Attachment 834840 Details for Bug 850426 – Another variant that adds a syscall to do readahead on the relevant blocks

[patch] Another variant that adds a syscall to do readahead on the relevant blocks

readahead-try-02.patch (text/plain), 13.66 KB, created by Abhijith Das on 2013-12-10 15:57:35 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Abhijith Das

Created: 2013-12-10 15:57:35 UTC

Size: 13.66 KB

patch

obsolete

>diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl
>index aabfb83..3b75649 100644
>--- a/arch/x86/syscalls/syscall_32.tbl
>+++ b/arch/x86/syscalls/syscall_32.tbl
>@@ -357,3 +357,4 @@
> 348	i386	process_vm_writev	sys_process_vm_writev		compat_sys_process_vm_writev
> 349	i386	kcmp			sys_kcmp
> 350	i386	finit_module		sys_finit_module
>+351	i386	rddir_readahead		sys_rddir_readahead
>diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
>index 38ae65d..2ede45e 100644
>--- a/arch/x86/syscalls/syscall_64.tbl
>+++ b/arch/x86/syscalls/syscall_64.tbl
>@@ -320,6 +320,7 @@
> 311	64	process_vm_writev	sys_process_vm_writev
> 312	common	kcmp			sys_kcmp
> 313	common	finit_module		sys_finit_module
>+314	common	rddir_readahead		sys_rddir_readahead
> 
> #
> # x32-specific system call numbers start at 512 to avoid cache impact
>diff --git a/fs/gfs2/Makefile b/fs/gfs2/Makefile
>index 8612820..b1e4490 100644
>--- a/fs/gfs2/Makefile
>+++ b/fs/gfs2/Makefile
>@@ -4,7 +4,8 @@ gfs2-y := acl.o bmap.o dir.o xattr.o glock.o \
> 	glops.o log.o lops.o main.o meta_io.o \
> 	aops.o dentry.o export.o file.o \
> 	ops_fstype.o inode.o quota.o \
>-	recovery.o rgrp.o super.o sys.o trans.o util.o
>+	recovery.o rgrp.o super.o sys.o trans.o \
>+	rddir_ra.o util.o
> 
> gfs2-$(CONFIG_GFS2_FS_LOCKING_DLM) += lock_dlm.o
> 
>diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
>index 2e5fc26..4481b95 100644
>--- a/fs/gfs2/dir.c
>+++ b/fs/gfs2/dir.c
>@@ -1227,6 +1227,7 @@ static int compare_dents(const void *a, const void *b)
>  */
> 
> static int do_filldir_main(struct gfs2_inode *dip, struct dir_context *ctx,
>+			   struct gfs2_rddir_ra *rra,
> 			   const struct gfs2_dirent **darr, u32 entries,
> 			   int *copied)
> {
>@@ -1266,11 +1267,18 @@ static int do_filldir_main(struct gfs2_inode *dip, struct dir_context *ctx,
> 			ctx->pos = off;
> 		}
> 
>-		if (!dir_emit(ctx, (const char *)(dent + 1),
>-				be16_to_cpu(dent->de_name_len),
>-				be64_to_cpu(dent->de_inum.no_addr),
>-				be16_to_cpu(dent->de_type)))
>-			return 1;
>+		if (!rra) {
>+			if (!dir_emit(ctx, (const char *)(dent + 1),
>+				      be16_to_cpu(dent->de_name_len),
>+				      be64_to_cpu(dent->de_inum.no_addr),
>+				      be16_to_cpu(dent->de_type)))
>+				return 1;
>+		} else { /* we were called by rddir_ra syscall */
>+			if (collect_inode_blocks(rra,
>+						 be64_to_cpu(dent->de_inum.no_addr),
>+						 be16_to_cpu(dent->de_type)))
>+				return 1;
>+		}
> 
> 		*copied = 1;
> 	}
>@@ -1304,8 +1312,8 @@ static void gfs2_free_sort_buffer(void *ptr)
> }
> 
> static int gfs2_dir_read_leaf(struct inode *inode, struct dir_context *ctx,
