diff --git a/src/applet.c b/src/applet.c
index eafce3d1f..a6d7f43fd 100644
--- a/src/applet.c
+++ b/src/applet.c
@@ -48,7 +48,7 @@ int appctx_buf_available(void *arg)
 		return 0;
 
 	/* allocation possible now ? */
-	if (!b_alloc_margin(&si_ic(si)->buf, global.tune.reserved_bufs)) {
+	if (!b_alloc(&si_ic(si)->buf)) {
 		si_rx_buff_blk(si);
 		return 0;
 	}
diff --git a/src/check.c b/src/check.c
index c32e940c3..96276c140 100644
--- a/src/check.c
+++ b/src/check.c
@@ -994,12 +994,12 @@ int check_buf_available(void *target)
 {
 	struct check *check = target;
 
-	if ((check->state & CHK_ST_IN_ALLOC) && b_alloc_margin(&check->bi, 0)) {
+	if ((check->state & CHK_ST_IN_ALLOC) && b_alloc(&check->bi)) {
 		check->state &= ~CHK_ST_IN_ALLOC;
 		tasklet_wakeup(check->wait_list.tasklet);
 		return 1;
 	}
-	if ((check->state & CHK_ST_OUT_ALLOC) && b_alloc_margin(&check->bo, 0)) {
+	if ((check->state & CHK_ST_OUT_ALLOC) && b_alloc(&check->bo)) {
 		check->state &= ~CHK_ST_OUT_ALLOC;
 		tasklet_wakeup(check->wait_list.tasklet);
 		return 1;
@@ -1016,7 +1016,7 @@ struct buffer *check_get_buf(struct check *check, struct buffer *bptr)
 	struct buffer *buf = NULL;
 
 	if (likely(!LIST_ADDED(&check->buf_wait.list)) &&
-	    unlikely((buf = b_alloc_margin(bptr, 0)) == NULL)) {
+	    unlikely((buf = b_alloc(bptr)) == NULL)) {
 		check->buf_wait.target = check;
 		check->buf_wait.wakeup_cb = check_buf_available;
 		LIST_ADDQ(&ti->buffer_wq, &check->buf_wait.list);
diff --git a/src/flt_spoe.c b/src/flt_spoe.c
index 039747077..2d7b3b828 100644
--- a/src/flt_spoe.c
+++ b/src/flt_spoe.c
@@ -2837,7 +2837,7 @@ spoe_acquire_buffer(struct buffer *buf, struct buffer_wait *buffer_wait)
 	if (LIST_ADDED(&buffer_wait->list))
 		LIST_DEL_INIT(&buffer_wait->list);
 
-	if (b_alloc_margin(buf, global.tune.reserved_bufs))
+	if (b_alloc(buf))
 		return 1;
 
 	LIST_ADDQ(&ti->buffer_wq, &buffer_wait->list);
diff --git a/src/mux_fcgi.c b/src/mux_fcgi.c
index 48f11f27f..780d72172 100644
--- a/src/mux_fcgi.c
+++ b/src/mux_fcgi.c
@@ -570,14 +570,14 @@ static int fcgi_buf_available(void *target)
 	struct fcgi_conn *fconn = target;
 	struct fcgi_strm *fstrm;
 
-	if ((fconn->flags & FCGI_CF_DEM_DALLOC) && b_alloc_margin(&fconn->dbuf, 0)) {
+	if ((fconn->flags & FCGI_CF_DEM_DALLOC) && b_alloc(&fconn->dbuf)) {
 		TRACE_STATE("unblocking fconn, dbuf allocated", FCGI_EV_FCONN_RECV|FCGI_EV_FCONN_BLK|FCGI_EV_FCONN_WAKE, fconn->conn);
 		fconn->flags &= ~FCGI_CF_DEM_DALLOC;
 		fcgi_conn_restart_reading(fconn, 1);
 		return 1;
 	}
 
