FS_P_SB(bio_first_page_all(bio));
struct bio_post_read_ctx *ctx;
+ bool intask = in_task();

iostat_update_and_unbind_ctx(bio, 0);
ctx = bio->bi_private;
@@ -281,16 +284,29 @@ static void f2fs_read_end_io(struct bio *bio)
}

if (bio->bi_status) {
- f2fs_finish_read_bio(bio);
+ f2fs_finish_read_bio(bio, intask);
return;
}

- if (ctx && (ctx->enabled_steps & (STEP_DECRYPT | STEP_DECOMPRESS))) {
- INIT_WORK(&ctx->work, f2fs_post_read_work);
- queue_work(ctx->sbi->post_read_wq, &ctx->work);
- } else {
- f2fs_verify_and_finish_bio(bio);
+ if (ctx) {
+ unsigned int enabled_steps = ctx->enabled_steps &
+ (STEP_DECRYPT | STEP_DECOMPRESS);
+
+ /*
+ * If we have only decompression step between decompression and
+ * decrypt, we don't need post processing for this.
+ */
+ if (enabled_steps == STEP_DECOMPRESS &&
+ !f2fs_low_mem_mode(sbi)) {
+ f2fs_handle_step_decompress(ctx, intask);
+ } else if (enabled_steps) {
+ INIT_WORK(&ctx->work, f2fs_post_read_work);
+ queue_work(ctx->sbi->post_read_wq, &ctx->work);
+ return;
+ }
}
+
+ f2fs_verify_and_finish_bio(bio, intask);
}

static void f2fs_write_end_io(struct bio *bio)
@@ -2222,7 +2238,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,

if (f2fs_load_compressed_page(sbi, page, blkaddr)) {
if (atomic_dec_and_test(&dic->remaining_pages))
- f2fs_decompress_cluster(dic);
+ f2fs_decompress_cluster(dic, true);
continue;
}

@@ -2240,7 +2256,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
page->index, for_write);
if (IS_ERR(bio)) {
ret = PTR_ERR(bio);
- f2fs_decompress_end_io(dic, ret);
+ f2fs_decompress_end_io(dic, ret, true);
f2fs_put_dnode(&dn);
*bio_ret = NULL;
return ret;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index fea97093d927..c9a31934b948 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1588,6 +1588,7 @@ struct decompress_io_ctx {
void *private; /* payload buffer for specified decompression algorithm */
void *private2; /* extra payload buffer */
struct work_struct verity_work; /* work to verify the decompressed pages */
+ struct work_struct free_work; /* work for late free this structure itself */
};

#define NULL_CLUSTER ((unsigned int)(~0))
@@ -4166,9 +4167,9 @@ void f2fs_compress_write_end_io(struct bio *bio, struct page *page);
bool f2fs_is_compress_backend_ready(struct inode *inode);
int f2fs_init_compress_mempool(void);
void f2fs_destroy_compress_mempool(void);
-void f2fs_decompress_cluster(struct decompress_io_ctx *dic);
+void f2fs_decompress_cluster(struct decompress_io_ctx *dic, bool in_task);
void f2fs_end_read_compressed_page(struct page *page, bool failed,
- block_t blkaddr);
+ block_t blkaddr, bool in_task);
bool f2fs_cluster_is_empty(struct compress_ctx *cc);
bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
bool f2fs_all_cluster_page_loaded(struct compress_ctx *cc, struct pagevec *pvec,
@@ -4187,8 +4188,9 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
unsigned nr_pages, sector_t *last_block_in_bio,
bool is_readahead, bool for_write);
struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc);
-void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed);
-void f2fs_put_page_dic(struct page *page);
+void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
+ bool in_task);
+void f2fs_put_page_dic(struct page *page, bool in_task);
unsigned int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn);
int f2fs_init_compress_ctx(struct compress_ctx *cc);
void f2fs_destroy_compress_ctx(struct compress_ctx *cc, bool reuse);
@@ -4234,13 +4236,14 @@ static inline struct page *f2fs_compress_control_page(struct page *page)
}
static inline int f2fs_init_compress_mempool(void) { return 0; }
static inline void f2fs_destroy_compress_mempool(void) { }
-static inline void f2fs_decompress_cluster(struct decompress_io_ctx *dic) { }
+static inline void f2fs_decompress_cluster(struct decompress_io_ctx *dic,
+ bool in_task) { }
static inline void f2fs_end_read_compressed_page(struct page *page,
- bool failed, block_t blkaddr)
+ bool failed, block_t blkaddr, bool in_task)
{
WARN_ON_ONCE(1);
}
-static inline void f2fs_put_page_dic(struct page *page)
+static inline void f2fs_put_page_dic(struct page *page, bool in_task)
{
WARN_ON_ONCE(1);
}
--
2.37.0.rc0.104.g0611611a94-goog