>-			      int *copied, unsigned *depth,
>-			      u64 leaf_no)
>+			      struct gfs2_rddir_ra *rra, int *copied,
>+			      unsigned *depth, u64 leaf_no)
> {
> 	struct gfs2_inode *ip = GFS2_I(inode);
> 	struct gfs2_sbd *sdp = GFS2_SB(inode);
>@@ -1382,7 +1390,7 @@ static int gfs2_dir_read_leaf(struct inode *inode, struct dir_context *ctx,
> 	} while(lfn);
> 
> 	BUG_ON(entries2 != entries);
>-	error = do_filldir_main(ip, ctx, darr, entries, copied);
>+	error = do_filldir_main(ip, ctx, rra, darr, entries, copied);
> out_free:
> 	for(i = 0; i < leaf; i++)
> 		brelse(larr[i]);
>@@ -1447,7 +1455,7 @@ static void gfs2_dir_readahead(struct inode *inode, unsigned hsize, u32 index,
>  */
> 
> static int dir_e_read(struct inode *inode, struct dir_context *ctx,
>-		      struct file_ra_state *f_ra)
>+		      struct gfs2_rddir_ra *rra, struct file_ra_state *f_ra)
> {
> 	struct gfs2_inode *dip = GFS2_I(inode);
> 	u32 hsize, len = 0;
>@@ -1470,7 +1478,7 @@ static int dir_e_read(struct inode *inode, struct dir_context *ctx,
> 	gfs2_dir_readahead(inode, hsize, index, f_ra);
> 
> 	while (index < hsize) {
>-		error = gfs2_dir_read_leaf(inode, ctx,
>+		error = gfs2_dir_read_leaf(inode, ctx, rra,
> 					   &copied, &depth,
> 					   be64_to_cpu(lp[index]));
> 		if (error)
>@@ -1486,7 +1494,7 @@ static int dir_e_read(struct inode *inode, struct dir_context *ctx,
> }
> 
> int gfs2_dir_read(struct inode *inode, struct dir_context *ctx,
>-		  struct file_ra_state *f_ra)
>+		  struct gfs2_rddir_ra *rra, struct file_ra_state *f_ra)
> {
> 	struct gfs2_inode *dip = GFS2_I(inode);
> 	struct gfs2_sbd *sdp = GFS2_SB(inode);
>@@ -1500,7 +1508,7 @@ int gfs2_dir_read(struct inode *inode, struct dir_context *ctx,
> 		return 0;
> 
> 	if (dip->i_diskflags & GFS2_DIF_EXHASH)
>-		return dir_e_read(inode, ctx, f_ra);
>+		return dir_e_read(inode, ctx, rra, f_ra);
> 
> 	if (!gfs2_is_stuffed(dip)) {
> 		gfs2_consist_inode(dip);
>@@ -1532,7 +1540,7 @@ int gfs2_dir_read(struct inode *inode, struct dir_context *ctx,
> 			error = -EIO;
> 			goto out;
> 		}
>-		error = do_filldir_main(dip, ctx, darr,
>+		error = do_filldir_main(dip, ctx, rra, darr,
> 					dip->i_entries, &copied);
> out:
> 		kfree(darr);
>diff --git a/fs/gfs2/dir.h b/fs/gfs2/dir.h
>index 4f03bbd..825dfd4 100644
>--- a/fs/gfs2/dir.h
>+++ b/fs/gfs2/dir.h
>@@ -17,6 +17,19 @@ struct inode;
> struct gfs2_inode;
> struct gfs2_inum;
> 
>+struct gfs2_rddir_ra {
>+	u32                 rra_count;
>+	u32                 rra_req_count;
>+	u32                 rra_flags;
>+	struct gfs2_file   *rra_fp;
>+
>+	u64                *rra_blknrs;
>+};
>+
>+extern int gfs2_rddir_ra(struct file *file, unsigned flags, u64 *offset,
>+			unsigned int count);
>+extern int collect_inode_blocks(struct gfs2_rddir_ra *rra, u64 ino, unsigned int d_type);
>+
> extern struct inode *gfs2_dir_search(struct inode *dir,
> 				     const struct qstr *filename,
> 				     bool fail_on_exist);
>@@ -26,7 +39,7 @@ extern int gfs2_dir_add(struct inode *inode, const struct qstr *filename,
