On 2011.11.22 at 08:48 +0100, Eric Dumazet wrote: > Le lundi 21 novembre 2011 à 21:18 -0600, Christoph Lameter a écrit : > > > Hmmm... That means that c->page points to page not frozen. Per cpu > > partial pages are frozen until they are reused or until the partial list > > is flushed. > > > > Does this ever happen on x86 or only on other platforms? In put_cpu_partial() the > > this_cpu_cmpxchg really needs really to be irq safe. this_cpu_cmpxchg is > > only preempt safe. > > > > Index: linux-2.6/mm/slub.c > > =================================================================== > > --- linux-2.6.orig/mm/slub.c 2011-11-21 21:15:41.575673204 -0600 > > +++ linux-2.6/mm/slub.c 2011-11-21 21:16:33.442336849 -0600 > > @@ -1969,7 +1969,7 @@ > > page->pobjects = pobjects; > > page->next = oldpage; > > > > - } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); > > + } while (irqsafe_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); > > stat(s, CPU_PARTIAL_FREE); > > return pobjects; > > } > > > > For x86, I wonder if our !X86_FEATURE_CX16 support is correct on SMP > machines. > > this_cpu_cmpxchg16b_emu() claims to be IRQ safe, but may be buggy... > > Could we have somewhere a NMI handler calling kmalloc() ? > > Please Markus send us : > > cat /proc/cpuinfo processor : 0 vendor_id : AuthenticAMD cpu family : 16 model : 4 model name : AMD Phenom(tm) II X4 955 Processor stepping : 2 microcode : 0x10000c6 cpu MHz : 800.000 cache size : 512 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 4 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl nonstop_tsc extd_apicid pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt npt lbrv svm_lock nrip_save bogomips : 6420.59 TLB size : 1024 4K pages clflush size : 64 cache_alignment : 64 address sizes : 48 bits physical, 48 bits virtual power management: ts ttp tm stc 100mhzsteps hwpstate (*4) -- Markus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>