Messages in this thread Patch in this message | | | Date | Mon, 17 Apr 2023 15:15:06 +0800 | From | Yue Hu <> | Subject | Re: [PATCH] erofs: remove unneeded icur field from struct z_erofs_decompress_frontend |
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On Mon, 17 Apr 2023 15:00:25 +0800 Gao Xiang <hsiangkao@linux.alibaba.com> wrote:
> On 2023/4/17 14:52, Gao Xiang wrote: > > > > > > On 2023/4/17 14:41, Yue Hu wrote: > >> From: Yue Hu <huyue2@coolpad.com> > >> > >> The icur field is only used in z_erofs_try_inplace_io(). Let's just use > >> a local variable instead. And no need to check if the pcluster is inline > >> when setting icur since inline page cannot be used for inplace I/O. > > Where do we check if the pcluster is inline?
/* since file-backed online pages are traversed in reverse order */ fe->icur = z_erofs_pclusterpages(fe->pcl);
static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl) { if (z_erofs_is_inline_pcluster(pcl)) return 1; [...]
> > >> > >> Signed-off-by: Yue Hu <huyue2@coolpad.com> > > > > Nope, it's a behavior change. > > Other users could feed more inplace I/O pages before I/O submission > > to reduce memory consumption, it's common when applying stress model > > in low memory scenarios. > > Oh, I misread it. I think it can be done in this way although > each following users will now rescan the whole array all the time. > > Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> > > > > > Thanks, > > Gao Xiang > > > >> --- > >> fs/erofs/zdata.c | 13 +++++-------- > >> 1 file changed, 5 insertions(+), 8 deletions(-) > >> > >> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c > >> index f759152feffa..f8bf2b227942 100644 > >> --- a/fs/erofs/zdata.c > >> +++ b/fs/erofs/zdata.c > >> @@ -554,9 +554,6 @@ struct z_erofs_decompress_frontend { > >> /* used for applying cache strategy on the fly */ > >> bool backmost; > >> erofs_off_t headoffset; > >> - > >> - /* a pointer used to pick up inplace I/O pages */ > >> - unsigned int icur; > >> }; > >> #define DECOMPRESS_FRONTEND_INIT(__i) { \ > >> @@ -707,11 +704,13 @@ static bool z_erofs_try_inplace_io(struct z_erofs_decompress_frontend *fe, > >> struct z_erofs_bvec *bvec) > >> { > >> struct z_erofs_pcluster *const pcl = fe->pcl; > >> + /* file-backed online pages are traversed in reverse order */ > > Although please help refine the comment below: > > /* scan & fill inplace I/O pages in the reverse order */
Ok, will refine it in v2.
> > Thanks, > Gao Xiang > > >> + unsigned int icur = pcl->pclusterpages; > >> - while (fe->icur > 0) { > >> - if (!cmpxchg(&pcl->compressed_bvecs[--fe->icur].page, > >> + while (icur > 0) { > >> + if (!cmpxchg(&pcl->compressed_bvecs[--icur].page, > >> NULL, bvec->page)) { > >> - pcl->compressed_bvecs[fe->icur] = *bvec; > >> + pcl->compressed_bvecs[icur] = *bvec; > >> return true; > >> } > >> } > >> @@ -877,8 +876,6 @@ static int z_erofs_collector_begin(struct z_erofs_decompress_frontend *fe) > >> } > >> z_erofs_bvec_iter_begin(&fe->biter, &fe->pcl->bvset, > >> Z_EROFS_INLINE_BVECS, fe->pcl->vcnt); > >> - /* since file-backed online pages are traversed in reverse order */ > >> - fe->icur = z_erofs_pclusterpages(fe->pcl); > >> return 0; > >> }
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