litmus-rt.git - The LITMUS^RT kernel.

diff options

Diffstat (limited to 'fs/sysfs/inode.c')

-rw-r--r--

1 files changed, 6 insertions, 3 deletions

         if (!sd_iattr) {
                 /* setting attributes for the first time, allocate now */
-                sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL);
+                sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
                 if (!sd_iattr)
                         return -ENOMEM;
                 /* assign default attributes */
-                memset(sd_iattr, 0, sizeof(struct iattr));
                 sd_iattr->ia_mode = sd->s_mode;
                 sd_iattr->ia_uid = 0;
                 sd_iattr->ia_gid = 0;
 void sysfs_hash_and_remove(struct dentry * dir, const char * name)
 {
         struct sysfs_dirent * sd;
-        struct sysfs_dirent * parent_sd = dir->d_fsdata;
+        struct sysfs_dirent * parent_sd;
+        if (!dir)
+                return;
         if (dir->d_inode == NULL)
                 /* no inode means this hasn't been made visible yet */
                 return;
+        parent_sd = dir->d_fsdata;
         mutex_lock(&dir->d_inode->i_mutex);
         list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
                 if (!sd->s_element)

/* * TCP CUBIC: Binary Increase Congestion control for TCP v2.3 * Home page: * http://netsrv.csc.ncsu.edu/twiki/bin/view/Main/BIC * This is from the implementation of CUBIC TCP in * Sangtae Ha, Injong Rhee and Lisong Xu, * "CUBIC: A New TCP-Friendly High-Speed TCP Variant" * in ACM SIGOPS Operating System Review, July 2008. * Available from: * http://netsrv.csc.ncsu.edu/export/cubic_a_new_tcp_2008.pdf * * CUBIC integrates a new slow start algorithm, called HyStart. * The details of HyStart are presented in * Sangtae Ha and Injong Rhee, * "Taming the Elephants: New TCP Slow Start", NCSU TechReport 2008. * Available from: * http://netsrv.csc.ncsu.edu/export/hystart_techreport_2008.pdf * * All testing results are available from: * http://netsrv.csc.ncsu.edu/wiki/index.php/TCP_Testing * * Unless CUBIC is enabled and congestion window is large * this behaves the same as the original Reno. */ #include <linux/mm.h> #include <linux/module.h> #include <linux/math64.h> #include <net/tcp.h> #define BICTCP_BETA_SCALE 1024 /* Scale factor beta calculation * max_cwnd = snd_cwnd * beta */ #define BICTCP_HZ 10 /* BIC HZ 2^10 = 1024 */ /* Two methods of hybrid slow start */ #define HYSTART_ACK_TRAIN 0x1 #define HYSTART_DELAY 0x2 /* Number of delay samples for detecting the increase of delay */ #define HYSTART_MIN_SAMPLES 8 #define HYSTART_DELAY_MIN (4U<<3) #define HYSTART_DELAY_MAX (16U<<3) #define HYSTART_DELAY_THRESH(x) clamp(x, HYSTART_DELAY_MIN, HYSTART_DELAY_MAX) static int fast_convergence __read_mostly = 1; static int beta __read_mostly = 717; /* = 717/1024 (BICTCP_BETA_SCALE) */ static int initial_ssthresh __read_mostly; static int bic_scale __read_mostly = 41; static int tcp_friendliness __read_mostly = 1; static int hystart __read_mostly = 1; static int hystart_detect __read_mostly = HYSTART_ACK_TRAIN | HYSTART_DELAY; static int hystart_low_window __read_mostly = 16; static int hystart_ack_delta __read_mostly = 2; static u32 cube_rtt_scale __read_mostly; static u32 beta_scale __read_mostly; static u64 cube_factor __read_mostly; /* Note parameters that are used for precomputing scale factors are read-only */ module_param(fast_convergence, int, 0644); MODULE_PARM_DESC(fast_convergence, "turn on/off fast convergence"); module_param(beta, int, 0644); MODULE_PARM_DESC(beta, "beta for multiplicative