-	if ((fconn->flags & FCGI_CF_MUX_MALLOC) && b_alloc_margin(br_tail(fconn->mbuf), 0)) {
+	if ((fconn->flags & FCGI_CF_MUX_MALLOC) && b_alloc(br_tail(fconn->mbuf))) {
 		TRACE_STATE("unblocking fconn, mbuf allocated", FCGI_EV_FCONN_SEND|FCGI_EV_FCONN_BLK|FCGI_EV_FCONN_WAKE, fconn->conn);
 		fconn->flags &= ~FCGI_CF_MUX_MALLOC;
 		if (fconn->flags & FCGI_CF_DEM_MROOM) {
@@ -589,7 +589,7 @@ static int fcgi_buf_available(void *target)
 
 	if ((fconn->flags & FCGI_CF_DEM_SALLOC) &&
 	    (fstrm = fcgi_conn_st_by_id(fconn, fconn->dsi)) && fstrm->cs &&
-	    b_alloc_margin(&fstrm->rxbuf, 0)) {
+	    b_alloc(&fstrm->rxbuf)) {
 		TRACE_STATE("unblocking fstrm, rxbuf allocated", FCGI_EV_STRM_RECV|FCGI_EV_FSTRM_BLK|FCGI_EV_STRM_WAKE, fconn->conn, fstrm);
 		fconn->flags &= ~FCGI_CF_DEM_SALLOC;
 		fcgi_conn_restart_reading(fconn, 1);
@@ -605,7 +605,7 @@ static inline struct buffer *fcgi_get_buf(struct fcgi_conn *fconn, struct buffer
 	struct buffer *buf = NULL;
 
 	if (likely(!LIST_ADDED(&fconn->buf_wait.list)) &&
-	    unlikely((buf = b_alloc_margin(bptr, 0)) == NULL)) {
+	    unlikely((buf = b_alloc(bptr)) == NULL)) {
 		fconn->buf_wait.target = fconn;
 		fconn->buf_wait.wakeup_cb = fcgi_buf_available;
 		LIST_ADDQ(&ti->buffer_wq, &fconn->buf_wait.list);
diff --git a/src/mux_h1.c b/src/mux_h1.c
index 3c80e85f7..ca2e8a853 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -415,7 +415,7 @@ static int h1_buf_available(void *target)
 {
 	struct h1c *h1c = target;
 
-	if ((h1c->flags & H1C_F_IN_ALLOC) && b_alloc_margin(&h1c->ibuf, 0)) {
+	if ((h1c->flags & H1C_F_IN_ALLOC) && b_alloc(&h1c->ibuf)) {
 		TRACE_STATE("unblocking h1c, ibuf allocated", H1_EV_H1C_RECV|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1c->conn);
 		h1c->flags &= ~H1C_F_IN_ALLOC;
 		if (h1_recv_allowed(h1c))
@@ -423,7 +423,7 @@ static int h1_buf_available(void *target)
 		return 1;
 	}
 
-	if ((h1c->flags & H1C_F_OUT_ALLOC) && b_alloc_margin(&h1c->obuf, 0)) {
+	if ((h1c->flags & H1C_F_OUT_ALLOC) && b_alloc(&h1c->obuf)) {
 		TRACE_STATE("unblocking h1s, obuf allocated", H1_EV_TX_DATA|H1_EV_H1S_BLK|H1_EV_STRM_WAKE, h1c->conn, h1c->h1s);
 		h1c->flags &= ~H1C_F_OUT_ALLOC;
 		if (h1c->h1s)
@@ -431,7 +431,7 @@ static int h1_buf_available(void *target)
 		return 1;
 	}
 
-	if ((h1c->flags & H1C_F_IN_SALLOC) && h1c->h1s && b_alloc_margin(&h1c->h1s->rxbuf, 0)) {
+	if ((h1c->flags & H1C_F_IN_SALLOC) && h1c->h1s && b_alloc(&h1c->h1s->rxbuf)) {
 		TRACE_STATE("unblocking h1c, stream rxbuf allocated", H1_EV_H1C_RECV|H1_EV_H1C_BLK|H1_EV_H1C_WAKE, h1c->conn);
 		h1c->flags &= ~H1C_F_IN_SALLOC;
 		tasklet_wakeup(h1c->wait_event.tasklet);
@@ -449,7 +449,7 @@ static inline struct buffer *h1_get_buf(struct h1c *h1c, struct buffer *bptr)
 	struct buffer *buf = NULL;
 
