| Message ID | 20231110033324.2455523-4-wangkefeng.wang@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: remove page idle and young wrapper | expand |
On Fri, Nov 10, 2023 at 11:33:20AM +0800, Kefeng Wang wrote: > kpageflags reads page-flags directly from the page, even when the > respective flag is only updated on the headpage of a folio. > > Since most flags are stored in head flags, make k = folio->flags, > and add new p = page->flags used for per-page flags. You'd do better to steal Greg's commit message. > Originally-from: Gregory Price <gregory.price@memverge.com> > Suggested-by: Matthew Wilcox <willy@infradead.org> > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > @@ -202,7 +202,7 @@ u64 stable_page_flags(struct page *page) > u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); > > #ifdef CONFIG_MEMORY_FAILURE > - u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison); > + u |= kpf_copy_bit(p, KPF_HWPOISON, PG_hwpoison); This is correct. > @@ -211,13 +211,13 @@ u64 stable_page_flags(struct page *page) > > u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved); > u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk); > - u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private); > - u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); > - u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); > + u |= kpf_copy_bit(p, KPF_PRIVATE, PG_private); > + u |= kpf_copy_bit(p, KPF_PRIVATE_2, PG_private_2); > + u |= kpf_copy_bit(p, KPF_OWNER_PRIVATE, PG_owner_priv_1); This is not. PG_private is not, I believe, set on tail pages. Ditto the other two. If you know differently ... ? > #ifdef CONFIG_ARCH_USES_PG_ARCH_X > - u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2); > - u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3); > + u |= kpf_copy_bit(p, KPF_ARCH_2, PG_arch_2); > + u |= kpf_copy_bit(p, KPF_ARCH_3, PG_arch_3); > #endif I also don't think this is correct, but there are many uses of PG_arch* and I may have missed something.
On 2023/11/11 2:19, Matthew Wilcox wrote: > On Fri, Nov 10, 2023 at 11:33:20AM +0800, Kefeng Wang wrote: >> kpageflags reads page-flags directly from the page, even when the >> respective flag is only updated on the headpage of a folio. >> >> Since most flags are stored in head flags, make k = folio->flags, >> and add new p = page->flags used for per-page flags. > > You'd do better to steal Greg's commit message. Sure > >> Originally-from: Gregory Price <gregory.price@memverge.com> >> Suggested-by: Matthew Wilcox <willy@infradead.org> >> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > >> @@ -202,7 +202,7 @@ u64 stable_page_flags(struct page *page) >> u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); >> >> #ifdef CONFIG_MEMORY_FAILURE >> - u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison); >> + u |= kpf_copy_bit(p, KPF_HWPOISON, PG_hwpoison); > > This is correct. > >> @@ -211,13 +211,13 @@ u64 stable_page_flags(struct page *page) >> >> u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved); >> u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk); >> - u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private); >> - u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); >> - u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); >> + u |= kpf_copy_bit(p, KPF_PRIVATE, PG_private); >> + u |= kpf_copy_bit(p, KPF_PRIVATE_2, PG_private_2); >> + u |= kpf_copy_bit(p, KPF_OWNER_PRIVATE, PG_owner_priv_1); > > This is not. PG_private is not, I believe, set on tail pages. > Ditto the other two. If you know differently ... ? k = folio->flags, p = page->flags as PG_private/private_2/owner_priv_1 use PF_ANY page policy, so they should per-page check, confused... See checked page flags, PG_error PF_NO_TAIL PG_dirty PF_HEAD PG_uptodate PF_NO_TAIL PG_writeback PF_NO_TAIL PG_lru PF_HEAD PG_referenced PF_HEAD PG_active PF_HEAD PG_reclaim PF_NO_TAIL PG_swapbacked PF_NO_TAIL PG_unevictable PF_HEAD PG_mlocked PF_NO_TAIL PG_hwpoison PF_ANY PG_uncached PF_NO_COMPOUND PG_reserved PF_NO_COMPOUND PG_mappedtodisk PF_NO_TAIL PG_private PF_ANY PG_private_2 PF_ANY PG_owner_priv_1 PF_ANY above part has 4 types, 1) PF_HEAD - should use k 2) PF_ANY - should use p 3) PF_NO_TAIL - PageXXX will check head page flags, so suppose to use k, but here use bit check, I wonder it should use p? 4) PF_NO_COMPOUND - should per-page check > >> #ifdef CONFIG_ARCH_USES_PG_ARCH_X >> - u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2); >> - u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3); >> + u |= kpf_copy_bit(p, KPF_ARCH_2, PG_arch_2); >> + u |= kpf_copy_bit(p, KPF_ARCH_3, PG_arch_3); >> #endif > > I also don't think this is correct, but there are many uses of > PG_arch* and I may have missed something. > And 3 arch page flags, PG_arch_1 - PG_dcache_clean, from achetlb.rst, I think it is per-folio, use k PG_arch_2 - only arm64 mte, PG_mte_tagged PG_arch_3 - only arm64 mte, PG_mte_lock the two PG_arch only used by arm64 mte, they are per-page flag, use p Correct me if I am wrong, thanks.
diff --git a/fs/proc/page.c b/fs/proc/page.c index dcef02471f91..553a7c921cb4 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -110,8 +110,7 @@ static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit) u64 stable_page_flags(struct page *page) { struct folio *folio; - u64 k; - u64 u; + u64 k, p, u; /* * pseudo flag: KPF_NOPAGE @@ -121,7 +120,8 @@ u64 stable_page_flags(struct page *page) return 1 << KPF_NOPAGE; folio = page_folio(page); - k = page->flags; + k = folio->flags; + p = page->flags; u = 0; /* @@ -202,7 +202,7 @@ u64 stable_page_flags(struct page *page) u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); #ifdef CONFIG_MEMORY_FAILURE - u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison); + u |= kpf_copy_bit(p, KPF_HWPOISON, PG_hwpoison); #endif #ifdef CONFIG_ARCH_USES_PG_UNCACHED @@ -211,13 +211,13 @@ u64 stable_page_flags(struct page *page) u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved); u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk); - u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private); - u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2); - u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1); + u |= kpf_copy_bit(p, KPF_PRIVATE, PG_private); + u |= kpf_copy_bit(p, KPF_PRIVATE_2, PG_private_2); + u |= kpf_copy_bit(p, KPF_OWNER_PRIVATE, PG_owner_priv_1); u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1); #ifdef CONFIG_ARCH_USES_PG_ARCH_X - u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2); - u |= kpf_copy_bit(k, KPF_ARCH_3, PG_arch_3); + u |= kpf_copy_bit(p, KPF_ARCH_2, PG_arch_2); + u |= kpf_copy_bit(p, KPF_ARCH_3, PG_arch_3); #endif return u;
kpageflags reads page-flags directly from the page, even when the respective flag is only updated on the headpage of a folio. Since most flags are stored in head flags, make k = folio->flags, and add new p = page->flags used for per-page flags. Originally-from: Gregory Price <gregory.price@memverge.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- fs/proc/page.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)