> 			const struct gfs2_inode *ip);
> extern int gfs2_dir_del(struct gfs2_inode *dip, const struct dentry *dentry);
> extern int gfs2_dir_read(struct inode *inode, struct dir_context *ctx,
>-			 struct file_ra_state *f_ra);
>+			 struct gfs2_rddir_ra *rra, struct file_ra_state *f_ra);
> extern int gfs2_dir_mvino(struct gfs2_inode *dip, const struct qstr *filename,
> 			  const struct gfs2_inode *nip, unsigned int new_type);
> 
>diff --git a/fs/gfs2/export.c b/fs/gfs2/export.c
>index 8b9b377..1f5085d 100644
>--- a/fs/gfs2/export.c
>+++ b/fs/gfs2/export.c
>@@ -114,7 +114,7 @@ static int gfs2_get_name(struct dentry *parent, char *name,
> 	if (error)
> 		return error;
> 
>-	error = gfs2_dir_read(dir, &gnfd.ctx, &f_ra);
>+	error = gfs2_dir_read(dir, &gnfd.ctx, NULL, &f_ra);
> 
> 	gfs2_glock_dq_uninit(&gh);
> 
>diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
>index efc078f..cccbfa9 100644
>--- a/fs/gfs2/file.c
>+++ b/fs/gfs2/file.c
>@@ -100,7 +100,7 @@ static int gfs2_readdir(struct file *file, struct dir_context *ctx)
> 	if (error)
> 		return error;
> 
>-	error = gfs2_dir_read(dir, ctx, &file->f_ra);
>+	error = gfs2_dir_read(dir, ctx, NULL, &file->f_ra);
> 
> 	gfs2_glock_dq_uninit(&d_gh);
> 
>@@ -1071,6 +1071,7 @@ const struct file_operations gfs2_file_fops = {
> 
> const struct file_operations gfs2_dir_fops = {
> 	.iterate	= gfs2_readdir,
>+	.rddir_ra       = gfs2_rddir_ra,
> 	.unlocked_ioctl	= gfs2_ioctl,
> 	.open		= gfs2_open,
> 	.release	= gfs2_release,
>@@ -1101,6 +1102,7 @@ const struct file_operations gfs2_file_fops_nolock = {
> 
> const struct file_operations gfs2_dir_fops_nolock = {
> 	.iterate	= gfs2_readdir,
>+	.rddir_ra       = gfs2_rddir_ra,
> 	.unlocked_ioctl	= gfs2_ioctl,
> 	.open		= gfs2_open,
> 	.release	= gfs2_release,
>diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
>index 0132816..4fdcbc8 100644
>--- a/fs/gfs2/incore.h
>+++ b/fs/gfs2/incore.h
>@@ -405,6 +405,7 @@ static inline struct gfs2_sbd *GFS2_SB(const struct inode *inode)
> struct gfs2_file {
> 	struct mutex f_fl_mutex;
> 	struct gfs2_holder f_fl_gh;
>+	struct gfs2_rddir_ra *f_rra;
> };
> 
> struct gfs2_revoke_replay {
>diff --git a/fs/readdir.c b/fs/readdir.c
>index 5b53d99..d5b4aa5 100644
>--- a/fs/readdir.c
>+++ b/fs/readdir.c
>@@ -302,3 +302,39 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
> 	fdput(f);
> 	return error;
> }
>+
>+SYSCALL_DEFINE4(rddir_readahead, unsigned int, fd, unsigned, flags,
>+		u64 *, offset, unsigned int, count)
>+{
>+	struct file *file;
>+	struct inode *inode;
>+	int fput_needed;
>+	int error = -ENOTDIR;
>+
>+	file = fget_light(fd, &fput_needed);
>+	if (!file)
>+		return -EBADF;
>+
>+	inode = file->f_path.dentry->d_inode;
>+
>+	if (!file->f_op || !file->f_op->rddir_ra)
>+		goto out;
>+
>+	error = security_file_permission(file, MAY_READ);
>+	if (error)
>+		goto out;
>+
>+	error = mutex_lock_killable(&inode->i_mutex);
>+	if (error)
>+		goto out;
>+
>+	error = -ENOENT;
>+	if (!IS_DEADDIR(inode)) {
>+		error = file->f_op->rddir_ra(file, flags, offset, count);
