From: Christoph Hellwig <hch@lst.de>
Date: Tue, 5 Apr 2016 23:47:01 +0000 (+1000)
Subject: xfs: improve kmem_realloc
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=664b60f6babc98ee03c2ff15b9482cc8c5e15a83;p=linux-beck.git

xfs: improve kmem_realloc

Use krealloc to implement our realloc function.  This helps to avoid
new allocations if we are still in the slab bucket.  At least for the
bmap btree root that's actually the common case.

This also allows removing the now unused oldsize argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---

diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
index 686ba6fb20dd..339c696bbc01 100644
--- a/fs/xfs/kmem.c
+++ b/fs/xfs/kmem.c
@@ -93,19 +93,23 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
 }
 
 void *
-kmem_realloc(const void *ptr, size_t newsize, size_t oldsize,
-	     xfs_km_flags_t flags)
+kmem_realloc(const void *old, size_t newsize, xfs_km_flags_t flags)
 {
-	void	*new;
+	int	retries = 0;
+	gfp_t	lflags = kmem_flags_convert(flags);
+	void	*ptr;
 
-	new = kmem_alloc(newsize, flags);
-	if (ptr) {
-		if (new)
-			memcpy(new, ptr,
-				((oldsize < newsize) ? oldsize : newsize));
-		kmem_free(ptr);
-	}
-	return new;
+	do {
+		ptr = krealloc(old, newsize, lflags);
+		if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
+			return ptr;
+		if (!(++retries % 100))
+			xfs_err(NULL,
+	"%s(%u) possible memory allocation deadlock size %zu in %s (mode:0x%x)",
+				current->comm, current->pid,
+				newsize, __func__, lflags);
+		congestion_wait(BLK_RW_ASYNC, HZ/50);
+	} while (1);
 }
 
 void *
diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h
index d1c66e465ca5..689f746224e7 100644
--- a/fs/xfs/kmem.h
+++ b/fs/xfs/kmem.h
@@ -62,7 +62,7 @@ kmem_flags_convert(xfs_km_flags_t flags)
 
 extern void *kmem_alloc(size_t, xfs_km_flags_t);
 extern void *kmem_zalloc_large(size_t size, xfs_km_flags_t);
-extern void *kmem_realloc(const void *, size_t, size_t, xfs_km_flags_t);
+extern void *kmem_realloc(const void *, size_t, xfs_km_flags_t);
 static inline void  kmem_free(const void *ptr)
 {
 	kvfree(ptr);
diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 11faf7df14c8..1c842dce44b6 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -516,7 +516,6 @@ xfs_iroot_realloc(
 		new_max = cur_max + rec_diff;
 		new_size = XFS_BMAP_BROOT_SPACE_CALC(mp, new_max);
 		ifp->if_broot = kmem_realloc(ifp->if_broot, new_size,
-				XFS_BMAP_BROOT_SPACE_CALC(mp, cur_max),
 				KM_SLEEP | KM_NOFS);
 		op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
 						     ifp->if_broot_bytes);
@@ -660,7 +659,6 @@ xfs_idata_realloc(
 				ifp->if_u1.if_data =
 					kmem_realloc(ifp->if_u1.if_data,
 							real_size,
-							ifp->if_real_bytes,
 							KM_SLEEP | KM_NOFS);
 			}
 		} else {
@@ -1376,8 +1374,7 @@ xfs_iext_realloc_direct(
 		if (rnew_size != ifp->if_real_bytes) {
 			ifp->if_u1.if_extents =
 				kmem_realloc(ifp->if_u1.if_extents,
-						rnew_size,
-						ifp->if_real_bytes, KM_NOFS);
+						rnew_size, KM_NOFS);
 		}
 		if (rnew_size > ifp->if_real_bytes) {
 			memset(&ifp->if_u1.if_extents[ifp->if_bytes /
@@ -1461,9 +1458,8 @@ xfs_iext_realloc_indirect(
 	if (new_size == 0) {
 		xfs_iext_destroy(ifp);
 	} else {
-		ifp->if_u1.if_ext_irec = (xfs_ext_irec_t *)
-			kmem_realloc(ifp->if_u1.if_ext_irec,
-				new_size, size, KM_NOFS);
+		ifp->if_u1.if_ext_irec =
+			kmem_realloc(ifp->if_u1.if_ext_irec, new_size, KM_NOFS);
 	}
 }
 
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 396565f43247..bf6e80703613 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -3843,7 +3843,7 @@ xlog_recover_add_to_cont_trans(
 	old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
 	old_len = item->ri_buf[item->ri_cnt-1].i_len;
 
-	ptr = kmem_realloc(old_ptr, len+old_len, old_len, KM_SLEEP);
+	ptr = kmem_realloc(old_ptr, len + old_len, KM_SLEEP);
 	memcpy(&ptr[old_len], dp, len);
 	item->ri_buf[item->ri_cnt-1].i_len += len;
 	item->ri_buf[item->ri_cnt-1].i_addr = ptr;
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 536a0ee9cd5a..654799f716fc 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -89,7 +89,6 @@ xfs_uuid_mount(
 	if (hole < 0) {
 		xfs_uuid_table = kmem_realloc(xfs_uuid_table,
 			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
-			xfs_uuid_table_size  * sizeof(*xfs_uuid_table),
 			KM_SLEEP);
 		hole = xfs_uuid_table_size++;
 	}