* [PATCH] inetpeer: use else if instead of if to reduce judgment @ 2021-02-26 10:57 Yejune Deng 2021-02-26 14:38 ` Eric Dumazet 0 siblings, 1 reply; 3+ messages in thread From: Yejune Deng @ 2021-02-26 10:57 UTC (permalink / raw) To: davem, yoshfuji, dsahern, kuba; +Cc: netdev, linux-kernel, yejune.deng In inet_initpeers(), if si.totalram <= (8192*1024)/PAGE_SIZE, it will be judged three times. Use else if instead of if, it only needs to be judged once. Signed-off-by: Yejune Deng <yejune.deng@gmail.com> --- net/ipv4/inetpeer.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index ff327a62c9ce..07cd1f8204b3 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -81,12 +81,12 @@ void __init inet_initpeers(void) * <kuznet@ms2.inr.ac.ru>. I don't have any opinion about the values * myself. --SAW */ - if (si.totalram <= (32768*1024)/PAGE_SIZE) + if (si.totalram <= (8192 * 1024) / PAGE_SIZE) + inet_peer_threshold >>= 4; /* about 128KB */ + else if (si.totalram <= (16384 * 1024) / PAGE_SIZE) + inet_peer_threshold >>= 2; /* about 512KB */ + else if (si.totalram <= (32768 * 1024) / PAGE_SIZE) inet_peer_threshold >>= 1; /* max pool size about 1MB on IA32 */ - if (si.totalram <= (16384*1024)/PAGE_SIZE) - inet_peer_threshold >>= 1; /* about 512KB */ - if (si.totalram <= (8192*1024)/PAGE_SIZE) - inet_peer_threshold >>= 2; /* about 128KB */ peer_cachep = kmem_cache_create("inet_peer_cache", sizeof(struct inet_peer), -- 2.29.0 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] inetpeer: use else if instead of if to reduce judgment 2021-02-26 10:57 [PATCH] inetpeer: use else if instead of if to reduce judgment Yejune Deng @ 2021-02-26 14:38 ` Eric Dumazet 2021-03-01 1:43 ` Yejune Deng 0 siblings, 1 reply; 3+ messages in thread From: Eric Dumazet @ 2021-02-26 14:38 UTC (permalink / raw) To: Yejune Deng, davem, yoshfuji, dsahern, kuba; +Cc: netdev, linux-kernel On 2/26/21 11:57 AM, Yejune Deng wrote: > In inet_initpeers(), if si.totalram <= (8192*1024)/PAGE_SIZE, it will > be judged three times. Use else if instead of if, it only needs to be > judged once. > > Signed-off-by: Yejune Deng <yejune.deng@gmail.com> > --- > net/ipv4/inetpeer.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c > index ff327a62c9ce..07cd1f8204b3 100644 > --- a/net/ipv4/inetpeer.c > +++ b/net/ipv4/inetpeer.c > @@ -81,12 +81,12 @@ void __init inet_initpeers(void) > * <kuznet@ms2.inr.ac.ru>. I don't have any opinion about the values > * myself. --SAW > */ > - if (si.totalram <= (32768*1024)/PAGE_SIZE) > + if (si.totalram <= (8192 * 1024) / PAGE_SIZE) > + inet_peer_threshold >>= 4; /* about 128KB */ > + else if (si.totalram <= (16384 * 1024) / PAGE_SIZE) > + inet_peer_threshold >>= 2; /* about 512KB */ > + else if (si.totalram <= (32768 * 1024) / PAGE_SIZE) > inet_peer_threshold >>= 1; /* max pool size about 1MB on IA32 */ If you really want to change this stuff, I would suggest updating comments, because nowadays, struct inet_peer on IA32 uses 128 bytes. So 32768 entries would consume 4 MB, 16384 entries would consume 2 MB and 4096 entries would consume 512KB Another idea would be to get rid of the cascade and use something that will not need to be adjusted in the future. diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index ff327a62c9ce9b1794104c3c924f5f2b9820ac8b..d5f486bd8c35234f99b22842e756a10531e070d6 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -65,7 +65,7 @@ EXPORT_SYMBOL_GPL(inet_peer_base_init); #define PEER_MAX_GC 32 /* Exported for sysctl_net_ipv4. */ -int inet_peer_threshold __read_mostly = 65536 + 128; /* start to throw entries more +int inet_peer_threshold __read_mostly; /* start to throw entries more * aggressively at this stage */ int inet_peer_minttl __read_mostly = 120 * HZ; /* TTL under high load: 120 sec */ int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min */ @@ -73,20 +73,13 @@ int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min /* Called from ip_output.c:ip_init */ void __init inet_initpeers(void) { - struct sysinfo si; + u64 nr_entries; - /* Use the straight interface to information about memory. */ - si_meminfo(&si); - /* The values below were suggested by Alexey Kuznetsov - * <kuznet@ms2.inr.ac.ru>. I don't have any opinion about the values - * myself. --SAW - */ - if (si.totalram <= (32768*1024)/PAGE_SIZE) - inet_peer_threshold >>= 1; /* max pool size about 1MB on IA32 */ - if (si.totalram <= (16384*1024)/PAGE_SIZE) - inet_peer_threshold >>= 1; /* about 512KB */ - if (si.totalram <= (8192*1024)/PAGE_SIZE) - inet_peer_threshold >>= 2; /* about 128KB */ + /* 1% of physical memory */ + nr_entries = div64_ul((u64)totalram_pages() << PAGE_SHIFT, + 100 * L1_CACHE_ALIGN(sizeof(struct inet_peer))); + + inet_peer_threshold = clamp_val(nr_entries, 4096, 65536 + 128); peer_cachep = kmem_cache_create("inet_peer_cache", sizeof(struct inet_peer), ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] inetpeer: use else if instead of if to reduce judgment 2021-02-26 14:38 ` Eric Dumazet @ 2021-03-01 1:43 ` Yejune Deng 0 siblings, 0 replies; 3+ messages in thread From: Yejune Deng @ 2021-03-01 1:43 UTC (permalink / raw) To: Eric Dumazet Cc: David Miller, yoshfuji, dsahern, Jakub Kicinski, netdev, Linux Kernel Mailing List Thanks，I will adopt it and resubmit. On Fri, Feb 26, 2021 at 10:50 PM Eric Dumazet <eric.dumazet@gmail.com> wrote: > > > > On 2/26/21 11:57 AM, Yejune Deng wrote: > > In inet_initpeers(), if si.totalram <= (8192*1024)/PAGE_SIZE, it will > > be judged three times. Use else if instead of if, it only needs to be > > judged once. > > > > Signed-off-by: Yejune Deng <yejune.deng@gmail.com> > > --- > > net/ipv4/inetpeer.c | 10 +++++----- > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c > > index ff327a62c9ce..07cd1f8204b3 100644 > > --- a/net/ipv4/inetpeer.c > > +++ b/net/ipv4/inetpeer.c > > @@ -81,12 +81,12 @@ void __init inet_initpeers(void) > > * <kuznet@ms2.inr.ac.ru>. I don't have any opinion about the values > > * myself. --SAW > > */ > > - if (si.totalram <= (32768*1024)/PAGE_SIZE) > > + if (si.totalram <= (8192 * 1024) / PAGE_SIZE) > > + inet_peer_threshold >>= 4; /* about 128KB */ > > + else if (si.totalram <= (16384 * 1024) / PAGE_SIZE) > > + inet_peer_threshold >>= 2; /* about 512KB */ > > + else if (si.totalram <= (32768 * 1024) / PAGE_SIZE) > > inet_peer_threshold >>= 1; /* max pool size about 1MB on IA32 */ > > > If you really want to change this stuff, I would suggest updating comments, > because nowadays, struct inet_peer on IA32 uses 128 bytes. > > So 32768 entries would consume 4 MB, > 16384 entries would consume 2 MB > > and 4096 entries would consume 512KB > > Another idea would be to get rid of the cascade and use something that > will not need to be adjusted in the future. > > diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c > index ff327a62c9ce9b1794104c3c924f5f2b9820ac8b..d5f486bd8c35234f99b22842e756a10531e070d6 100644 > --- a/net/ipv4/inetpeer.c > +++ b/net/ipv4/inetpeer.c > @@ -65,7 +65,7 @@ EXPORT_SYMBOL_GPL(inet_peer_base_init); > #define PEER_MAX_GC 32 > > /* Exported for sysctl_net_ipv4. */ > -int inet_peer_threshold __read_mostly = 65536 + 128; /* start to throw entries more > +int inet_peer_threshold __read_mostly; /* start to throw entries more > * aggressively at this stage */ > int inet_peer_minttl __read_mostly = 120 * HZ; /* TTL under high load: 120 sec */ > int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min */ > @@ -73,20 +73,13 @@ int inet_peer_maxttl __read_mostly = 10 * 60 * HZ; /* usual time to live: 10 min > /* Called from ip_output.c:ip_init */ > void __init inet_initpeers(void) > { > - struct sysinfo si; > + u64 nr_entries; > > - /* Use the straight interface to information about memory. */ > - si_meminfo(&si); > - /* The values below were suggested by Alexey Kuznetsov > - * <kuznet@ms2.inr.ac.ru>. I don't have any opinion about the values > - * myself. --SAW > - */ > - if (si.totalram <= (32768*1024)/PAGE_SIZE) > - inet_peer_threshold >>= 1; /* max pool size about 1MB on IA32 */ > - if (si.totalram <= (16384*1024)/PAGE_SIZE) > - inet_peer_threshold >>= 1; /* about 512KB */ > - if (si.totalram <= (8192*1024)/PAGE_SIZE) > - inet_peer_threshold >>= 2; /* about 128KB */ > + /* 1% of physical memory */ > + nr_entries = div64_ul((u64)totalram_pages() << PAGE_SHIFT, > + 100 * L1_CACHE_ALIGN(sizeof(struct inet_peer))); > + > + inet_peer_threshold = clamp_val(nr_entries, 4096, 65536 + 128); > > peer_cachep = kmem_cache_create("inet_peer_cache", > sizeof(struct inet_peer), > > > > > > ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-03-01 1:44 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-02-26 10:57 [PATCH] inetpeer: use else if instead of if to reduce judgment Yejune Deng 2021-02-26 14:38 ` Eric Dumazet 2021-03-01 1:43 ` Yejune Deng
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