#ifndef HASH_H #define HASH_H /* Hash table implementation from the GIT project. */ /* Copyright 2008 (C) Linus Torvalds, GPL version 2 */ /* * These are some simple generic hash table helper functions. * Not necessarily suitable for all users, but good for things * where you want to just keep track of a list of things, and * have a good hash to use on them. * * It keeps the hash table at roughly 50-75% free, so the memory * cost of the hash table itself is roughly * * 3 * 2*sizeof(void *) * nr_of_objects * * bytes. * * FIXME: on 64-bit architectures, we waste memory. It would be * good to have just 32-bit pointers, requiring a special allocator * for hashed entries or something. */ #include #define alloc_nr(x) (((x) + 16) * 3 / 2) #define INSERT_HASH_PROTOS(ops, table) \ do { \ void **pos = insert_hash((ops).key, &(ops), &(table)); \ /* We already had an entry there? */ \ if (pos) { \ (ops).next = *pos; \ *pos = &(ops); \ } \ } while (0) struct hash_table_entry { unsigned int hash; void *ptr; }; struct hash_table { unsigned int size, nr; struct hash_table_entry *array; }; extern void *lookup_hash(unsigned int hash, const struct hash_table *table); extern void **insert_hash(unsigned int hash, void *ptr, struct hash_table *table); extern void *remove_hash(unsigned int hash, void *ptr, void *ptr_next, struct hash_table *table); extern int for_each_hash(const struct hash_table *table, int (*fn)(void *)); extern int for_each_hash_int(const struct hash_table *table, int (*fn)(void *, int), int arg); extern void free_hash(struct hash_table *table); static inline void init_hash(struct hash_table *table) { table->size = 0; table->nr = 0; table->array = NULL; } static inline unsigned char icase_hash(unsigned char c) { return c & ~((c & 0x40) >> 1); } static inline unsigned int hash_name(const char *name, int namelen) { unsigned int hash = 0x123; do { unsigned char c = *name++; c = icase_hash(c); hash = hash * 101 + c; } while (--namelen); return hash; } #endif /* HASH_H */ numa?h=nds-private-remove&id=efd1535270c1deb0487527bf0c3c827301a69c93'>commitdiff
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authorBob Liu <bob.liu@oracle.com>2016-06-07 10:43:15 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2016-06-08 13:54:39 -0400
commitefd1535270c1deb0487527bf0c3c827301a69c93 (patch)
treee0afb0ad9d8e7db1ed1d52ba4c07e2278ff2b7c4 /Documentation/vm/numa
parent116f7d4a21fe450efc652c4850eb27cda36c9db0 (diff)
xen-blkfront: don't call talk_to_blkback when already connected to blkback
Sometimes blkfront may twice receive blkback_changed() notification (XenbusStateConnected) after migration, which will cause talk_to_blkback() to be called twice too and confuse xen-blkback. The flow is as follow: blkfront blkback blkfront_resume() > talk_to_blkback() > Set blkfront to XenbusStateInitialised front changed() > Connect() > Set blkback to XenbusStateConnected blkback_changed() > Skip talk_to_blkback() because frontstate == XenbusStateInitialised > blkfront_connect() > Set blkfront to XenbusStateConnected ----- And here we get another XenbusStateConnected notification leading to: ----- blkback_changed() > because now frontstate != XenbusStateInitialised talk_to_blkback() is also called again > blkfront state changed from XenbusStateConnected to XenbusStateInitialised (Which is not correct!) front_changed(): > Do nothing because blkback already in XenbusStateConnected Now blkback is in XenbusStateConnected but blkfront is still in XenbusStateInitialised - leading to no disks. Poking of the XenbusStateConnected state is allowed (to deal with block disk change) and has to be dealt with. The most likely cause of this bug are custom udev scripts hooking up the disks and then validating the size. Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'Documentation/vm/numa')