CC: kbuild-...@lists.01.org BCC: l...@intel.com CC: linux-ker...@vger.kernel.org TO: Vlastimil Babka <vba...@suse.cz> CC: Roman Gushchin <g...@fb.com> CC: Hyeonggon Yoo <42.hye...@gmail.com>
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: d615b5416f8a1afeb82d13b238f8152c572d59c0 commit: 401fb12c68c257b9c9116b1475c0ac26b646fcc0 mm/sl*b: Differentiate struct slab fields by sl*b implementations date: 4 months ago :::::: branch date: 9 hours ago :::::: commit date: 4 months ago compiler: nios2-linux-gcc (GCC) 11.2.0 reproduce (cppcheck warning): # apt-get install cppcheck git checkout 401fb12c68c257b9c9116b1475c0ac26b646fcc0 cppcheck --quiet --enable=style,performance,portability --template=gcc FILE If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <l...@intel.com> cppcheck possible warnings: (new ones prefixed by >>, may not real problems) mm/slob.c:146:57: warning: Parameter 'next' can be declared with const [constParameter] static void set_slob(slob_t *s, slobidx_t size, slob_t *next) ^ >> mm/slob.c:331:11: warning: Uninitialized variable: sp->units [uninitvar] if (sp->units < SLOB_UNITS(size)) ^ vim +331 mm/slob.c 10cef602950291 Matt Mackall 2006-01-08 297 95b35127f13661 Nicholas Piggin 2007-07-15 298 /* 95b35127f13661 Nicholas Piggin 2007-07-15 299 * slob_alloc: entry point into the slob allocator. 95b35127f13661 Nicholas Piggin 2007-07-15 300 */ 59bb47985c1db2 Vlastimil Babka 2019-10-06 301 static void *slob_alloc(size_t size, gfp_t gfp, int align, int node, 59bb47985c1db2 Vlastimil Babka 2019-10-06 302 int align_offset) 95b35127f13661 Nicholas Piggin 2007-07-15 303 { 50757018b4c9b0 Matthew Wilcox (Oracle 2021-10-04 304) struct folio *folio; 50757018b4c9b0 Matthew Wilcox (Oracle 2021-10-04 305) struct slab *sp; 20cecbae44528d Matt Mackall 2008-02-04 306 struct list_head *slob_list; 95b35127f13661 Nicholas Piggin 2007-07-15 307 slob_t *b = NULL; 95b35127f13661 Nicholas Piggin 2007-07-15 308 unsigned long flags; 130e8e09e2675b Tobin C. Harding 2019-05-13 309 bool _unused; 95b35127f13661 Nicholas Piggin 2007-07-15 310 20cecbae44528d Matt Mackall 2008-02-04 311 if (size < SLOB_BREAK1) 20cecbae44528d Matt Mackall 2008-02-04 312 slob_list = &free_slob_small; 20cecbae44528d Matt Mackall 2008-02-04 313 else if (size < SLOB_BREAK2) 20cecbae44528d Matt Mackall 2008-02-04 314 slob_list = &free_slob_medium; 20cecbae44528d Matt Mackall 2008-02-04 315 else 20cecbae44528d Matt Mackall 2008-02-04 316 slob_list = &free_slob_large; 20cecbae44528d Matt Mackall 2008-02-04 317 95b35127f13661 Nicholas Piggin 2007-07-15 318 spin_lock_irqsave(&slob_lock, flags); 95b35127f13661 Nicholas Piggin 2007-07-15 319 /* Iterate through each partially free page, try to find room */ adab7b68189d14 Tobin C. Harding 2019-05-13 320 list_for_each_entry(sp, slob_list, slab_list) { 130e8e09e2675b Tobin C. Harding 2019-05-13 321 bool page_removed_from_list = false; 6193a2ff180920 Paul Mundt 2007-07-15 322 #ifdef CONFIG_NUMA 6193a2ff180920 Paul Mundt 2007-07-15 323 /* 6193a2ff180920 Paul Mundt 2007-07-15 324 * If there's a node specification, search for a partial 6193a2ff180920 Paul Mundt 2007-07-15 325 * page with a matching node id in the freelist. 6193a2ff180920 Paul Mundt 2007-07-15 326 */ 50757018b4c9b0 Matthew Wilcox (Oracle 2021-10-04 327) if (node != NUMA_NO_NODE && slab_nid(sp) != node) 6193a2ff180920 Paul Mundt 2007-07-15 328 continue; 6193a2ff180920 Paul Mundt 2007-07-15 329 #endif d6269543ef24aa Matt Mackall 2007-07-21 330 /* Enough room on this page? */ d6269543ef24aa Matt Mackall 2007-07-21 @331 if (sp->units < SLOB_UNITS(size)) d6269543ef24aa Matt Mackall 2007-07-21 332 continue; 6193a2ff180920 Paul Mundt 2007-07-15 333 59bb47985c1db2 Vlastimil Babka 2019-10-06 334 b = slob_page_alloc(sp, size, align, align_offset, &page_removed_from_list); d6269543ef24aa Matt Mackall 2007-07-21 335 if (!b) d6269543ef24aa Matt Mackall 2007-07-21 336 continue; d6269543ef24aa Matt Mackall 2007-07-21 337 130e8e09e2675b Tobin C. Harding 2019-05-13 338 /* 130e8e09e2675b Tobin C. Harding 2019-05-13 339 * If slob_page_alloc() removed sp from the list then we 130e8e09e2675b Tobin C. Harding 2019-05-13 340 * cannot call list functions on sp. If so allocation 130e8e09e2675b Tobin C. Harding 2019-05-13 341 * did not fragment the page anyway so optimisation is 130e8e09e2675b Tobin C. Harding 2019-05-13 342 * unnecessary. 130e8e09e2675b Tobin C. Harding 2019-05-13 343 */ 130e8e09e2675b Tobin C. Harding 2019-05-13 344 if (!page_removed_from_list) { 130e8e09e2675b Tobin C. Harding 2019-05-13 345 /* 130e8e09e2675b Tobin C. Harding 2019-05-13 346 * Improve fragment distribution and reduce our average d6269543ef24aa Matt Mackall 2007-07-21 347 * search time by starting our next search here. (see 130e8e09e2675b Tobin C. Harding 2019-05-13 348 * Knuth vol 1, sec 2.5, pg 449) 130e8e09e2675b Tobin C. Harding 2019-05-13 349 */ adab7b68189d14 Tobin C. Harding 2019-05-13 350 if (!list_is_first(&sp->slab_list, slob_list)) adab7b68189d14 Tobin C. Harding 2019-05-13 351 list_rotate_to_front(&sp->slab_list, slob_list); 130e8e09e2675b Tobin C. Harding 2019-05-13 352 } 95b35127f13661 Nicholas Piggin 2007-07-15 353 break; 95b35127f13661 Nicholas Piggin 2007-07-15 354 } 95b35127f13661 Nicholas Piggin 2007-07-15 355 spin_unlock_irqrestore(&slob_lock, flags); 10cef602950291 Matt Mackall 2006-01-08 356 95b35127f13661 Nicholas Piggin 2007-07-15 357 /* Not enough space: must allocate a new page */ 95b35127f13661 Nicholas Piggin 2007-07-15 358 if (!b) { 6e9ed0cc4b963f Américo Wang 2009-01-19 359 b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node); 95b35127f13661 Nicholas Piggin 2007-07-15 360 if (!b) 6e9ed0cc4b963f Américo Wang 2009-01-19 361 return NULL; 50757018b4c9b0 Matthew Wilcox (Oracle 2021-10-04 362) folio = virt_to_folio(b); 50757018b4c9b0 Matthew Wilcox (Oracle 2021-10-04 363) __folio_set_slab(folio); 50757018b4c9b0 Matthew Wilcox (Oracle 2021-10-04 364) sp = folio_slab(folio); 10cef602950291 Matt Mackall 2006-01-08 365 10cef602950291 Matt Mackall 2006-01-08 366 spin_lock_irqsave(&slob_lock, flags); 95b35127f13661 Nicholas Piggin 2007-07-15 367 sp->units = SLOB_UNITS(PAGE_SIZE); b8c24c4aef94b1 Christoph Lameter 2012-06-13 368 sp->freelist = b; adab7b68189d14 Tobin C. Harding 2019-05-13 369 INIT_LIST_HEAD(&sp->slab_list); 95b35127f13661 Nicholas Piggin 2007-07-15 370 set_slob(b, SLOB_UNITS(PAGE_SIZE), b + SLOB_UNITS(PAGE_SIZE)); 20cecbae44528d Matt Mackall 2008-02-04 371 set_slob_page_free(sp, slob_list); 59bb47985c1db2 Vlastimil Babka 2019-10-06 372 b = slob_page_alloc(sp, size, align, align_offset, &_unused); 95b35127f13661 Nicholas Piggin 2007-07-15 373 BUG_ON(!b); 95b35127f13661 Nicholas Piggin 2007-07-15 374 spin_unlock_irqrestore(&slob_lock, flags); 10cef602950291 Matt Mackall 2006-01-08 375 } 9f88faee3ff7d6 Miles Chen 2017-11-15 376 if (unlikely(gfp & __GFP_ZERO)) d07dbea46405b3 Christoph Lameter 2007-07-17 377 memset(b, 0, size); 95b35127f13661 Nicholas Piggin 2007-07-15 378 return b; 10cef602950291 Matt Mackall 2006-01-08 379 } 10cef602950291 Matt Mackall 2006-01-08 380 :::::: The code at line 331 was first introduced by commit :::::: d6269543ef24aa012aa228c27af3adb074f7b36b slob: reduce list scanning :::::: TO: Matt Mackall <m...@selenic.com> :::::: CC: Linus Torvalds <torva...@woody.linux-foundation.org> -- 0-DAY CI Kernel Test Service https://01.org/lkp _______________________________________________ kbuild mailing list -- kbuild@lists.01.org To unsubscribe send an email to kbuild-le...@lists.01.org
