search for: xbit_find_set

...w Wilcox wrote: > Here's the API I'm looking at right now. The user need take no lock; > the locking (spinlock) is handled internally to the implementation. I looked at the API some more and found some flaws: - how does xbit_alloc communicate back which bit it allocated? - What if xbit_find_set() is called on a completely empty array with a range of 0, ULONG_MAX -- there's no invalid number to return. - xbit_clear() can't return an error. Neither can xbit_zero(). - Need to add __must_check to various return values to discourage sloppy programming So I modify the proposed...

...w Wilcox wrote: > Here's the API I'm looking at right now. The user need take no lock; > the locking (spinlock) is handled internally to the implementation. I looked at the API some more and found some flaws: - how does xbit_alloc communicate back which bit it allocated? - What if xbit_find_set() is called on a completely empty array with a range of 0, ULONG_MAX -- there's no invalid number to return. - xbit_clear() can't return an error. Neither can xbit_zero(). - Need to add __must_check to various return values to discourage sloppy programming So I modify the proposed...

...ch seems conflict with the above "the user need take no lock". Doesn't the caller need a lock to avoid concurrent accesses to the ida bitmap? > I looked at the API some more and found some flaws: > - how does xbit_alloc communicate back which bit it allocated? > - What if xbit_find_set() is called on a completely empty array with > a range of 0, ULONG_MAX -- there's no invalid number to return. We'll change it to "bool xb_find_set(.., unsigned long *result)", returning false indicates no "1" bit is found. > - xbit_clear() can't return...

..._zero(struct xbitmap *, unsigned long start, unsigned long nbits); int xbit_fill(struct xbitmap *, unsigned long start, unsigned long nbits, gfp_t); unsigned long xbit_find_clear(struct xbitmap *, unsigned long start, unsigned long max); unsigned long xbit_find_set(struct xbitmap *, unsigned long start, unsigned long max); > static bool set_ulong(struct ulong_list_head *head, const unsigned long value) > { > if (!ptr) { > ptr = kzalloc(sizeof(*ptr), GFP_NOWAIT | __GFP_NOWARN); > if (!ptr) > goto out1; >...

...9;m proposing will take care of the locking for you. There's also no preallocation in the API. > We'll change it to "bool xb_find_set(.., unsigned long *result)", returning false indicates no "1" bit is found. I put a replacement proposal in the next paragraph: bool xbit_find_set(struct xbitmap *, unsigned long *start, unsigned long max); Maybe 'start' is the wrong name for that parameter. Let's call it 'bit'. It's both "where to start" and "first bit found". > > - xbit_clear() can't return an error. Neither can xbi...

...9;m proposing will take care of the locking for you. There's also no preallocation in the API. > We'll change it to "bool xb_find_set(.., unsigned long *result)", returning false indicates no "1" bit is found. I put a replacement proposal in the next paragraph: bool xbit_find_set(struct xbitmap *, unsigned long *start, unsigned long max); Maybe 'start' is the wrong name for that parameter. Let's call it 'bit'. It's both "where to start" and "first bit found". > > - xbit_clear() can't return an error. Neither can xbi...

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live