Messages in this thread Patch in this message | | | Date | Mon, 17 Apr 2023 15:00:25 +0800 | Subject | Re: [PATCH] erofs: remove unneeded icur field from struct z_erofs_decompress_frontend | From | Gao Xiang <> |
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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?
>> >> 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 */
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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