From: Junio C Hamano <gitster@pobox.com>
To: David Turner <dturner@twopensource.com>
Cc: git@vger.kernel.org, pclouds@gmail.com
Subject: Re: [PATCH 03/19] read-cache: allow to keep mmap'd memory after reading
Date: Wed, 09 Mar 2016 15:02:01 -0800 [thread overview]
Message-ID: <xmqqziu7fe6u.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <1457548582-28302-4-git-send-email-dturner@twopensource.com> (David Turner's message of "Wed, 9 Mar 2016 13:36:06 -0500")
David Turner <dturner@twopensource.com> writes:
> From: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
As usual in Duy's patches, this one seriously lacks "why". And also
makes the reader wonder if the memory region is ever unmapped() and
if so under what condition.
> diff --git a/cache.h b/cache.h
> index 7e01403..c43ef3d 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -333,11 +333,14 @@ struct index_state {
> struct split_index *split_index;
> struct cache_time timestamp;
> unsigned name_hash_initialized : 1,
> + keep_mmap : 1,
> initialized : 1;
> struct hashmap name_hash;
> struct hashmap dir_hash;
> unsigned char sha1[20];
> struct untracked_cache *untracked;
> + void *mmap;
> + size_t mmap_size;
> };
>
> extern struct index_state the_index;
> diff --git a/read-cache.c b/read-cache.c
> index 16cc487..7e387e9 100644
> --- a/read-cache.c
> +++ b/read-cache.c
> @@ -1574,6 +1574,10 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
> mmap = xmmap(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
> if (mmap == MAP_FAILED)
> die_errno("unable to map index file");
> + if (istate->keep_mmap) {
> + istate->mmap = mmap;
> + istate->mmap_size = mmap_size;
> + }
> close(fd);
>
> hdr = mmap;
> @@ -1626,10 +1630,12 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
> src_offset += 8;
> src_offset += extsize;
> }
> - munmap(mmap, mmap_size);
> + if (!istate->keep_mmap)
> + munmap(mmap, mmap_size);
> return istate->cache_nr;
>
> unmap:
> + istate->mmap = NULL;
> munmap(mmap, mmap_size);
> die("index file corrupt");
> }
> @@ -1655,6 +1661,7 @@ int read_index_from(struct index_state *istate, const char *path)
> discard_index(split_index->base);
> else
> split_index->base = xcalloc(1, sizeof(*split_index->base));
> + split_index->base->keep_mmap = istate->keep_mmap;
> ret = do_read_index(split_index->base,
> git_path("sharedindex.%s",
> sha1_to_hex(split_index->base_sha1)), 1);
> @@ -1698,6 +1705,10 @@ int discard_index(struct index_state *istate)
> free(istate->cache);
> istate->cache = NULL;
> istate->cache_alloc = 0;
> + if (istate->keep_mmap && istate->mmap) {
> + munmap(istate->mmap, istate->mmap_size);
> + istate->mmap = NULL;
> + }
> discard_split_index(istate);
> free_untracked_cache(istate->untracked);
> istate->untracked = NULL;
next prev parent reply other threads:[~2016-03-09 23:02 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 18:36 [PATCH 00/19] index-helper, watchman David Turner
2016-03-09 18:36 ` [PATCH 01/19] trace.c: add GIT_TRACE_PACK_STATS for pack usage statistics David Turner
2016-03-09 22:58 ` Junio C Hamano
2016-03-10 0:05 ` David Turner
2016-03-10 10:59 ` Duy Nguyen
2016-03-09 18:36 ` [PATCH 02/19] read-cache.c: fix constness of verify_hdr() David Turner
2016-03-09 18:36 ` [PATCH 03/19] read-cache: allow to keep mmap'd memory after reading David Turner
2016-03-09 23:02 ` Junio C Hamano [this message]
2016-03-10 0:09 ` David Turner
2016-03-09 18:36 ` [PATCH 04/19] index-helper: new daemon for caching index and related stuff David Turner
2016-03-09 23:09 ` Junio C Hamano
2016-03-09 23:21 ` Junio C Hamano
2016-03-10 0:01 ` David Turner
2016-03-10 11:17 ` Duy Nguyen
2016-03-10 20:22 ` David Turner
2016-03-11 1:11 ` Duy Nguyen
2016-03-10 0:18 ` David Turner
2016-03-15 11:56 ` Duy Nguyen
2016-03-15 15:56 ` Junio C Hamano
2016-03-15 11:52 ` Duy Nguyen
2016-03-09 18:36 ` [PATCH 05/19] trace.c: add GIT_TRACE_INDEX_STATS for index statistics David Turner
2016-03-09 18:36 ` [PATCH 06/19] index-helper: add --strict David Turner
2016-03-09 18:36 ` [PATCH 07/19] daemonize(): set a flag before exiting the main process David Turner
2016-03-09 18:36 ` [PATCH 08/19] index-helper: add --detach David Turner
2016-03-09 18:36 ` [PATCH 09/19] index-helper: add Windows support David Turner
2016-03-16 11:42 ` Duy Nguyen
2016-03-17 12:18 ` Johannes Schindelin
2016-03-17 12:59 ` Duy Nguyen
2016-03-09 18:36 ` [PATCH 10/19] read-cache: add watchman 'WAMA' extension David Turner
2016-03-09 18:36 ` [PATCH 11/19] Add watchman support to reduce index refresh cost David Turner
2016-03-09 18:36 ` [PATCH 12/19] read-cache: allow index-helper to prepare shm before git reads it David Turner
2016-03-09 18:36 ` [PATCH 13/19] index-helper: use watchman to avoid refreshing index with lstat() David Turner
2016-03-09 18:36 ` [PATCH 14/19] update-index: enable/disable watchman support David Turner
2016-03-09 18:36 ` [PATCH 15/19] unpack-trees: preserve index extensions David Turner
2016-03-09 18:36 ` [PATCH 16/19] index-helper: rewrite pidfile after daemonizing David Turner
2016-03-09 18:36 ` [PATCH 17/19] index-helper: process management David Turner
2016-03-09 18:36 ` [PATCH 18/19] index-helper: autorun David Turner
2016-03-15 12:12 ` Duy Nguyen
2016-03-15 14:26 ` Johannes Schindelin
2016-03-16 11:37 ` Duy Nguyen
2016-03-16 18:11 ` David Turner
2016-03-16 18:27 ` Johannes Schindelin
2016-03-17 13:02 ` Duy Nguyen
2016-03-17 14:43 ` Johannes Schindelin
2016-03-17 18:31 ` David Turner
2016-03-18 0:50 ` Duy Nguyen
2016-03-18 7:14 ` Johannes Schindelin
2016-03-18 7:44 ` Duy Nguyen
2016-03-18 17:22 ` David Turner
2016-03-18 23:09 ` Duy Nguyen
2016-03-18 7:17 ` Johannes Schindelin
2016-03-18 7:34 ` Duy Nguyen
2016-03-18 15:57 ` Johannes Schindelin
2016-03-09 18:36 ` [PATCH 19/19] hack: watchman/untracked cache mashup David Turner
2016-03-15 12:31 ` Duy Nguyen
2016-03-17 0:56 ` David Turner
2016-03-17 13:06 ` Duy Nguyen
2016-03-17 18:08 ` David Turner
2016-03-29 17:09 ` [PATCH 00/19] index-helper, watchman Torsten Bögershausen
2016-03-29 21:51 ` David Turner
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