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Date: Fri, 10 Dec 2021 09:19:50 +0800 From: Zhaoyang Huang <huangzhaoyang@...il.com> To: David Howells <dhowells@...hat.com> Cc: Marc Dionne <marc.dionne@...istor.com>, Zhaoyang Huang <zhaoyang.huang@...soc.com>, linux-cachefs@...hat.com, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] fs: judging context via current_is_kswapd instead of gfp_flag On Thu, Dec 9, 2021 at 4:26 AM David Howells <dhowells@...hat.com> wrote: > > Huangzhaoyang <huangzhaoyang@...il.com> wrote: > > [adding linux-cachefs to the cc list] > > > Kswapd uses GFP_KERNEL as gfp_flag which make the judgment of > > context is unexpected. fix it by using current_is_kswapd. > > > > Signed-off-by: Zhaoyang Huang <zhaoyang.huang@...soc.com> > > --- > > fs/afs/file.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/fs/afs/file.c b/fs/afs/file.c > > index eb11d04..6c199d5 100644 > > --- a/fs/afs/file.c > > +++ b/fs/afs/file.c > > @@ -485,7 +485,7 @@ static int afs_releasepage(struct page *page, gfp_t gfp_flags) > > * elected to wait */ > > #ifdef CONFIG_AFS_FSCACHE > > if (PageFsCache(page)) { > > - if (!(gfp_flags & __GFP_DIRECT_RECLAIM) || !(gfp_flags & __GFP_FS)) > > + if (current_is_kswapd() || !(gfp_flags & __GFP_FS)) > > return false; > > wait_on_page_fscache(page); > > } > > I have several of these in my fscache-rewrite branch, spread across a number > of filesystems. Should I fix all of them the same way? > > fs/9p/vfs_addr.c: if (!gfpflags_allow_blocking(gfp) || !(gfp & __GFP_FS)) > fs/afs/file.c: if (!gfpflags_allow_blocking(gfp) || !(gfp & __GFP_FS)) > fs/nfs/file.c: if (!gfpflags_allow_blocking(gfp) || !(gfp & __GFP_FS)) > fs/nfs/fscache.h: if (!gfpflags_allow_blocking(gfp) || !(gfp & __GFP_FS)) > > David If the gfp flag here is used for judging kswapd context, I think the answer is yes as kswapd applied __GFP_DIRECT_RECLAIM. >
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