search for: sparse_array_zero

When sparse_array_zero() is used for a range larger than a page, there's no need to waste time in memset() or is_zero() - we already know the page will be free()d. Signed-off-by: Eric Blake <eblake@redhat.com> --- Here's a fun one :) common/sparse/sparse.c | 7 +++++-- 1 file changed, 5 insertions(+), 2...

...turn r; + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); + return sparse_array_write (sa, buf, count, offset); } /* Zero. */ static int data_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) { - pthread_mutex_lock (&lock); + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); sparse_array_zero (sa, count, offset); - pthread_mutex_unlock (&lock); return 0; } @@ -371,9 +366,8 @@ data_zero (void *handle, uint32_t count, uint64_t offset, int may_trim) static int data_trim (void *handle, uint32_t count, uint64_t offset) { - pthread_mutex_lock (&lock); + ACQUIRE_LOCK_FOR_CUR...

On Wed, Aug 14, 2019 at 09:10:15PM -0500, Eric Blake wrote: > When sparse_array_zero() is used for a range larger than a page, > there's no need to waste time in memset() or is_zero() - we already > know the page will be free()d. > > Signed-off-by: Eric Blake <eblake@redhat.com> > --- > > Here's a fun one :) > > common/sparse/sparse.c |...

...44 --- a/common/sparse/sparse.h +++ b/common/sparse/sparse.h @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2017-2018 Red Hat Inc. + * Copyright (C) 2017-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -87,4 +87,9 @@ extern void sparse_array_zero (struct sparse_array *sa, uint32_t count, uint64_t offset) __attribute__((__nonnull__ (1))); +/* Return information about allocated pages and holes. */ +extern int sparse_array_extents (struct sparse_array *sa, + uint32_t count, u...

...44 --- a/common/sparse/sparse.h +++ b/common/sparse/sparse.h @@ -1,5 +1,5 @@ /* nbdkit - * Copyright (C) 2017-2018 Red Hat Inc. + * Copyright (C) 2017-2019 Red Hat Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -87,4 +87,9 @@ extern void sparse_array_zero (struct sparse_array *sa, uint32_t count, uint64_t offset) __attribute__((__nonnull__ (1))); +/* Return information about allocated pages and holes. */ +extern int sparse_array_extents (struct sparse_array *sa, + uint32_t count, u...

...unt, uint64_t offset, static int data_zero (void *handle, uint32_t count, uint64_t offset, uint32_t flags) { - /* Flushing, and thus FUA flag, is a no-op */ - assert ((flags & ~(NBDKIT_FLAG_FUA | NBDKIT_FLAG_MAY_TRIM)) == 0); + /* Flushing, and thus FUA flag, is a no-op. Assume that + * sparse_array_zero generally beats writes, so FAST_ZERO is a no-op. */ + assert ((flags & ~(NBDKIT_FLAG_FUA | NBDKIT_FLAG_MAY_TRIM | + NBDKIT_FLAG_FAST_ZERO)) == 0); ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); sparse_array_zero (sa, count, offset); return 0; @@ -423,6 +432,7 @@ stati...

There's more that can be done (in particular, use of CLEANUP_FREE), but this is enough to at least see if I'm on the right track. I couldn't figure out an obvious difference between common/include and common/utils, but it looks like the former is for things that are inlineable via .h only, while the latter is when you need to link in a convenience library, so this landed in the

For existing commits, this is almost identical to v1, except that I updated some commit messages and reordered the commits in a somewhat more logical sequence. The main changes are the extra commits: [06/11] plugins: Return NBD_FLAG_CAN_MULTI_CONN from some readonly plugins. - Readonly plugins that can set the flag unconditionally. [09/11] partitioning: Return NBD_FLAG_CAN_MULTI_CONN. [10/11]

Should we use attribute((nonnull)) at all? There's a very interesting history of this in libvirt -- try looking at commit eefb881 plus the commits referencing eefb881 -- but it does seem to work for me using recent GCC and Clang. I only did a few functions because annotating them gets old quickly... Rich.

...uint32_t count, uint64_t offset) + __attribute__((__nonnull__ (1, 2))); /* Zero byte range in the sparse array. * @@ -79,6 +83,8 @@ extern int sparse_array_write (struct sparse_array *sa, const void *buf, uint32_ * * This may free memory, but never returns an error. */ -extern void sparse_array_zero (struct sparse_array *sa, uint32_t count, uint64_t offset); +extern void sparse_array_zero (struct sparse_array *sa, + uint32_t count, uint64_t offset) + __attribute__((__nonnull__ (1))); #endif /* NBDKIT_SPARSE_H */ diff --git a/filters/cache/blk.h b/filters/cache...

v1 was here: https://www.redhat.com/archives/libguestfs/2019-January/msg00008.html In v2 I have provided two patches: The first patch extends attribute((nonnull)) to most internal functions, but not to the external API. The second patch uses a macro so that attribute((format)) is only used in the public API on GCC or Clang. At least in theory these headers could be used by a C compiler which

...0; + sa->max_pages = 0; sa->debug = debug; return sa; } @@ -254,6 +261,7 @@ lookup (struct sparse_array *sa, uint64_t offset, bool create, return NULL; } l2_dir[o] = page; + sa->used_pages++; } if (!page) return NULL; @@ -355,6 +363,7 @@ sparse_array_zero (struct sparse_array *sa, uint32_t count, uint64_t offset) __func__, offset); free (*l2_page); *l2_page = NULL; + sa->used_pages--; } } @@ -398,3 +407,22 @@ sparse_array_extents (struct sparse_array *sa, return 0; } + +void +spa...

This is a cover letter to a series of patches being proposed in tandem to four different projects: - nbd: Document a new NBD_CMD_FLAG_FAST_ZERO command flag - qemu: Implement the flag for both clients and server - libnbd: Implement the flag for clients - nbdkit: Implement the flag for servers, including the nbd passthrough client If you want to test the patches together, I've pushed a

Not sure what version we're up to, but this reimplements extents using the new simpler structure described in this thread: https://www.redhat.com/archives/libguestfs/2019-March/msg00077.html I also fixed most of the things that Eric pointed out in the previous review, although I need to go back over his replies and check I've got everything. This needs a bit more testing. However the

I'm not sure exactly which version we're up to, but let's say it's version 4. I'm a lot happier with this version: - all filters have been reviewed and changed where I think that's necessary - can_extents is properly defined and implemented now - NBD protocol is followed - I believe it addresses all previous review points where possible The "only" thing

I want to post this but mainly for discussion and early review. It's not safe for these patches to all go upstream yet (because not all filters have been checked/adjusted), but if any patches were to go upstream then probably 1 & 2 only are safe. File, VDDK, memory and data plugins all work, although I have only done minimal testing on them. The current tests, such as they are, all

This has already been pushed upstream. I am simply posting these here so we have a reference in the mailing list in case we find bugs later (as I'm sure we will - it's a complex patch series). Great thanks to Eric Blake for tireless review on this one. It also seems to have identified a few minor bugs in qemu along the way. Rich.

I will be following up to this email with four separate threads each addressed to the appropriate single list, with proposed changes to: - the NBD protocol - qemu: both server and client - libnbd: client - nbdkit: server The feature in question adds a new optional NBD_INFO_ packet to the NBD_OPT_GO portion of handshake, adding up to 16 bits of information that the server can advertise to the