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erofs: try to leave (de)compressed_pages on stack if possible 

For the most cases, small pclusters can be decompressed with page
arrays on stack.

Try to leave both (de)compressed_pages on stack if possible as before.

Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-14-hsiangkao@linux.alibaba.com
This commit is contained in:
Gao Xiang 2022-07-15 23:42:00 +08:00
parent 4f05687fd7
commit fe3e5914e6
1 changed files with 21 additions and 13 deletions
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34
fs/erofs/zdata.c
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@ -858,6 +858,7 @@ struct z_erofs_decompress_backend {
struct page **compressed_pages;
struct page **pagepool;
unsigned int onstack_used;
};
static int z_erofs_parse_out_bvecs(struct z_erofs_decompress_backend *be)
@ -904,14 +905,9 @@ static int z_erofs_parse_in_bvecs(struct z_erofs_decompress_backend *be,
{
struct z_erofs_pcluster *pcl = be->pcl;
unsigned int pclusterpages = z_erofs_pclusterpages(pcl);
struct page **compressed_pages;
int i, err = 0;
/* XXX: will have a better approach in the following commits */
compressed_pages = kmalloc_array(pclusterpages, sizeof(struct page *),
GFP_KERNEL | __GFP_NOFAIL);
*overlapped = false;
for (i = 0; i < pclusterpages; ++i) {
struct z_erofs_bvec *bvec = &pcl->compressed_bvecs[i];
struct page *page = bvec->page;
@ -922,7 +918,7 @@ static int z_erofs_parse_in_bvecs(struct z_erofs_decompress_backend *be,
DBG_BUGON(1);
continue;
}
compressed_pages[i] = page;
be->compressed_pages[i] = page;
if (z_erofs_is_inline_pcluster(pcl)) {
if (!PageUptodate(page))
@ -953,11 +949,8 @@ static int z_erofs_parse_in_bvecs(struct z_erofs_decompress_backend *be,
}
}
if (err) {
kfree(compressed_pages);
if (err)
return err;
}
be->compressed_pages = compressed_pages;
return 0;
}
@ -976,15 +969,28 @@ static int z_erofs_decompress_pcluster(struct z_erofs_decompress_backend *be,
mutex_lock(&pcl->lock);
nr_pages = pcl->nr_pages;
/* allocate (de)compressed page arrays if cannot be kept on stack */
be->decompressed_pages = NULL;
be->compressed_pages = NULL;
be->onstack_used = 0;
if (nr_pages <= Z_EROFS_ONSTACK_PAGES) {
be->decompressed_pages = be->onstack_pages;
be->onstack_used = nr_pages;
memset(be->decompressed_pages, 0,
sizeof(struct page *) * nr_pages);
} else {
}
if (pclusterpages + be->onstack_used <= Z_EROFS_ONSTACK_PAGES)
be->compressed_pages = be->onstack_pages + be->onstack_used;
if (!be->decompressed_pages)
be->decompressed_pages =
kvcalloc(nr_pages, sizeof(struct page *),
GFP_KERNEL | __GFP_NOFAIL);
}
if (!be->compressed_pages)
be->compressed_pages =
kvcalloc(pclusterpages, sizeof(struct page *),
GFP_KERNEL | __GFP_NOFAIL);
err2 = z_erofs_parse_out_bvecs(be);
if (err2)
@ -1041,7 +1047,9 @@ out:
WRITE_ONCE(pcl->compressed_bvecs[i].page, NULL);
}
}
kfree(be->compressed_pages);
if (be->compressed_pages < be->onstack_pages ||
be->compressed_pages >= be->onstack_pages + Z_EROFS_ONSTACK_PAGES)
kvfree(be->compressed_pages);
for (i = 0; i < nr_pages; ++i) {
page = be->decompressed_pages[i];