| Message ID | 20240208023254.3873823-1-chengming.zhou@linux.dev (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [mm-hotfixes-unstable] mm/zswap: invalidate duplicate entry when !zswap_enabled | expand |
On Thu, Feb 08, 2024 at 02:32:54AM +0000, chengming.zhou@linux.dev wrote: > From: Chengming Zhou <zhouchengming@bytedance.com> > > We have to invalidate any duplicate entry even when !zswap_enabled > since zswap can be disabled anytime. If the folio store success before, > then got dirtied again but zswap disabled, we won't invalidate the old > duplicate entry in the zswap_store(). So later lru writeback may > overwrite the new data in swapfile. > > Fixes: 42c06a0e8ebe ("mm: kill frontswap") > Cc: <stable@vger.kernel.org> > Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Nice, this is easier to backport and should be less disruptive to mm-unstable as well. It makes sense to me to put the optimization and cleanup that was cut out into a separate patch on top of mm-unstable. > mm/zswap.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/mm/zswap.c b/mm/zswap.c > index fe7ee2640c69..32633d0597dc 100644 > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -1516,7 +1516,7 @@ bool zswap_store(struct folio *folio) > if (folio_test_large(folio)) > return false; > > - if (!zswap_enabled || !tree) > + if (!tree) > return false; > > /* > @@ -1531,6 +1531,10 @@ bool zswap_store(struct folio *folio) > zswap_invalidate_entry(tree, dupentry); > } > spin_unlock(&tree->lock); > + > + if (!zswap_enabled) > + return false; > + > objcg = get_obj_cgroup_from_folio(folio); > if (objcg && !obj_cgroup_may_zswap(objcg)) { > memcg = get_mem_cgroup_from_objcg(objcg);
On Thu, 8 Feb 2024 02:32:54 +0000 chengming.zhou@linux.dev wrote: > From: Chengming Zhou <zhouchengming@bytedance.com> > > We have to invalidate any duplicate entry even when !zswap_enabled > since zswap can be disabled anytime. If the folio store success before, > then got dirtied again but zswap disabled, we won't invalidate the old > duplicate entry in the zswap_store(). So later lru writeback may > overwrite the new data in swapfile. > > ... > > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -1516,7 +1516,7 @@ bool zswap_store(struct folio *folio) > if (folio_test_large(folio)) > return false; > > - if (!zswap_enabled || !tree) > + if (!tree) > return false; > > /* > @@ -1531,6 +1531,10 @@ bool zswap_store(struct folio *folio) > zswap_invalidate_entry(tree, dupentry); > } > spin_unlock(&tree->lock); > + > + if (!zswap_enabled) > + return false; > + > objcg = get_obj_cgroup_from_folio(folio); > if (objcg && !obj_cgroup_may_zswap(objcg)) { > memcg = get_mem_cgroup_from_objcg(objcg); OK, thanks. I saw only one reject from mm-unstable patches. Your patch "mm/zswap: make sure each swapfile always have zswap rb-tree" now does --- a/mm/zswap.c~mm-zswap-make-sure-each-swapfile-always-have-zswap-rb-tree +++ a/mm/zswap.c @@ -1518,9 +1518,6 @@ bool zswap_store(struct folio *folio) if (folio_test_large(folio)) return false; - if (!tree) - return false; - /* * If this is a duplicate, it must be removed before attempting to store * it, otherwise, if the store fails the old page won't be removed from
On 2024/2/9 05:09, Andrew Morton wrote: > On Thu, 8 Feb 2024 02:32:54 +0000 chengming.zhou@linux.dev wrote: > >> From: Chengming Zhou <zhouchengming@bytedance.com> >> >> We have to invalidate any duplicate entry even when !zswap_enabled >> since zswap can be disabled anytime. If the folio store success before, >> then got dirtied again but zswap disabled, we won't invalidate the old >> duplicate entry in the zswap_store(). So later lru writeback may >> overwrite the new data in swapfile. >> >> ... >> >> --- a/mm/zswap.c >> +++ b/mm/zswap.c >> @@ -1516,7 +1516,7 @@ bool zswap_store(struct folio *folio) >> if (folio_test_large(folio)) >> return false; >> >> - if (!zswap_enabled || !tree) >> + if (!tree) >> return false; >> >> /* >> @@ -1531,6 +1531,10 @@ bool zswap_store(struct folio *folio) >> zswap_invalidate_entry(tree, dupentry); >> } >> spin_unlock(&tree->lock); >> + >> + if (!zswap_enabled) >> + return false; >> + >> objcg = get_obj_cgroup_from_folio(folio); >> if (objcg && !obj_cgroup_may_zswap(objcg)) { >> memcg = get_mem_cgroup_from_objcg(objcg); > > OK, thanks. > > I saw only one reject from mm-unstable patches. Your patch "mm/zswap: > make sure each swapfile always have zswap rb-tree" now does It's correct. Thanks! The other patch that includes optimization and cleanup is updated based on mm-unstable and just resend: https://lore.kernel.org/all/20240209044112.3883835-1-chengming.zhou@linux.dev/ > > --- a/mm/zswap.c~mm-zswap-make-sure-each-swapfile-always-have-zswap-rb-tree > +++ a/mm/zswap.c > @@ -1518,9 +1518,6 @@ bool zswap_store(struct folio *folio) > if (folio_test_large(folio)) > return false; > > - if (!tree) > - return false; > - > /* > * If this is a duplicate, it must be removed before attempting to store > * it, otherwise, if the store fails the old page won't be removed from > >
diff --git a/mm/zswap.c b/mm/zswap.c index fe7ee2640c69..32633d0597dc 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1516,7 +1516,7 @@ bool zswap_store(struct folio *folio) if (folio_test_large(folio)) return false; - if (!zswap_enabled || !tree) + if (!tree) return false; /* @@ -1531,6 +1531,10 @@ bool zswap_store(struct folio *folio) zswap_invalidate_entry(tree, dupentry); } spin_unlock(&tree->lock); + + if (!zswap_enabled) + return false; + objcg = get_obj_cgroup_from_folio(folio); if (objcg && !obj_cgroup_may_zswap(objcg)) { memcg = get_mem_cgroup_from_objcg(objcg);