increase"); module_param(initial_ssthresh, int, 0644); MODULE_PARM_DESC(initial_ssthresh, "initial value of slow start threshold"); module_param(bic_scale, int, 0444); MODULE_PARM_DESC(bic_scale, "scale (scaled by 1024) value for bic function (bic_scale/1024)"); module_param(tcp_friendliness, int, 0644); MODULE_PARM_DESC(tcp_friendliness, "turn on/off tcp friendliness"); module_param(hystart, int, 0644); MODULE_PARM_DESC(hystart, "turn on/off hybrid slow start algorithm"); module_param(hystart_detect, int, 0644); MODULE_PARM_DESC(hystart_detect, "hyrbrid slow start detection mechanisms" " 1: packet-train 2: delay 3: both packet-train and delay"); module_param(hystart_low_window, int, 0644); MODULE_PARM_DESC(hystart_low_window, "lower bound cwnd for hybrid slow start"); module_param(hystart_ack_delta, int, 0644); MODULE_PARM_DESC(hystart_ack_delta, "spacing between ack's indicating train (msecs)"); /* BIC TCP Parameters */ struct bictcp { u32 cnt; /* increase cwnd by 1 after ACKs */ u32 last_max_cwnd; /* last maximum snd_cwnd */ u32 loss_cwnd; /* congestion window at last loss */ u32 last_cwnd; /* the last snd_cwnd */ u32 last_time; /* time when updated last_cwnd */ u32 bic_origin_point;/* origin point of bic function */ u32 bic_K; /* time to origin point from the beginning of the current epoch */ u32 delay_min; /* min delay (msec << 3) */ u32 epoch_start; /* beginning of an epoch */ u32 ack_cnt; /* number of acks */ u32 tcp_cwnd; /* estimated tcp cwnd */ #define ACK_RATIO_SHIFT 4 #define ACK_RATIO_LIMIT (32u << ACK_RATIO_SHIFT) u16 delayed_ack; /* estimate the ratio of Packets/ACKs << 4 */ u8 sample_cnt; /* number of samples to decide curr_rtt */ u8 found; /* the exit point is found? */ u32 round_start; /* beginning of each round */ u32 end_seq; /* end_seq of the round */ u32 last_ack; /* last time when the ACK spacing is close */ u32 curr_rtt; /* the minimum rtt of current round */ }; static inline void bictcp_reset(struct bictcp *ca) { ca->cnt = 0; ca->last_max_cwnd = 0; ca->loss_cwnd = 0; ca->last_cwnd = 0; ca->last_time = 0; ca->bic_origin_point = 0; ca->bic_K = 0; ca->delay_min = 0; ca->epoch_start = 0; ca->delayed_ack = 2 << ACK_RATIO_SHIFT; ca->ack_cnt = 0; ca->tcp_cwnd = 0; ca->found = 0; } static inline u32 bictcp_clock(void) { #if HZ < 1000 return ktime_to_ms(ktime_get_real()); #else return jiffies_to_msecs(jiffies); #endif } static inline void bictcp_hystart_reset(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct bictcp *ca = inet_csk_ca(sk); ca->round_start = ca->last_ack = bictcp_clock(); ca->end_seq = tp->snd_nxt; ca->curr_rtt = 0; ca->sample_cnt = 0; } static void bictcp_init(struct sock *sk) { bictcp_reset(inet_csk_ca(sk)); if (hystart) bictcp_hystart_reset(sk); if (!hystart && initial_ssthresh) tcp_sk(sk)->snd_ssthresh = initial_ssthresh; } /* calculate the cubic root of x using a table lookup followed by one * Newton-Raphson iteration. * Avg err ~= 0.195% */ static u32 cubic_root(u64 a) { u32 x, b, shift; /* * cbrt(x) MSB values for x MSB values in [0..63]. * Precomputed then refined by hand - Willy Tarreau * * For x in [0..63], * v = cbrt(x << 18) - 1 * cbrt(x) = (v[x] + 10) >> 6 */ static const u8 v[] = { /* 0x00 */ 0, 54, 54, 54, 118, 118, 118, 118, /* 0x08 */ 123, 129, 134, 138, 143, 147, 151, 156, /* 0x10 */ 157, 161, 164, 168, 170, 173, 176, 179, /* 0x18 */ 181, 185, 187, 190, 192, 194, 197, 199, /* 0x20 */ 200, 202, 204, 206, 209, 211, 213, 215, /* 0x28 */ 217, 219, 221, 222, 224, 225, 227, 229, /* 0x30 */ 231, 232, 234, 236, 237, 239, 240, 242, /* 0x38 */ 244, 245, 246, 248, 250, 251, 252, 