Add single-bit test and iterator over set cids in an scx_cmask. v2: Bound scx_cmask_for_each_cid() to the active span. (sashiko AI)
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| @@ -225,4 +225,47 @@ static inline void __scx_cmask_set(u32 cid, struct scx_cmask *m) · 224 unmodified lines | ||
| 225 | 225 | *__scx_cmask_word(cid, m) |= BIT_U64(cid & 63); |
| 226 | 226 | } |
| 227 | 227 | |
| 228 | +/** | |
| 229 | + * scx_cmask_test - test whether @cid is set in @m | |
| 230 | + * @cid: cid to test | |
| 231 | + * @m: cmask to test | |
| 232 | + * | |
| 233 | + * Return %false if @cid is outside @m's active range. Otherwise return the | |
| 234 | + * bit's value. Read via READ_ONCE so callers can race set/clear writers. | |
| 235 | + */ | |
| 236 | +static inline bool scx_cmask_test(u32 cid, const struct scx_cmask *m) | |
| 237 | +{ | |
| 238 | + if (!__scx_cmask_contains(cid, m)) | |
| 239 | + return false; | |
| 240 | + return READ_ONCE(*__scx_cmask_word(cid, m)) & BIT_U64(cid & 63); | |
| 241 | +} | |
| 242 | + | |
| 243 | +/* | |
| 244 | + * Words of bits[] the active range spans, 0 if empty. Tighter than the storage | |
| 245 | + * SCX_CMASK_NR_WORDS() sizes for the worst-case base alignment. | |
| 246 | + */ | |
| 247 | +static inline u32 scx_cmask_nr_used_words(const struct scx_cmask *m) | |
| 248 | +{ | |
| 249 | + if (!m->nr_cids) | |
| 250 | + return 0; | |
| 251 | + return ((m->base & 63) + m->nr_cids - 1) / 64 + 1; | |
| 252 | +} | |
| 253 | + | |
| 254 | +/** | |
| 255 | + * scx_cmask_for_each_cid - iterate set cids in @m | |
| 256 | + * @cid: s32 loop var that receives each set cid in turn | |
| 257 | + * @m: cmask to iterate | |
| 258 | + * | |
| 259 | + * Visits set bits within @m's active range in ascending order. Scans only the | |
| 260 | + * words the active range spans, where head and tail padding is kept zero, so | |
| 261 | + * no per-cid range check is needed. | |
| 262 | + */ | |
| 263 | +#define scx_cmask_for_each_cid(cid, m) \ | |
| 264 | + for (u64 __bs = (m)->base & ~63u, __wi = 0, \ | |
| 265 | + __nw = scx_cmask_nr_used_words(m); \ | |
| 266 | + __wi < __nw; __wi++) \ | |
| 267 | + for (u64 __w = READ_ONCE((m)->bits[__wi]); \ | |
| 268 | + __w && ((cid) = __bs + __wi * 64 + __ffs64(__w), true); \ | |
| 269 | + __w &= __w - 1) | |
| 270 | + | |
| 228 | 271 | #endif /* _KERNEL_SCHED_EXT_CID_H */ |