Eric Lee / smarc-fsl-linux-kernel

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Commit 5565a9d884327ac45d49041f1b846dac273e110c

Authored by Maxim Patlasov
Committed by Miklos Szeredi
1 parent 7c190c8b9c

fuse: optimize __fuse_direct_io() 

__fuse_direct_io() allocates fuse-requests by calling fuse_get_req(fc, n). The
patch calculates 'n' based on iov[] array. This is useful because allocating
FUSE_MAX_PAGES_PER_REQ page pointers and descriptors for each fuse request
would be waste of memory in case of iov-s of smaller size.

Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

Showing 1 changed file with 21 additions and 4 deletions Side-by-side Diff

... ... @@ -1088,14 +1088,14 @@
1088 1088 return 0;
1089 1089 }
1090 1090  
1091   - while (nbytes < *nbytesp && req->num_pages < FUSE_MAX_PAGES_PER_REQ) {
  1091 + while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1092 1092 unsigned npages;
1093 1093 unsigned long user_addr = fuse_get_user_addr(ii);
1094 1094 unsigned offset = user_addr & ~PAGE_MASK;
1095 1095 size_t frag_size = fuse_get_frag_size(ii, *nbytesp - nbytes);
1096 1096 int ret;
1097 1097  
1098   - unsigned n = FUSE_MAX_PAGES_PER_REQ - req->num_pages;
  1098 + unsigned n = req->max_pages - req->num_pages;
1099 1099 frag_size = min_t(size_t, frag_size, n << PAGE_SHIFT);
1100 1100  
1101 1101 npages = (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
... ... @@ -1131,6 +1131,23 @@
1131 1131 return 0;
1132 1132 }
1133 1133  
  1134 +static inline int fuse_iter_npages(const struct iov_iter *ii_p)
  1135 +{
  1136 + struct iov_iter ii = *ii_p;
  1137 + int npages = 0;
  1138 +
  1139 + while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
  1140 + unsigned long user_addr = fuse_get_user_addr(&ii);
  1141 + unsigned offset = user_addr & ~PAGE_MASK;
  1142 + size_t frag_size = iov_iter_single_seg_count(&ii);
  1143 +
  1144 + npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
  1145 + iov_iter_advance(&ii, frag_size);
  1146 + }
  1147 +
  1148 + return min(npages, FUSE_MAX_PAGES_PER_REQ);
  1149 +}
  1150 +
1134 1151 static ssize_t __fuse_direct_io(struct file *file, const struct iovec *iov,
1135 1152 unsigned long nr_segs, size_t count,
1136 1153 loff_t *ppos, int write)
... ... @@ -1145,7 +1162,7 @@
1145 1162  
1146 1163 iov_iter_init(&ii, iov, nr_segs, count, 0);
1147 1164  
1148   - req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
  1165 + req = fuse_get_req(fc, fuse_iter_npages(&ii));
1149 1166 if (IS_ERR(req))
1150 1167 return PTR_ERR(req);
1151 1168  
... ... @@ -1180,7 +1197,7 @@
1180 1197 break;
1181 1198 if (count) {
1182 1199 fuse_put_request(fc, req);
1183   - req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
  1200 + req = fuse_get_req(fc, fuse_iter_npages(&ii));
1184 1201 if (IS_ERR(req))
1185 1202 break;
1186 1203 }