| Message ID | 20220808062601.836025-10-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/demotion: Memory tiers and demotion | expand |
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes: > The most common case for certain node_random usage (demotion nodemask) is with > nodemask weight 1. We can avoid calling get_random_init() in that case and > always return the only node set in the nodemask. I think that this patch can sit between [5/9] and [6/9], just after it is used. > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > --- > lib/nodemask.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/lib/nodemask.c b/lib/nodemask.c > index e22647f5181b..c91a6b0404a5 100644 > --- a/lib/nodemask.c > +++ b/lib/nodemask.c > @@ -20,12 +20,21 @@ EXPORT_SYMBOL(__next_node_in); > */ > int node_random(const nodemask_t *maskp) > { > - int w, bit = NUMA_NO_NODE; > + int w, bit; > > w = nodes_weight(*maskp); > - if (w) > + switch (w) { > + case 0: > + bit = NUMA_NO_NODE; > + break; > + case 1: > + bit = __first_node(maskp); Per my understanding, first_node() is the formal API and we should use that? Just like we use nodes_weight() instead of __nodes_weight(). Best Regards, Huang, Ying > + break; > + default: > bit = bitmap_ord_to_pos(maskp->bits, > - get_random_int() % w, MAX_NUMNODES); > + get_random_int() % w, MAX_NUMNODES); > + break; > + } > return bit; > } > #endif
On 8/9/22 8:43 AM, Huang, Ying wrote: > "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes: > >> The most common case for certain node_random usage (demotion nodemask) is with >> nodemask weight 1. We can avoid calling get_random_init() in that case and >> always return the only node set in the nodemask. > > I think that this patch can sit between [5/9] and [6/9], just after it > is used. > >> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> >> --- >> lib/nodemask.c | 15 ++++++++++++--- >> 1 file changed, 12 insertions(+), 3 deletions(-) >> >> diff --git a/lib/nodemask.c b/lib/nodemask.c >> index e22647f5181b..c91a6b0404a5 100644 >> --- a/lib/nodemask.c >> +++ b/lib/nodemask.c >> @@ -20,12 +20,21 @@ EXPORT_SYMBOL(__next_node_in); >> */ >> int node_random(const nodemask_t *maskp) >> { >> - int w, bit = NUMA_NO_NODE; >> + int w, bit; >> >> w = nodes_weight(*maskp); >> - if (w) >> + switch (w) { >> + case 0: >> + bit = NUMA_NO_NODE; >> + break; >> + case 1: >> + bit = __first_node(maskp); > > Per my understanding, first_node() is the formal API and we should use > that? Just like we use nodes_weight() instead of __nodes_weight(). > updated. -aneesh
diff --git a/lib/nodemask.c b/lib/nodemask.c index e22647f5181b..c91a6b0404a5 100644 --- a/lib/nodemask.c +++ b/lib/nodemask.c @@ -20,12 +20,21 @@ EXPORT_SYMBOL(__next_node_in); */ int node_random(const nodemask_t *maskp) { - int w, bit = NUMA_NO_NODE; + int w, bit; w = nodes_weight(*maskp); - if (w) + switch (w) { + case 0: + bit = NUMA_NO_NODE; + break; + case 1: + bit = __first_node(maskp); + break; + default: bit = bitmap_ord_to_pos(maskp->bits, - get_random_int() % w, MAX_NUMNODES); + get_random_int() % w, MAX_NUMNODES); + break; + } return bit; } #endif
The most common case for certain node_random usage (demotion nodemask) is with nodemask weight 1. We can avoid calling get_random_init() in that case and always return the only node set in the nodemask. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- lib/nodemask.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)