search for: declare_static_key_false

On 07.02.23 22:09, Srivatsa S. Bhat wrote: > On 2/6/23 11:59 PM, Juergen Gross wrote: >> The two paravirt callbacks .mmu.activate_mm and .mmu.dup_mmap are >> sharing the same implementations in all cases: for Xen PV guests they >> are pinning the PGD of the new mm_struct, and for all other cases >> they are a NOP. >> >> In the end both callbacks are meant to

...PDX-License-Identifier: GPL-2.0-or-later */ +#ifndef __ASM_PARAVIRT_H +#define __ASM_PARAVIRT_H +#ifdef __KERNEL__ + +#include <linux/jump_label.h> +#include <asm/smp.h> +#ifdef CONFIG_PPC64 +#include <asm/paca.h> +#include <asm/hvcall.h> +#endif + +#ifdef CONFIG_PPC_SPLPAR +DECLARE_STATIC_KEY_FALSE(shared_processor); + +static inline bool is_shared_processor(void) +{ + return static_branch_unlikely(&shared_processor); +} + +/* If bit 0 is set, the cpu has been preempted */ +static inline u32 yield_count_of(int cpu) +{ + __be32 yield_count = READ_ONCE(lppaca_of(cpu).yield_count); + return...

...mm.h > index 517751310dd2..5a82037a4b26 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1093,34 +1093,6 @@ static inline bool is_zone_device_page(const struct page *page) > #ifdef CONFIG_DEV_PAGEMAP_OPS > void free_devmap_managed_page(struct page *page); > DECLARE_STATIC_KEY_FALSE(devmap_managed_key); The export for devmap_managed_key can be dropped now. In fact I think we can remove devmap_managed_key entirely now - it is only checked in the actual page free path instead of for each refcount manipulation, so a good old unlikely is probably enough. Also free_devmap_manage...

...2..5a82037a4b26 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -1093,34 +1093,6 @@ static inline bool is_zone_device_page(const struct page *page) >> #ifdef CONFIG_DEV_PAGEMAP_OPS >> void free_devmap_managed_page(struct page *page); >> DECLARE_STATIC_KEY_FALSE(devmap_managed_key); > > The export for devmap_managed_key can be dropped now. In fact I think > we can remove devmap_managed_key entirely now - it is only checked in > the actual page free path instead of for each refcount manipulation, > so a good old unlikely is probably enough....

...dec_return(nmi_state)) I really hate all this #VC stuff :-( So the above will make the NMI do 4 unconditional extra CALL+RET, a LOAD (which will potentially miss) and a compare and branch. How's that a win for normal people? Can we please turn all these sev_es_*() hooks into something like: DECLARE_STATIC_KEY_FALSE(sev_es_enabled_key); static __always_inline void sev_es_foo() { if (static_branch_unlikely(&sev_es_enabled_key)) __sev_es_foo(); } So that normal people will only see an extra NOP? > diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c > index d415368f16ec..2a7cc72db1d5...

...dec_return(nmi_state)) I really hate all this #VC stuff :-( So the above will make the NMI do 4 unconditional extra CALL+RET, a LOAD (which will potentially miss) and a compare and branch. How's that a win for normal people? Can we please turn all these sev_es_*() hooks into something like: DECLARE_STATIC_KEY_FALSE(sev_es_enabled_key); static __always_inline void sev_es_foo() { if (static_branch_unlikely(&sev_es_enabled_key)) __sev_es_foo(); } So that normal people will only see an extra NOP? > diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c > index d415368f16ec..2a7cc72db1d5...

...include/linux/mm.h b/include/linux/mm.h index 517751310dd2..5a82037a4b26 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1093,34 +1093,6 @@ static inline bool is_zone_device_page(const struct page *page) #ifdef CONFIG_DEV_PAGEMAP_OPS void free_devmap_managed_page(struct page *page); DECLARE_STATIC_KEY_FALSE(devmap_managed_key); - -static inline bool page_is_devmap_managed(struct page *page) -{ - if (!static_branch_unlikely(&devmap_managed_key)) - return false; - if (!is_zone_device_page(page)) - return false; - switch (page->pgmap->type) { - case MEMORY_DEVICE_PRIVATE: - case MEMORY_DEVICE...

