2020-09-19 07:29:49

by Gao Xiang

[permalink] [raw]
Subject: [PATCH v2 1/3] erofs: avoid unnecessary variable `err'

variable `err' in z_erofs_submit_queue() isn't useful
here, remove it instead.

Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Gao Xiang <[email protected]>
---
no change since v1.

fs/erofs/zdata.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index ac6cb73df192..e43684b23fdd 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1190,7 +1190,6 @@ static void z_erofs_submit_queue(struct super_block *sb,

do {
struct page *page;
- int err;

page = pickup_page_for_submission(pcl, i++, pagepool,
MNGD_MAPPING(sbi),
@@ -1216,8 +1215,7 @@ static void z_erofs_submit_queue(struct super_block *sb,
++nr_bios;
}

- err = bio_add_page(bio, page, PAGE_SIZE, 0);
- if (err < PAGE_SIZE)
+ if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE)
goto submit_bio_retry;

last_index = cur;
--
2.18.1


2020-09-19 07:31:18

by Gao Xiang

[permalink] [raw]
Subject: [PATCH v2 2/3] erofs: fold in should_decompress_synchronously()

should_decompress_synchronously() has one single condition
for now, so fold it instead.

Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Gao Xiang <[email protected]>
---
no change since v1.

fs/erofs/zdata.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index e43684b23fdd..bee6ce783c64 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1294,24 +1294,18 @@ static int z_erofs_readpage(struct file *file, struct page *page)
return err;
}

-static bool should_decompress_synchronously(struct erofs_sb_info *sbi,
- unsigned int nr)
-{
- return nr <= sbi->ctx.max_sync_decompress_pages;
-}
-
static void z_erofs_readahead(struct readahead_control *rac)
{
struct inode *const inode = rac->mapping->host;
struct erofs_sb_info *const sbi = EROFS_I_SB(inode);

- bool sync = should_decompress_synchronously(sbi, readahead_count(rac));
+ unsigned int nr_pages = readahead_count(rac);
+ bool sync = (nr_pages <= sbi->ctx.max_sync_decompress_pages);
struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
struct page *page, *head = NULL;
LIST_HEAD(pagepool);

- trace_erofs_readpages(inode, readahead_index(rac),
- readahead_count(rac), false);
+ trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false);

f.headoffset = readahead_pos(rac);

--
2.18.1

2020-09-19 07:32:39

by Gao Xiang

[permalink] [raw]
Subject: [PATCH v2 3/3] erofs: add REQ_RAHEAD flag to readahead requests

Let's add REQ_RAHEAD flag so it'd be easier to identify
readahead I/O requests in blktrace.

Reviewed-by: Chao Yu <[email protected]>
Signed-off-by: Gao Xiang <[email protected]>
---
change since v1:
since "erofs: add REQ_RAHEAD flag to readahead requests" is dropped,
lifting up related code to this patch and rebase for now.

fs/erofs/data.c | 2 +-
fs/erofs/zdata.c | 17 +++++++++++------
2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 459ecb42cbd3..347be146884c 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -224,7 +224,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
bio_set_dev(bio, sb->s_bdev);
bio->bi_iter.bi_sector = (sector_t)blknr <<
LOG_SECTORS_PER_BLOCK;
- bio->bi_opf = REQ_OP_READ;
+ bio->bi_opf = REQ_OP_READ | (ra ? REQ_RAHEAD : 0);
}

err = bio_add_page(bio, page, PAGE_SIZE, 0);
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index bee6ce783c64..50912a5420b4 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -135,6 +135,7 @@ struct z_erofs_decompress_frontend {
struct z_erofs_collector clt;
struct erofs_map_blocks map;

+ bool readahead;
/* used for applying cache strategy on the fly */
bool backmost;
erofs_off_t headoffset;
@@ -1148,7 +1149,7 @@ static void move_to_bypass_jobqueue(struct z_erofs_pcluster *pcl,
}

static void z_erofs_submit_queue(struct super_block *sb,
- z_erofs_next_pcluster_t owned_head,
+ struct z_erofs_decompress_frontend *f,
struct list_head *pagepool,
struct z_erofs_decompressqueue *fgq,
bool *force_fg)
@@ -1157,6 +1158,7 @@ static void z_erofs_submit_queue(struct super_block *sb,
z_erofs_next_pcluster_t qtail[NR_JOBQUEUES];
struct z_erofs_decompressqueue *q[NR_JOBQUEUES];
void *bi_private;
+ z_erofs_next_pcluster_t owned_head = f->clt.owned_head;
/* since bio will be NULL, no need to initialize last_index */
pgoff_t last_index;
unsigned int nr_bios = 0;
@@ -1212,6 +1214,8 @@ static void z_erofs_submit_queue(struct super_block *sb,
LOG_SECTORS_PER_BLOCK;
bio->bi_private = bi_private;
bio->bi_opf = REQ_OP_READ;
+ if (f->readahead)
+ bio->bi_opf |= REQ_RAHEAD;
++nr_bios;
}

@@ -1243,14 +1247,14 @@ static void z_erofs_submit_queue(struct super_block *sb,
}

static void z_erofs_runqueue(struct super_block *sb,
- struct z_erofs_collector *clt,
+ struct z_erofs_decompress_frontend *f,
struct list_head *pagepool, bool force_fg)
{
struct z_erofs_decompressqueue io[NR_JOBQUEUES];

- if (clt->owned_head == Z_EROFS_PCLUSTER_TAIL)
+ if (f->clt.owned_head == Z_EROFS_PCLUSTER_TAIL)
return;
- z_erofs_submit_queue(sb, clt->owned_head, pagepool, io, &force_fg);
+ z_erofs_submit_queue(sb, f, pagepool, io, &force_fg);

/* handle bypass queue (no i/o pclusters) immediately */
z_erofs_decompress_queue(&io[JQ_BYPASS], pagepool);
@@ -1281,7 +1285,7 @@ static int z_erofs_readpage(struct file *file, struct page *page)
(void)z_erofs_collector_end(&f.clt);

/* if some compressed cluster ready, need submit them anyway */
- z_erofs_runqueue(inode->i_sb, &f.clt, &pagepool, true);
+ z_erofs_runqueue(inode->i_sb, &f, &pagepool, true);

if (err)
erofs_err(inode->i_sb, "failed to read, err [%d]", err);
@@ -1307,6 +1311,7 @@ static void z_erofs_readahead(struct readahead_control *rac)

trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false);

+ f.readahead = true;
f.headoffset = readahead_pos(rac);

while ((page = readahead_page(rac))) {
@@ -1340,7 +1345,7 @@ static void z_erofs_readahead(struct readahead_control *rac)

(void)z_erofs_collector_end(&f.clt);

- z_erofs_runqueue(inode->i_sb, &f.clt, &pagepool, sync);
+ z_erofs_runqueue(inode->i_sb, &f, &pagepool, sync);

if (f.map.mpage)
put_page(f.map.mpage);
--
2.18.1