Messages in this thread | | | Date | Thu, 14 Oct 2021 14:29:05 +0800 | From | Yue Hu <> | Subject | Re: [PATCH] erofs: remove the fast path of per-CPU buffer decompression |
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On Thu, 14 Oct 2021 14:16:48 +0800 Gao Xiang <hsiangkao@linux.alibaba.com> wrote:
> On Thu, Oct 14, 2021 at 01:57:56PM +0800, Yue Hu wrote: > > From: Yue Hu <huyue2@yulong.com> > > > > As Xiang mentioned, such path has no real impact to our current > > decompression strategy, remove it directly. Also, update the return > > value of z_erofs_lz4_decompress() to 0 if success to keep consistent > > with LZMA which will return 0 as well for that case. > > > > Signed-off-by: Yue Hu <huyue2@yulong.com> > > --- > > fs/erofs/decompressor.c | 64 +++++++------------------------------------------ > > 1 file changed, 8 insertions(+), 56 deletions(-) > > > > diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c > > index a5bc4b1..9905551 100644 > > --- a/fs/erofs/decompressor.c > > +++ b/fs/erofs/decompressor.c > > @@ -254,7 +254,7 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out) > > DBG_BUGON(1); > > return -EFAULT; > > } > > - return ret; > > + return ret > 0 ? 0 : ret; > > How about just updating the else branch of "if (ret != rq->outputsize)"?
Agree.
> > > } > > > > static struct z_erofs_decompressor decompressors[] = { > > @@ -268,33 +268,6 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out) > > }, > > }; > > > > -static void copy_from_pcpubuf(struct page **out, const char *dst, > > - unsigned short pageofs_out, > > - unsigned int outputsize) > > -{ > > - const char *end = dst + outputsize; > > - const unsigned int righthalf = PAGE_SIZE - pageofs_out; > > - const char *cur = dst - pageofs_out; > > - > > - while (cur < end) { > > - struct page *const page = *out++; > > - > > - if (page) { > > - char *buf = kmap_atomic(page); > > - > > - if (cur >= dst) { > > - memcpy(buf, cur, min_t(uint, PAGE_SIZE, > > - end - cur)); > > - } else { > > - memcpy(buf + pageofs_out, cur + pageofs_out, > > - min_t(uint, righthalf, end - cur)); > > - } > > - kunmap_atomic(buf); > > - } > > - cur += PAGE_SIZE; > > - } > > -} > > - > > static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, > > struct list_head *pagepool) > > { > > @@ -305,34 +278,13 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, > > void *dst; > > int ret; > > > > - /* two optimized fast paths only for non bigpcluster cases yet */ > > - if (rq->inputsize <= PAGE_SIZE) { > > - if (nrpages_out == 1 && !rq->inplace_io) { > > - DBG_BUGON(!*rq->out); > > - dst = kmap_atomic(*rq->out); > > - dst_maptype = 0; > > - goto dstmap_out; > > - } > > - > > - /* > > - * For the case of small output size (especially much less > > - * than PAGE_SIZE), memcpy the decompressed data rather than > > - * compressed data is preferred. > > - */ > > - if (rq->outputsize <= PAGE_SIZE * 7 / 8) { > > - dst = erofs_get_pcpubuf(1); > > - if (IS_ERR(dst)) > > - return PTR_ERR(dst); > > - > > - rq->inplace_io = false; > > - ret = alg->decompress(rq, dst); > > - if (!ret) > > - copy_from_pcpubuf(rq->out, dst, rq->pageofs_out, > > - rq->outputsize); > > - > > - erofs_put_pcpubuf(dst); > > - return ret; > > - } > > + /* one optimized fast path only for non bigpcluster cases yet */ > > + if (rq->inputsize <= PAGE_SIZE && > > + nrpages_out == 1 && !rq->inplace_io) { > > How about rearrange these into one line? (it seems just 80 char).
aha, seems it's.
v2 will fix them.
Thanks.
> > Otherwise looks good to me. > > Thanks, > Gao Xiang > > > + DBG_BUGON(!*rq->out); > > + dst = kmap_atomic(*rq->out); > > + dst_maptype = 0; > > + goto dstmap_out; > > } > > > > /* general decoding path which can be used for all cases */ > > -- > > 1.9.1
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