.....2159c2477aa3 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1092,39 +1092,6 @@ static inline bool is_zone_device_page(const struct page *page) > } > #endif > > -#ifdef CONFIG_DEV_PAGEMAP_OPS > -void free_devmap_managed_page(struct page *page); > -DECLARE_STATIC_KEY_FALSE(devmap_managed_key); > - > -static inline bool page_is_devmap_managed(struct page *page) > -{ > - if (!static_branch_unlikely(&devmap_managed_key)) > - return false; > - if (!is_zone_device_page(page)) > - return false; > - switch (page->pgmap->type) { > - cas...

...;sk_validate_xmit_skb' not described in 'sock' include/net/sock.h:515: warning: Function parameter or member 'sk_bpf_storage' not described in 'sock' include/net/sock.h:2439: warning: Function parameter or member 'tcp_rx_skb_cache_key' not described in 'DECLARE_STATIC_KEY_FALSE' include/net/sock.h:2439: warning: Excess function parameter 'sk' description in 'DECLARE_STATIC_KEY_FALSE' include/net/sock.h:2439: warning: Excess function parameter 'skb' description in 'DECLARE_STATIC_KEY_FALSE' include/linux/netdevice.h:2040: warnin...

On Wed, Jul 15, 2020 at 11:47:02AM +0200, Peter Zijlstra wrote: > On Tue, Jul 14, 2020 at 02:08:47PM +0200, Joerg Roedel wrote: > DECLARE_STATIC_KEY_FALSE(sev_es_enabled_key); > > static __always_inline void sev_es_foo() > { > if (static_branch_unlikely(&sev_es_enabled_key)) > __sev_es_foo(); > } > > So that normal people will only see an extra NOP? Yes, that is a good idea, I will use a static key for these cases....

...00644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -921,8 +921,6 @@ static inline bool is_zone_device_page(const struct page *page) #endif #ifdef CONFIG_DEV_PAGEMAP_OPS -void dev_pagemap_get_ops(void); -void dev_pagemap_put_ops(void); void __put_devmap_managed_page(struct page *page); DECLARE_STATIC_KEY_FALSE(devmap_managed_key); static inline bool put_devmap_managed_page(struct page *page) @@ -969,14 +967,6 @@ static inline bool is_pci_p2pdma_page(const struct page *page) #endif /* CONFIG_PCI_P2PDMA */ #else /* CONFIG_DEV_PAGEMAP_OPS */ -static inline void dev_pagemap_get_ops(void) -{ -} - -static...

...00644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -921,8 +921,6 @@ static inline bool is_zone_device_page(const struct page *page) #endif #ifdef CONFIG_DEV_PAGEMAP_OPS -void dev_pagemap_get_ops(void); -void dev_pagemap_put_ops(void); void __put_devmap_managed_page(struct page *page); DECLARE_STATIC_KEY_FALSE(devmap_managed_key); static inline bool put_devmap_managed_page(struct page *page) @@ -969,14 +967,6 @@ static inline bool is_pci_p2pdma_page(const struct page *page) #endif /* CONFIG_PCI_P2PDMA */ #else /* CONFIG_DEV_PAGEMAP_OPS */ -static inline void dev_pagemap_get_ops(void) -{ -} - -static...

