Hi Arun, Thank you for the patch! Yet something to improve: [auto build test ERROR on linus/master] [also build test ERROR on v4.20-rc1 next-20181107] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Arun-KS/mm-Fix-multiple-evaluvations-of-totalram_pages-and-managed_pages/20181108-025657 config: x86_64-randconfig-x018-201844 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 All error/warnings (new ones prefixed by >>): In file included from include/asm-generic/bug.h:5:0, from arch/x86/include/asm/bug.h:47, from include/linux/bug.h:5, from include/linux/mmdebug.h:5, from include/linux/gfp.h:5, from mm/kasan/quarantine.c:20: mm/kasan/quarantine.c: In function 'quarantine_reduce': >> include/linux/compiler.h:246:20: error: lvalue required as unary '&' operand __read_once_size(&(x), __u.__c, sizeof(x)); \ ^ >> include/linux/compiler.h:252:22: note: in expansion of macro '__READ_ONCE' #define READ_ONCE(x) __READ_ONCE(x, 1) ^~~~~~~~~~~ >> mm/kasan/quarantine.c:239:16: note: in expansion of macro 'READ_ONCE' total_size = (READ_ONCE(totalram_pages()) << PAGE_SHIFT) / ^~~~~~~~~ include/linux/compiler.h:248:28: error: lvalue required as unary '&' operand __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ ^ >> include/linux/compiler.h:252:22: note: in expansion of macro '__READ_ONCE' #define READ_ONCE(x) __READ_ONCE(x, 1) ^~~~~~~~~~~ >> mm/kasan/quarantine.c:239:16: note: in expansion of macro 'READ_ONCE' total_size = (READ_ONCE(totalram_pages()) << PAGE_SHIFT) / ^~~~~~~~~ -- In file included from include/asm-generic/bug.h:5:0, from arch/x86/include/asm/bug.h:47, from include/linux/bug.h:5, from include/linux/mmdebug.h:5, from include/linux/gfp.h:5, from mm//kasan/quarantine.c:20: mm//kasan/quarantine.c: In function 'quarantine_reduce': >> include/linux/compiler.h:246:20: error: lvalue required as unary '&' operand __read_once_size(&(x), __u.__c, sizeof(x)); \ ^ >> include/linux/compiler.h:252:22: note: in expansion of macro '__READ_ONCE' #define READ_ONCE(x) __READ_ONCE(x, 1) ^~~~~~~~~~~ mm//kasan/quarantine.c:239:16: note: in expansion of macro 'READ_ONCE' total_size = (READ_ONCE(totalram_pages()) << PAGE_SHIFT) / ^~~~~~~~~ include/linux/compiler.h:248:28: error: lvalue required as unary '&' operand __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ ^ >> include/linux/compiler.h:252:22: note: in expansion of macro '__READ_ONCE' #define READ_ONCE(x) __READ_ONCE(x, 1) ^~~~~~~~~~~ mm//kasan/quarantine.c:239:16: note: in expansion of macro 'READ_ONCE' total_size = (READ_ONCE(totalram_pages()) << PAGE_SHIFT) / ^~~~~~~~~ vim +/READ_ONCE +239 mm/kasan/quarantine.c 211 212 void quarantine_reduce(void) 213 { 214 size_t total_size, new_quarantine_size, percpu_quarantines; 215 unsigned long flags; 216 int srcu_idx; 217 struct qlist_head to_free = QLIST_INIT; 218 219 if (likely(READ_ONCE(quarantine_size) <= 220 READ_ONCE(quarantine_max_size))) 221 return; 222 223 /* 224 * srcu critical section ensures that quarantine_remove_cache() 225 * will not miss objects belonging to the cache while they are in our 226 * local to_free list. srcu is chosen because (1) it gives us private 227 * grace period domain that does not interfere with anything else, 228 * and (2) it allows synchronize_srcu() to return without waiting 229 * if there are no pending read critical sections (which is the 230 * expected case). 231 */ 232 srcu_idx = srcu_read_lock(&remove_cache_srcu); 233 raw_spin_lock_irqsave(&quarantine_lock, flags); 234 235 /* 236 * Update quarantine size in case of hotplug. Allocate a fraction of 237 * the installed memory to quarantine minus per-cpu queue limits. 238 */ > 239 total_size = (READ_ONCE(totalram_pages()) << PAGE_SHIFT) / 240 QUARANTINE_FRACTION; 241 percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus(); 242 new_quarantine_size = (total_size < percpu_quarantines) ? 243 0 : total_size - percpu_quarantines; 244 WRITE_ONCE(quarantine_max_size, new_quarantine_size); 245 /* Aim at consuming at most 1/2 of slots in quarantine. */ 246 WRITE_ONCE(quarantine_batch_size, max((size_t)QUARANTINE_PERCPU_SIZE, 247 2 * total_size / QUARANTINE_BATCHES)); 248 249 if (likely(quarantine_size > quarantine_max_size)) { 250 qlist_move_all(&global_quarantine[quarantine_head], &to_free); 251 WRITE_ONCE(quarantine_size, quarantine_size - to_free.bytes); 252 quarantine_head++; 253 if (quarantine_head == QUARANTINE_BATCHES) 254 quarantine_head = 0; 255 } 256 257 raw_spin_unlock_irqrestore(&quarantine_lock, flags); 258 259 qlist_free_all(&to_free, NULL); 260 srcu_read_unlock(&remove_cache_srcu, srcu_idx); 261 } 262 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation