f2fs: handle decompress only post processing in softirq

Now decompression is being handled in workqueue and it makes read I/O
latency non-deterministic, because of the non-deterministic scheduling
nature of workqueues. So, I made it handled in softirq context only if
possible, not in low memory devices, since this modification will
maintain decompresion related memory a little longer.

Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index fa237e5..086e6f7 100644 (file)
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -729,14 +729,19 @@ out:
        return ret;
 }
 
-void f2fs_decompress_cluster(struct decompress_io_ctx *dic)
+static int f2fs_prepare_decomp_mem(struct decompress_io_ctx *dic,
+               bool pre_alloc);
+static void f2fs_release_decomp_mem(struct decompress_io_ctx *dic,
+               bool bypass_destroy_callback, bool pre_alloc);
+
+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;
-       int i;
 
        trace_f2fs_decompress_pages_start(dic->inode, dic->cluster_idx,
                                dic->cluster_size, fi->i_compress_algorithm);
@@ -746,41 +751,10 @@ void f2fs_decompress_cluster(struct decompress_io_ctx *dic)
                goto out_end_io;
        }
 
-       dic->tpages = page_array_alloc(dic->inode, dic->cluster_size);
-       if (!dic->tpages) {
-               ret = -ENOMEM;
-               goto out_end_io;
-       }
-
-       for (i = 0; i < dic->cluster_size; i++) {
-               if (dic->rpages[i]) {
-                       dic->tpages[i] = dic->rpages[i];
-                       continue;
-               }
-
-               dic->tpages[i] = f2fs_compress_alloc_page();
-               if (!dic->tpages[i]) {
-                       ret = -ENOMEM;
-                       goto out_end_io;
-               }
-       }
-
-       if (cops->init_decompress_ctx) {
-               ret = cops->init_decompress_ctx(dic);
-               if (ret)
-                       goto out_end_io;
-       }
-
-       dic->rbuf = f2fs_vmap(dic->tpages, dic->cluster_size);
-       if (!dic->rbuf) {
-               ret = -ENOMEM;
-               goto out_destroy_decompress_ctx;
-       }
-
-       dic->cbuf = f2fs_vmap(dic->cpages, dic->nr_cpages);
-       if (!dic->cbuf) {
-               ret = -ENOMEM;
-               goto out_vunmap_rbuf;
+       ret = f2fs_prepare_decomp_mem(dic, false);
+       if (ret) {
+               bypass_callback = true;
+               goto out_release;
        }
 
        dic->clen = le32_to_cpu(dic->cbuf->clen);
@@ -788,7 +762,7 @@ 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 +783,13 @@ 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, false);
+
 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 +799,7 @@ out_end_io:
  * (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 +809,12 @@ 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 +1522,85 @@ destroy_out:
        return err;
 }
 
-static void f2fs_free_dic(struct decompress_io_ctx *dic);
+static inline bool allow_memalloc_for_decomp(struct f2fs_sb_info *sbi,
+               bool pre_alloc)
+{
+       return pre_alloc ^ f2fs_low_mem_mode(sbi);
+}
+
+static int f2fs_prepare_decomp_mem(struct decompress_io_ctx *dic,
+               bool pre_alloc)
+{
+       const struct f2fs_compress_ops *cops =
+               f2fs_cops[F2FS_I(dic->inode)->i_compress_algorithm];
+       int i;
+
+       if (!allow_memalloc_for_decomp(F2FS_I_SB(dic->inode), pre_alloc))
+               return 0;
+
+       dic->tpages = page_array_alloc(dic->inode, dic->cluster_size);
+       if (!dic->tpages)
+               return -ENOMEM;
+
+       for (i = 0; i < dic->cluster_size; i++) {
+               if (dic->rpages[i]) {
+                       dic->tpages[i] = dic->rpages[i];
+                       continue;
+               }
+
+               dic->tpages[i] = f2fs_compress_alloc_page();
+               if (!dic->tpages[i])
+                       return -ENOMEM;
+       }
+
+       dic->rbuf = f2fs_vmap(dic->tpages, dic->cluster_size);
+       if (!dic->rbuf)
+               return -ENOMEM;
+
+       dic->cbuf = f2fs_vmap(dic->cpages, dic->nr_cpages);
+       if (!dic->cbuf)
+               return -ENOMEM;
+
+       if (cops->init_decompress_ctx) {
+               int ret = cops->init_decompress_ctx(dic);
+
+               if (ret)
+                       return ret;
+       }
+
+       return 0;
+}
+
+static void f2fs_release_decomp_mem(struct decompress_io_ctx *dic,
+               bool bypass_destroy_callback, bool pre_alloc)
+{
+       const struct f2fs_compress_ops *cops =
+               f2fs_cops[F2FS_I(dic->inode)->i_compress_algorithm];
+
+       if (!allow_memalloc_for_decomp(F2FS_I_SB(dic->inode), pre_alloc))
+               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);
 
 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);
-       int i;
+       struct f2fs_sb_info *sbi = F2FS_I_SB(cc->inode);
+       int i, ret;
 
-       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);
 
@@ -1587,32 +1626,43 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc)
        dic->nr_rpages = cc->cluster_size;
 
        dic->cpages = page_array_alloc(dic->inode, dic->nr_cpages);
-       if (!dic->cpages)
+       if (!dic->cpages) {
+               ret = -ENOMEM;
                goto out_free;
+       }
 
        for (i = 0; i < dic->nr_cpages; i++) {
                struct page *page;
 
                page = f2fs_compress_alloc_page();
-               if (!page)
+               if (!page) {
+                       ret = -ENOMEM;
                        goto out_free;
+               }
 
                f2fs_set_compressed_page(page, cc->inode,
                                        start_idx + i + 1, dic);
                dic->cpages[i] = page;
        }
 
+       ret = f2fs_prepare_decomp_mem(dic, true);
+       if (ret)
+               goto out_free;
+
        return dic;
 
 out_free:
-       f2fs_free_dic(dic);
-       return ERR_PTR(-ENOMEM);
+       f2fs_free_dic(dic, true);
+       return ERR_PTR(ret);
 }
 
-static void f2fs_free_dic(struct decompress_io_ctx *dic)
+static void f2fs_free_dic(struct decompress_io_ctx *dic,
+               bool bypass_destroy_callback)
 {
        int i;
 
+       f2fs_release_decomp_mem(dic, bypass_destroy_callback, true);
+
        if (dic->tpages) {
                for (i = 0; i < dic->cluster_size; i++) {
                        if (dic->rpages[i])
@@ -1637,17 +1687,33 @@ static void f2fs_free_dic(struct decompress_io_ctx *dic)
        kmem_cache_free(dic_entry_slab, dic);
 }
 
-static void f2fs_put_dic(struct decompress_io_ctx *dic)
+static void f2fs_late_free_dic(struct work_struct *work)
+{
+       struct decompress_io_ctx *dic =
+               container_of(work, struct decompress_io_ctx, free_work);
+
+       f2fs_free_dic(dic, false);
+}
+
+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 +1734,7 @@ 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 +1751,15 @@ 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 +1771,7 @@ 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 +1780,12 @@ 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 b3dbe77..f48eec8 100644 (file)
--- 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)
@@ -2220,7 +2236,7 @@ skip_reading_dnode:
 
                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;
                }
 
@@ -2238,7 +2254,7 @@ submit_and_realloc:
                                        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 d187bdc..2f3c4ee 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1590,6 +1590,7 @@ 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))
@@ -4192,9 +4193,9 @@ 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,
@@ -4213,8 +4214,9 @@ 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);
@@ -4260,13 +4262,14 @@ 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);
 }