...00644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -932,8 +932,6 @@ static inline bool is_zone_device_page(const struct page *page) #endif #ifdef CONFIG_DEV_PAGEMAP_OPS -void dev_pagemap_get_ops(void); -void dev_pagemap_put_ops(void); void __put_devmap_managed_page(struct page *page); DECLARE_STATIC_KEY_FALSE(devmap_managed_key); static inline bool put_devmap_managed_page(struct page *page) @@ -973,14 +971,6 @@ static inline bool is_pci_p2pdma_page(const struct page *page) #endif /* CONFIG_PCI_P2PDMA */ #else /* CONFIG_DEV_PAGEMAP_OPS */ -static inline void dev_pagemap_get_ops(void) -{ -} - -static...

...lude/linux/mm.h > @@ -932,8 +932,6 @@ static inline bool is_zone_device_page(const struct page *page) > #endif > > #ifdef CONFIG_DEV_PAGEMAP_OPS > -void dev_pagemap_get_ops(void); > -void dev_pagemap_put_ops(void); > void __put_devmap_managed_page(struct page *page); > DECLARE_STATIC_KEY_FALSE(devmap_managed_key); > static inline bool put_devmap_managed_page(struct page *page) > @@ -973,14 +971,6 @@ static inline bool is_pci_p2pdma_page(const struct page *page) > #endif /* CONFIG_PCI_P2PDMA */ > > #else /* CONFIG_DEV_PAGEMAP_OPS */ > -static inline void dev_pagemap...

Matthew Wilcox, Ira Weiny, and others have complained that ZONE_DEVICE struct page reference counting is ugly because they are "free" when the reference count is one instead of zero. This leads to explicit checks for ZONE_DEVICE pages in places like put_page(), GUP, THP splitting, and page migration which have to adjust the expected reference count when determining if the page is

Many DRM drivers implement an encoder with an empty implementation. This patchset adds drm_simple_encoder_init() and drm_simple_encoder_create(), which can be used by drivers instead. Except for the destroy callback, the simple encoder's implementation is empty. The patchset also converts 4 encoder instances to use the simple-encoder helpers. But there are at least 11 other drivers which can

.../mm.h b/include/linux/mm.h index b2f370f0b420..2159c2477aa3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1092,39 +1092,6 @@ static inline bool is_zone_device_page(const struct page *page) } #endif -#ifdef CONFIG_DEV_PAGEMAP_OPS -void free_devmap_managed_page(struct page *page); -DECLARE_STATIC_KEY_FALSE(devmap_managed_key); - -static inline bool page_is_devmap_managed(struct page *page) -{ - if (!static_branch_unlikely(&devmap_managed_key)) - return false; - if (!is_zone_device_page(page)) - return false; - switch (page->pgmap->type) { - case MEMORY_DEVICE_PRIVATE: - case MEMORY_DEVICE...

.../mm.h b/include/linux/mm.h index 27c64d0d7520..3d71a820ae38 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1100,39 +1100,6 @@ static inline bool is_zone_device_page(const struct page *page) } #endif -#ifdef CONFIG_DEV_PAGEMAP_OPS -void free_devmap_managed_page(struct page *page); -DECLARE_STATIC_KEY_FALSE(devmap_managed_key); - -static inline bool page_is_devmap_managed(struct page *page) -{ - if (!static_branch_unlikely(&devmap_managed_key)) - return false; - if (!is_zone_device_page(page)) - return false; - switch (page->pgmap->type) { - case MEMORY_DEVICE_PRIVATE: - case MEMORY_DEVICE...

v2 is updated to account for feedback from Will, Peter, and Waiman (thank you), and trims off a couple of RFC and unrelated patches. Thanks, Nick Nicholas Piggin (6): powerpc/powernv: must include hvcall.h to get PAPR defines powerpc/pseries: move some PAPR paravirt functions to their own file powerpc: move spinlock implementation to simple_spinlock powerpc/64s: implement queued

Updated with everybody's feedback (thanks all), and more performance results. What I've found is I might have been measuring the worst load point for the paravirt case, and by looking at a range of loads it's clear that queued spinlocks are overall better even on PV, doubly so when you look at the generally much improved worst case latencies. I have defaulted it to N even though