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Date: Sun, 17 Jul 2022 11:22:44 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>, Daeho Jeong <daeho43@...il.com>
Cc: Daeho Jeong <daehojeong@...gle.com>, kernel-team@...roid.com,
linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH 2/2] f2fs: handle decompress only post
processing in softirq
On 2022/6/22 0:07, Jaegeuk Kim wrote:
> 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))))
How about using allow_decompress_in_softirq() to wrap !f2fs_low_mem_mode()
to improve readability?
> + 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;
return -ENOMEM instead of magic number.
>
> 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;
Ditto,
> }
>
> + dic->rbuf = f2fs_vmap(dic->tpages, dic->cluster_size);
> + if (!dic->rbuf)
> + return 1;
Ditto,
> +
> + dic->cbuf = f2fs_vmap(dic->cpages, dic->nr_cpages);
> + if (!dic->cbuf)
> + return 1;
Ditto,
> +
> + cops = f2fs_cops[F2FS_I(dic->inode)->i_compress_algorithm];
No need to assign cops again?
> 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;
How about returning ret here instead of magic number?
> }
>
> - 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();
Is there any condition that in_task() is true here? Maybe I'm missing
something here....
Thanks,
>
> 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);
> }
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