> -----Original Message-----
> From: [email protected] <[email protected]> On Behalf Of
> Chao Yu
> Sent: Tuesday, November 9, 2021 10:11 PM
> To: 常凤楠 <[email protected]>; [email protected]
> Cc: [email protected]
> Subject: Re: [PATCH v2] f2fs: compress: reduce one page array alloc and
> free when write compressed page
>
> On 2021/11/9 11:54, Fengnan Chang wrote:
> > Don't alloc new page pointers array to replace old, just use old,
> > introduce valid_nr_cpages to indicate valid number of page pointers in
> > array, try to reduce one page array alloc and free when write compress
> page.
> >
> > Signed-off-by: Fengnan Chang <[email protected]>
> > ---
> > fs/f2fs/compress.c | 27 +++++++++------------------
> > fs/f2fs/data.c | 1 +
> > fs/f2fs/f2fs.h | 1 +
> > 3 files changed, 11 insertions(+), 18 deletions(-)
> >
> > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index
> > 9b663eaf4805..28785dd78c6f 100644
> > --- a/fs/f2fs/compress.c
> > +++ b/fs/f2fs/compress.c
> > @@ -153,6 +153,7 @@ void f2fs_destroy_compress_ctx(struct
> compress_ctx *cc, bool reuse)
> > cc->rpages = NULL;
> > cc->nr_rpages = 0;
> > cc->nr_cpages = 0;
> > + cc->valid_nr_cpages = 0;
> > if (!reuse)
> > cc->cluster_idx = NULL_CLUSTER;
> > }
> > @@ -619,7 +620,6 @@ static int f2fs_compress_pages(struct
> compress_ctx *cc)
> > const struct f2fs_compress_ops *cops =
> > f2fs_cops[fi->i_compress_algorithm];
> > unsigned int max_len, new_nr_cpages;
> > - struct page **new_cpages;
> > u32 chksum = 0;
> > int i, ret;
> >
> > @@ -634,6 +634,7 @@ static int f2fs_compress_pages(struct
> compress_ctx
> > *cc)
> >
> > max_len = COMPRESS_HEADER_SIZE + cc->clen;
> > cc->nr_cpages = DIV_ROUND_UP(max_len, PAGE_SIZE);
> > + cc->valid_nr_cpages = cc->nr_cpages;
> >
> > cc->cpages = page_array_alloc(cc->inode, cc->nr_cpages);
> > if (!cc->cpages) {
> > @@ -684,13 +685,6 @@ static int f2fs_compress_pages(struct
> > compress_ctx *cc)
> >
> > new_nr_cpages = DIV_ROUND_UP(cc->clen +
> COMPRESS_HEADER_SIZE,
> > PAGE_SIZE);
> >
> > - /* Now we're going to cut unnecessary tail pages */
> > - new_cpages = page_array_alloc(cc->inode, new_nr_cpages);
> > - if (!new_cpages) {
> > - ret = -ENOMEM;
> > - goto out_vunmap_cbuf;
>
> It removes last user of out_vunmap_cbuf label, so we can remove below
> dead codes in error path as well.
>
> out_vunmap_cbuf:
> vm_unmap_ram(cc->cbuf, cc->nr_cpages);
Not right, there still other code use this.
Thanks.