 	if (likely(!LIST_ADDED(&h1c->buf_wait.list)) &&
-	    unlikely((buf = b_alloc_margin(bptr, 0)) == NULL)) {
+	    unlikely((buf = b_alloc(bptr)) == NULL)) {
 		h1c->buf_wait.target = h1c;
 		h1c->buf_wait.wakeup_cb = h1_buf_available;
 		LIST_ADDQ(&ti->buffer_wq, &h1c->buf_wait.list);
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 68b34621c..06abbc123 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -775,13 +775,13 @@ static int h2_buf_available(void *target)
 	struct h2c *h2c = target;
 	struct h2s *h2s;
 
-	if ((h2c->flags & H2_CF_DEM_DALLOC) && b_alloc_margin(&h2c->dbuf, 0)) {
+	if ((h2c->flags & H2_CF_DEM_DALLOC) && b_alloc(&h2c->dbuf)) {
 		h2c->flags &= ~H2_CF_DEM_DALLOC;
 		h2c_restart_reading(h2c, 1);
 		return 1;
 	}
 
-	if ((h2c->flags & H2_CF_MUX_MALLOC) && b_alloc_margin(br_tail(h2c->mbuf), 0)) {
+	if ((h2c->flags & H2_CF_MUX_MALLOC) && b_alloc(br_tail(h2c->mbuf))) {
 		h2c->flags &= ~H2_CF_MUX_MALLOC;
 
 		if (h2c->flags & H2_CF_DEM_MROOM) {
@@ -793,7 +793,7 @@ static int h2_buf_available(void *target)
 
 	if ((h2c->flags & H2_CF_DEM_SALLOC) &&
 	    (h2s = h2c_st_by_id(h2c, h2c->dsi)) && h2s->cs &&
-	    b_alloc_margin(&h2s->rxbuf, 0)) {
+	    b_alloc(&h2s->rxbuf)) {
 		h2c->flags &= ~H2_CF_DEM_SALLOC;
 		h2c_restart_reading(h2c, 1);
 		return 1;
@@ -807,7 +807,7 @@ static inline struct buffer *h2_get_buf(struct h2c *h2c, struct buffer *bptr)
 	struct buffer *buf = NULL;
 
 	if (likely(!LIST_ADDED(&h2c->buf_wait.list)) &&
-	    unlikely((buf = b_alloc_margin(bptr, 0)) == NULL)) {
+	    unlikely((buf = b_alloc(bptr)) == NULL)) {
 		h2c->buf_wait.target = h2c;
 		h2c->buf_wait.wakeup_cb = h2_buf_available;
 		LIST_ADDQ(&ti->buffer_wq, &h2c->buf_wait.list);
diff --git a/src/stream.c b/src/stream.c
index 54c6a77bf..b0c2bab37 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -329,10 +329,10 @@ int stream_buf_available(void *arg)
 	struct stream *s = arg;
 
 	if (!s->req.buf.size && !s->req.pipe && (s->si[0].flags & SI_FL_RXBLK_BUFF) &&
-	    b_alloc_margin(&s->req.buf, global.tune.reserved_bufs))
+	    b_alloc(&s->req.buf))
 		si_rx_buff_rdy(&s->si[0]);
 	else if (!s->res.buf.size && !s->res.pipe && (s->si[1].flags & SI_FL_RXBLK_BUFF) &&
-		 b_alloc_margin(&s->res.buf, 0))
+		 b_alloc(&s->res.buf))
 		si_rx_buff_rdy(&s->si[1]);
 	else
 		return 0;
@@ -772,7 +772,7 @@ static int stream_alloc_work_buffer(struct stream *s)
 	if (LIST_ADDED(&s->buffer_wait.list))
 		LIST_DEL_INIT(&s->buffer_wait.list);
 
-	if (b_alloc_margin(&s->res.buf, 0))
+	if (b_alloc(&s->res.buf))
 		return 1;
 
 	LIST_ADDQ(&ti->buffer_wq, &s->buffer_wait.list);