| Message ID | 20210810202936.2672-3-shy828301@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/3,linux-next] Revert "mm,shmem: fix a typo in shmem_swapin_page()" | expand |
On Tue, 10 Aug 2021, Yang Shi wrote: > Due to the change about how block layer detects congestion the > justification of commit 8fd2e0b505d1 ("mm: swap: check if swap backing device > is congested or not") doesn't stand anymore, so the commit could be just > reverted in order to solve the race reported by commit 2efa33fc7f6e ("mm/shmem: > fix shmem_swapin() race with swapoff"). The fix was reverted by the > previous patch. > > Suggested-by: Hugh Dickins <hughd@google.com> > Cc: "Huang, Ying" <ying.huang@intel.com> > Cc: Miaohe Lin <linmiaohe@huawei.com> > Signed-off-by: Yang Shi <shy828301@gmail.com> Thanks for doing these, Acked-by: Hugh Dickins <hughd@google.com> to all three. I guess 1/3 will vanish now, since what it's reverting has not yet gone forward to Linus: it would have been nice for 2/3 to have mentioned that what it's reverting is kindof buggy: but then you'd have to explain the "kindof", and that takes more words than it's worth - maybe a lore Link to the discussion? But you've done the work that I've not yet got around to: so thank you, and ignore my gripes. Hugh > --- > mm/swap_state.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/mm/swap_state.c b/mm/swap_state.c > index 1a29b4f98208..8d4104242100 100644 > --- a/mm/swap_state.c > +++ b/mm/swap_state.c > @@ -628,13 +628,6 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, > if (!mask) > goto skip; > > - /* Test swap type to make sure the dereference is safe */ > - if (likely(si->flags & (SWP_BLKDEV | SWP_FS_OPS))) { > - struct inode *inode = si->swap_file->f_mapping->host; > - if (inode_read_congested(inode)) > - goto skip; > - } > - > do_poll = false; > /* Read a page_cluster sized and aligned cluster around offset. */ > start_offset = offset & ~mask; > -- > 2.26.2
On Tue, Aug 10, 2021 at 2:08 PM Hugh Dickins <hughd@google.com> wrote: > > On Tue, 10 Aug 2021, Yang Shi wrote: > > > Due to the change about how block layer detects congestion the > > justification of commit 8fd2e0b505d1 ("mm: swap: check if swap backing device > > is congested or not") doesn't stand anymore, so the commit could be just > > reverted in order to solve the race reported by commit 2efa33fc7f6e ("mm/shmem: > > fix shmem_swapin() race with swapoff"). The fix was reverted by the > > previous patch. > > > > Suggested-by: Hugh Dickins <hughd@google.com> > > Cc: "Huang, Ying" <ying.huang@intel.com> > > Cc: Miaohe Lin <linmiaohe@huawei.com> > > Signed-off-by: Yang Shi <shy828301@gmail.com> > > Thanks for doing these, > Acked-by: Hugh Dickins <hughd@google.com> > to all three. > > I guess 1/3 will vanish now, since what it's reverting has not yet gone > forward to Linus: it would have been nice for 2/3 to have mentioned that > what it's reverting is kindof buggy: but then you'd have to explain the > "kindof", and that takes more words than it's worth - maybe a lore Link > to the discussion? It is fine, I think this one is the best elaborated the problem: https://lore.kernel.org/linux-mm/24187e5e-069-9f3f-cefe-39ac70783753@google.com/ > > But you've done the work that I've not yet got around to: > so thank you, and ignore my gripes. > > Hugh > > > --- > > mm/swap_state.c | 7 ------- > > 1 file changed, 7 deletions(-) > > > > diff --git a/mm/swap_state.c b/mm/swap_state.c > > index 1a29b4f98208..8d4104242100 100644 > > --- a/mm/swap_state.c > > +++ b/mm/swap_state.c > > @@ -628,13 +628,6 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, > > if (!mask) > > goto skip; > > > > - /* Test swap type to make sure the dereference is safe */ > > - if (likely(si->flags & (SWP_BLKDEV | SWP_FS_OPS))) { > > - struct inode *inode = si->swap_file->f_mapping->host; > > - if (inode_read_congested(inode)) > > - goto skip; > > - } > > - > > do_poll = false; > > /* Read a page_cluster sized and aligned cluster around offset. */ > > start_offset = offset & ~mask; > > -- > > 2.26.2
On Tue, 10 Aug 2021, Yang Shi wrote: > On Tue, Aug 10, 2021 at 2:08 PM Hugh Dickins <hughd@google.com> wrote: > > > > I guess 1/3 will vanish now, since what it's reverting has not yet gone > > forward to Linus: it would have been nice for 2/3 to have mentioned that > > what it's reverting is kindof buggy: but then you'd have to explain the > > "kindof", and that takes more words than it's worth - maybe a lore Link > > to the discussion? > > It is fine, I think this one is the best elaborated the problem: > https://lore.kernel.org/linux-mm/24187e5e-069-9f3f-cefe-39ac70783753@google.com/ Yes, that best elaborated the problem when I thought it was a problem, then https://lore.kernel.org/linux-mm/e82380b9-3ad4-4a52-be50-6d45c7f2b5da@google.com/ explained why I later came to think that it wasn't a problem after all. Hence "kindof" buggy: but good to be reverted anyway. Whatever! Thanks, Hugh
diff --git a/mm/swap_state.c b/mm/swap_state.c index 1a29b4f98208..8d4104242100 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -628,13 +628,6 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, if (!mask) goto skip; - /* Test swap type to make sure the dereference is safe */ - if (likely(si->flags & (SWP_BLKDEV | SWP_FS_OPS))) { - struct inode *inode = si->swap_file->f_mapping->host; - if (inode_read_congested(inode)) - goto skip; - } - do_poll = false; /* Read a page_cluster sized and aligned cluster around offset. */ start_offset = offset & ~mask;
Due to the change about how block layer detects congestion the justification of commit 8fd2e0b505d1 ("mm: swap: check if swap backing device is congested or not") doesn't stand anymore, so the commit could be just reverted in order to solve the race reported by commit 2efa33fc7f6e ("mm/shmem: fix shmem_swapin() race with swapoff"). The fix was reverted by the previous patch. Suggested-by: Hugh Dickins <hughd@google.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Yang Shi <shy828301@gmail.com> --- mm/swap_state.c | 7 ------- 1 file changed, 7 deletions(-)