>
> > - }
> > -
> > /* zero out any unused part of the last page */
> > memset(&cc->cbuf->cdata[cc->clen], 0,
> > (new_nr_cpages * PAGE_SIZE) -
> > @@ -701,7 +695,6 @@ static int f2fs_compress_pages(struct
> compress_ctx
> > *cc)
> >
> > for (i = 0; i < cc->nr_cpages; i++) {
> > if (i < new_nr_cpages) {
> > - new_cpages[i] = cc->cpages[i];
> > continue;
> > }
>
> if (i < new_nr_cpages)
> continue;
>
> > f2fs_compress_free_page(cc->cpages[i]);
> > @@ -711,9 +704,7 @@ static int f2fs_compress_pages(struct
> compress_ctx *cc)
> > if (cops->destroy_compress_ctx)
> > cops->destroy_compress_ctx(cc);
> >
> > - page_array_free(cc->inode, cc->cpages, cc->nr_cpages);
> > - cc->cpages = new_cpages;
> > - cc->nr_cpages = new_nr_cpages;
> > + cc->valid_nr_cpages = new_nr_cpages;
> >
> > trace_f2fs_compress_pages_end(cc->inode, cc->cluster_idx,
> > cc->clen, ret);
> > @@ -1288,14 +1279,14 @@ static int
> f2fs_write_compressed_pages(struct
> > compress_ctx *cc,
> >
> > cic->magic = F2FS_COMPRESSED_PAGE_MAGIC;
> > cic->inode = inode;
> > - atomic_set(&cic->pending_pages, cc->nr_cpages);
> > + atomic_set(&cic->pending_pages, cc->valid_nr_cpages);
> > cic->rpages = page_array_alloc(cc->inode, cc->cluster_size);
> > if (!cic->rpages)
> > goto out_put_cic;
> >
> > cic->nr_rpages = cc->cluster_size;
> >
> > - for (i = 0; i < cc->nr_cpages; i++) {
> > + for (i = 0; i < cc->valid_nr_cpages; i++) {
> > f2fs_set_compressed_page(cc->cpages[i], inode,
> > cc->rpages[i + 1]->index, cic);
> > fio.compressed_page = cc->cpages[i]; @@ -1340,7 +1331,7
> @@ static
> > int f2fs_write_compressed_pages(struct compress_ctx *cc,
> > if (fio.compr_blocks && __is_valid_data_blkaddr(blkaddr))
> > fio.compr_blocks++;
> >
> > - if (i > cc->nr_cpages) {
> > + if (i > cc->valid_nr_cpages) {
> > if (__is_valid_data_blkaddr(blkaddr)) {
> > f2fs_invalidate_blocks(sbi, blkaddr);
> > f2fs_update_data_blkaddr(&dn, NEW_ADDR); @@
> -1365,8 +1356,8 @@
> > static int f2fs_write_compressed_pages(struct compress_ctx *cc,
> >
> > if (fio.compr_blocks)
> > f2fs_i_compr_blocks_update(inode, fio.compr_blocks - 1,
> false);
> > - f2fs_i_compr_blocks_update(inode, cc->nr_cpages, true);
> > - add_compr_block_stat(inode, cc->nr_cpages);
> > + f2fs_i_compr_blocks_update(inode, cc->valid_nr_cpages, true);
> > + add_compr_block_stat(inode, cc->valid_nr_cpages);
> >
> > set_inode_flag(cc->inode, FI_APPEND_WRITE);
> > if (cc->cluster_idx == 0)
> > @@ -1404,7 +1395,7 @@ static int f2fs_write_compressed_pages(struct
> compress_ctx *cc,
> > else
> > f2fs_unlock_op(sbi);
> > out_free:
> > - for (i = 0; i < cc->nr_cpages; i++) {
> > + for (i = 0; i < cc->valid_nr_cpages; i++) {
> > if (!cc->cpages[i])
> > continue;
>
> We can remove above cpages check?
>
> Thanks,
>
> > f2fs_compress_free_page(cc->cpages[i]);
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index
> > f4fd6c246c9a..4ddc0ba0f2c0 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -2934,6 +2934,7 @@ static int f2fs_write_cache_pages(struct
> address_space *mapping,
> > .rpages = NULL,
> > .nr_rpages = 0,
> > .cpages = NULL,
> > + .valid_nr_cpages = 0,
> > .rbuf = NULL,
> > .cbuf = NULL,
> > .rlen = PAGE_SIZE * F2FS_I(inode)->i_cluster_size, diff --git
> > a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 039a229e11c9..acb587f054db
> > 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -1481,6 +1481,7 @@ struct compress_ctx {
> > unsigned int nr_rpages; /* total page number in rpages
> */
> > struct page **cpages; /* pages store compressed data in
> cluster */
> > unsigned int nr_cpages; /* total page number in cpages
> */
> > + unsigned int valid_nr_cpages; /* valid page number in cpages */
> > void *rbuf; /* virtual mapped address on rpages */
> > struct compress_data *cbuf; /* virtual mapped address on
> cpages */
> > size_t rlen; /* valid data length in rbuf */
> >
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