254, }; b = fls64(a); if (b < 7) { /* a in [0..63] */ return ((u32)v[(u32)a] + 35) >> 6; } b = ((b * 84) >> 8) - 1; shift = (a >> (b * 3)); x = ((u32)(((u32)v[shift] + 10) << b)) >> 6; /* * Newton-Raphson iteration * 2 * x = ( 2 * x + a / x ) / 3 * k+1 k k */ x = (2 * x + (u32)div64_u64(a, (u64)x * (u64)(x - 1))); x = ((x * 341) >> 10); return x; } /* * Compute congestion window to use. */ static inline void bictcp_update(struct bictcp *ca, u32 cwnd) { u64 offs; u32 delta, t, bic_target, max_cnt; ca->ack_cnt++; /* count the number of ACKs */ if (ca->last_cwnd == cwnd && (s32)(tcp_time_stamp - ca->last_time) <= HZ / 32) return; ca->last_cwnd = cwnd; ca->last_time = tcp_time_stamp; if (ca->epoch_start == 0) { ca->epoch_start = tcp_time_stamp; /* record the beginning of an epoch */ ca->ack_cnt = 1; /* start counting */ ca->tcp_cwnd = cwnd; /* syn with cubic */ if (ca->last_max_cwnd <= cwnd) { ca->bic_K = 0; ca->bic_origin_point = cwnd; } else { /* Compute new K based on * (wmax-cwnd) * (srtt>>3 / HZ) / c * 2^(3*bictcp_HZ) */ ca->bic_K = cubic_root(cube_factor * (ca->last_max_cwnd - cwnd)); ca->bic_origin_point = ca->last_max_cwnd; } } /* cubic function - calc*/ /* calculate c * time^3 / rtt, * while considering overflow in calculation of time^3 * (so time^3 is done by using 64 bit) * and without the support of division of 64bit numbers * (so all divisions are done by using 32 bit) * also NOTE the unit of those veriables * time = (t - K) / 2^bictcp_HZ * c = bic_scale >> 10 * rtt = (srtt >> 3) / HZ * !!! The following code does not have overflow problems, * if the cwnd < 1 million packets !!! */ /* change the unit from HZ to bictcp_HZ */ t = ((tcp_time_stamp + msecs_to_jiffies(ca->delay_min>>3) - ca->epoch_start) << BICTCP_HZ) / HZ; if (t < ca->bic_K) /* t - K */ offs = ca->bic_K - t; else offs = t - ca->bic_K; /* c/rtt * (t-K)^3 */ delta = (cube_rtt_scale * offs * offs * offs) >> (10+3*BICTCP_HZ); if (t < ca->bic_K) /* below origin*/ bic_target = ca->bic_origin_point - delta; else /* above origin*/ bic_target = ca->bic_origin_point + delta; /* cubic function - calc bictcp_cnt*/ if (bic_target > cwnd) { ca->cnt = cwnd / (bic_target - cwnd); } else { ca->cnt = 100 * cwnd; /* very small increment*/ } /* * The initial growth of cubic function may be too conservative * when the available bandwidth is still unknown. */ if (ca->loss_cwnd == 0 && ca->cnt > 20) ca->cnt = 20; /* increase cwnd 5% per RTT */ /* TCP Friendly */ if (tcp_friendliness) { u32 scale = beta_scale; delta = (cwnd * scale) >> 3; while (ca->ack_cnt > delta) { /* update tcp cwnd */ ca->ack_cnt -= delta; ca->tcp_cwnd++; } if (ca->tcp_cwnd > cwnd){ /* if bic is slower than tcp */ delta = ca->tcp_cwnd - cwnd; max_cnt = cwnd / delta; if (ca->cnt > max_cnt) ca->cnt = max_cnt; } } ca->cnt = (ca->cnt << ACK_RATIO_SHIFT) / ca->delayed_ack; if (ca->cnt == 0) /* cannot be zero */ ca->cnt = 1; } static void bictcp_cong_avoid(struct sock *sk, u32 ack, u32 in_flight) { struct tcp_sock *tp = tcp_sk(sk); struct bictcp *ca = inet_csk_ca(sk); if (!tcp_is_cwnd_limited(sk, in_flight)) return; if (tp->snd_cwnd <= tp->snd_ssthresh) { if (hystart && after(ack, ca->end_seq)) bictcp_hystart_reset(sk); tcp_slow_start(tp); } else { bictcp_update(ca, tp->snd_cwnd); tcp_cong_avoid_ai(tp, ca->cnt); } } static u32 bictcp_recalc_ssthresh(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); struct bictcp *ca = inet_csk_ca(sk); ca->epoch_start = 0; /* end of epoch */ /* Wmax and fast convergence */ if (tp->snd_cwnd < ca->last_max_cwnd && fast_convergence)


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