I am not sure how people are using partial object accounting. I believe it is used as a memory usage hint of slabs. On Mon, Mar 22, 2021 at 6:22 PM Vlastimil Babka <vbabka@xxxxxxx> wrote: > > On 3/22/21 2:46 AM, Shu Ming wrote: > > More precisely, ss will count partial objects like denty objects with > > "/sys/kernel/slab/dentry/partial" whose number can become huge. > > Uh, that's interesting. Would you know what exactly it uses the value for? I can > think of several reasons why it might be misleading. > > > On Thu, Mar 18, 2021 at 8:56 PM Xunlei Pang <xlpang@xxxxxxxxxxxxxxxxx> wrote: > >> > >> > >> > >> On 3/18/21 8:18 PM, Vlastimil Babka wrote: > >> > On 3/17/21 8:54 AM, Xunlei Pang wrote: > >> >> The node list_lock in count_partial() spends long time iterating > >> >> in case of large amount of partial page lists, which can cause > >> >> thunder herd effect to the list_lock contention. > >> >> > >> >> We have HSF RT(High-speed Service Framework Response-Time) monitors, > >> >> the RT figures fluctuated randomly, then we deployed a tool detecting > >> >> "irq off" and "preempt off" to dump the culprit's calltrace, capturing > >> >> the list_lock cost nearly 100ms with irq off issued by "ss", this also > >> >> caused network timeouts. > >> > > >> > I forgot to ask, how does "ss" come into this? It displays network connections > >> > AFAIK. Does it read any SLUB counters or slabinfo? > >> > > >> > >> ss may access /proc/slabinfo to acquire network related slab statistics. > > >
