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author | Miklos Szeredi <mszeredi@redhat.com> | 2018-10-01 10:07:06 +0200 |
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committer | Miklos Szeredi <mszeredi@redhat.com> | 2018-10-01 10:07:06 +0200 |
commit | e52a8250480acd3b26534793c61816e30d85fbb6 (patch) | |
tree | be2ae4d947e7fb876eae27926f70cf9c702243b2 /fs/fuse/dev.c | |
parent | 5da784cce4308ae10a79e3c8c41b13fb9568e4e0 (diff) | |
download | linux-e52a8250480acd3b26534793c61816e30d85fbb6.tar.bz2 |
fuse: realloc page array
Writeback caching currently allocates requests with the maximum number of
possible pages, while the actual number of pages per request depends on a
couple of factors that cannot be determined when the request is allocated
(whether page is already under writeback, whether page is contiguous with
previous pages already added to a request).
This patch allows such requests to start with no page allocation (all pages
inline) and grow the page array on demand.
If the max_pages tunable remains the default value, then this will mean
just one allocation that is the same size as before. If the tunable is
larger, then this adds at most 3 additional memory allocations (which is
generously compensated by the improved performance from the larger
request).
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/fuse/dev.c')
-rw-r--r-- | fs/fuse/dev.c | 49 |
1 files changed, 45 insertions, 4 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 69d4df78a417..ae813e609932 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -54,6 +54,18 @@ static void fuse_request_init(struct fuse_req *req, struct page **pages, __set_bit(FR_PENDING, &req->flags); } +static struct page **fuse_req_pages_alloc(unsigned int npages, gfp_t flags, + struct fuse_page_desc **desc) +{ + struct page **pages; + + pages = kzalloc(npages * (sizeof(struct page *) + + sizeof(struct fuse_page_desc)), flags); + *desc = (void *) pages + npages * sizeof(struct page *); + + return pages; +} + static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags) { struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags); @@ -63,13 +75,12 @@ static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags) WARN_ON(npages > FUSE_MAX_MAX_PAGES); if (npages > FUSE_REQ_INLINE_PAGES) { - pages = kzalloc(npages * (sizeof(*pages) + - sizeof(*page_descs)), flags); + pages = fuse_req_pages_alloc(npages, flags, + &page_descs); if (!pages) { kmem_cache_free(fuse_req_cachep, req); return NULL; } - page_descs = (void *) pages + npages * sizeof(*pages); } else if (npages) { pages = req->inline_pages; page_descs = req->inline_page_descs; @@ -91,11 +102,41 @@ struct fuse_req *fuse_request_alloc_nofs(unsigned npages) return __fuse_request_alloc(npages, GFP_NOFS); } -void fuse_request_free(struct fuse_req *req) +static void fuse_req_pages_free(struct fuse_req *req) { if (req->pages != req->inline_pages) kfree(req->pages); +} + +bool fuse_req_realloc_pages(struct fuse_conn *fc, struct fuse_req *req, + gfp_t flags) +{ + struct page **pages; + struct fuse_page_desc *page_descs; + unsigned int npages = min_t(unsigned int, + max_t(unsigned int, req->max_pages * 2, + FUSE_DEFAULT_MAX_PAGES_PER_REQ), + fc->max_pages); + WARN_ON(npages <= req->max_pages); + pages = fuse_req_pages_alloc(npages, flags, &page_descs); + if (!pages) + return false; + + memcpy(pages, req->pages, sizeof(struct page *) * req->max_pages); + memcpy(page_descs, req->page_descs, + sizeof(struct fuse_page_desc) * req->max_pages); + fuse_req_pages_free(req); + req->pages = pages; + req->page_descs = page_descs; + req->max_pages = npages; + + return true; +} + +void fuse_request_free(struct fuse_req *req) +{ + fuse_req_pages_free(req); kmem_cache_free(fuse_req_cachep, req); } |