>+		file_accessed(file);
>+	}
>+	mutex_unlock(&inode->i_mutex);
>+out:
>+	fput_light(file, fput_needed);
>+	return error;
>+}
>diff --git a/include/linux/fs.h b/include/linux/fs.h
>index 121f11f..6a15e9d 100644
>--- a/include/linux/fs.h
>+++ b/include/linux/fs.h
>@@ -1526,6 +1526,7 @@ struct file_operations {
> 	ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
> 	ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
> 	int (*iterate) (struct file *, struct dir_context *);
>+	int (*rddir_ra) (struct file *, unsigned flags, u64 *offset, unsigned int count);
> 	unsigned int (*poll) (struct file *, struct poll_table_struct *);
> 	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
> 	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
>diff --git a/fs/gfs2/rddir_ra.c b/fs/gfs2/rddir_ra.c
>new file mode 100644
>index 0000000..c83af6a
>--- /dev/null
>+++ b/fs/gfs2/rddir_ra.c
>@@ -0,0 +1,188 @@
>+#include <linux/slab.h>
>+#include <linux/spinlock.h>
>+#include <linux/completion.h>
>+#include <linux/buffer_head.h>
>+#include <linux/pagemap.h>
>+#include <linux/uio.h>
>+#include <linux/blkdev.h>
>+#include <linux/mm.h>
>+#include <linux/mount.h>
>+#include <linux/sort.h>
>+#include <linux/fs.h>
>+#include <linux/gfs2_ondisk.h>
>+#include <linux/falloc.h>
>+#include <linux/swap.h>
>+#include <linux/crc32.h>
>+#include <linux/writeback.h>
>+#include <asm/uaccess.h>
>+#include <linux/dlm.h>
>+#include <linux/dlm_plock.h>
>+
>+#include "gfs2.h"
>+#include "incore.h"
>+#include "bmap.h"
>+#include "dir.h"
>+#include "glock.h"
>+#include "glops.h"
>+#include "inode.h"
>+#include "log.h"
>+#include "meta_io.h"
>+#include "quota.h"
>+#include "rgrp.h"
>+#include "trans.h"
>+#include "util.h"
>+
>+void gfs2_rddir_ra_uninit(struct gfs2_rddir_ra *rra)
>+{
>+	if (!rra || !rra->rra_blknrs)
>+		return;
>+
>+	if (is_vmalloc_addr(rra->rra_blknrs))
>+		vfree(rra->rra_blknrs);
>+	else
>+		kfree(rra->rra_blknrs);
>+	kfree(rra);
>+}
>+
>+struct gfs2_rddir_ra* gfs2_rddir_ra_init(struct gfs2_file *fp, u32 req_count)
>+{
>+	int error = -ENOMEM;
>+	u32 size = req_count * sizeof(u64);
>+	struct gfs2_rddir_ra *rra = NULL;
>+
>+	rra = kzalloc(sizeof(struct gfs2_rddir_ra), GFP_NOFS | __GFP_NOWARN);
>+	if (!rra)
>+		goto err;
>+	
>+	if (size < KMALLOC_MAX_SIZE)
>+		rra->rra_blknrs = kmalloc(size, GFP_NOFS | __GFP_NOWARN);
>+	if (!rra->rra_blknrs)
>+		rra->rra_blknrs = __vmalloc(size, GFP_NOFS, PAGE_KERNEL);
>+	if (!rra->rra_blknrs)
>+		goto free;
>+
>+	rra->rra_req_count = req_count;
>+	rra->rra_fp = fp;
>+
>+	return rra;
>+free:
>+	kfree(rra);
>+err:
>+	return ERR_PTR(error);
>+}
>+
>+static int compare_inos(const void *a, const void *b)
>+{
>+	u64 ino_a, ino_b;
>+
>+	ino_a = *(u64 *)a;
>+	ino_b = *(u64 *)b;
>+
>+	if (ino_a > ino_b)
>+		return 1;
>+	return -1;
>+}
>+
>+int gfs2_rddir_ra_inodes(struct gfs2_inode *dip, struct gfs2_rddir_ra *rra)
>+{
>+	int i, error = 0;
>+	int issue_count = 0;
>+	struct gfs2_glock *gl = dip->i_gl;
>+	struct buffer_head *bh;
>+
>+	if (!rra || !rra->rra_count || !rra->rra_blknrs)
>+		goto out;
>+
>+	sort(rra->rra_blknrs, rra->rra_count, sizeof(u64), compare_inos, NULL);
>+	for (i=0; i<rra->rra_count; i++) {
>+		bh = gfs2_getbuf(gl, rra->rra_blknrs[i], 1);
>+		if (trylock_buffer(bh)) {
>+			if (buffer_uptodate(bh)) {
>+				unlock_buffer(bh);
>+				brelse(bh);
>+				continue;
>+			}
>+			bh->b_end_io = end_buffer_read_sync;
>+			submit_bh(READA | REQ_META, bh);
>+			issue_count++;
>+			continue;
>+		}
>+		brelse(bh);
>+	}
>+	printk(KERN_WARNING "%s %s %d: Issued %d readaheads\n", __FILE__,
>+	       __FUNCTION__, __LINE__, issue_count);
>+out:
>+	return error;
>+}
>+
>+int collect_inode_blocks(struct gfs2_rddir_ra *rra, u64 ino, unsigned int d_type)
>+{
>+	if (rra->rra_count >= rra->rra_req_count)
>+		return 1; /* Collected requested blocks */
>+	
>+	rra->rra_blknrs[rra->rra_count++] = ino;
>+	
>+	return 0;
>+}
>+
>+/**
>+ * gfs2_rddir_ra - GFS2's implementation of readdir readahead
>+ * @file  : The directory to be read from
>+ * @flags : Flags to determine what blocks to readahead
>+ * @offset: Pointer to offset in dir to start prefetching from
>+ * @count : How many entries to prefetch
>+ *
>+ * Readahead inode disk blocks (and extended attribute blocks if requested)
>+ * of every directory entry
>+ *
>+ * Returns: +ve number: The number of entries for which readahead calls
>+ *                      were issued
>+ *          -ve values: For error conditions
>+ */
>+int gfs2_rddir_ra(struct file *file, unsigned flags, u64 *offset, unsigned int count)
>+{
>+	int error = 0;
>+	struct gfs2_file *fp = file->private_data;
>+	struct inode *dir = file->f_mapping->host;
>+	struct gfs2_inode *dip = GFS2_I(dir);
>+	struct gfs2_holder d_gh;
>+	struct dir_context ctx = {
>+		.actor = NULL,
>+		.pos = *offset
>+	};
>+
>+	printk(KERN_WARNING "Start gfs2_rddir_ra syscall\n");
>+
>+	error = -EINVAL;
>+	if (count <= 0)
>+		goto err;
>+	
>+	error = -EBUSY;
>+	if (fp->f_rra)
>+		goto err;
>+
>+	error = -ENOMEM;
>+	fp->f_rra = gfs2_rddir_ra_init(fp, count);
>+	if (!fp->f_rra)
>+		goto err;
>+
>+	gfs2_holder_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
>+	error = gfs2_glock_nq(&d_gh);
>+	if (error) {
>+		gfs2_holder_uninit(&d_gh);
>+		goto out;
>+	}
>+	error = gfs2_dir_read(dir, &ctx, fp->f_rra, &file->f_ra);
>+	printk(KERN_WARNING "%s %s %d: Collected %u blocks to cache - requested:%u\n",
>+	       __FILE__, __FUNCTION__, __LINE__, fp->f_rra->rra_count, fp->f_rra->rra_req_count);
>+
>+	error = gfs2_rddir_ra_inodes(dip, fp->f_rra);
>+
>+	gfs2_glock_dq_uninit(&d_gh);
>+out:
>+	gfs2_rddir_ra_uninit(fp->f_rra);
>+	fp->f_rra = NULL;
>+err:
>+	printk(KERN_WARNING "End gfs2_rddir_ra syscall\n");
>+	return error;
>+}

Actions: View | Diff

Attachments on bug 850426: 605960 | 617073 | 625592 | 678841 | 680222 | 680282 | 708389 | 731269 | 731270 | 731272 | 731273 | 731274 | 731278 | 731279 | 732739 | 732740 | 732845 | 834840 | 853502 | 909528 | 909529 | 909534 | 912745 | 917238 | 917239 | 920895 | 920896 | 920897 | 920898 | 920899 | 920902 | 920903 | 947987